Wilsons Sandbox

Posted: **Sun Sep 28, 2008 12:19 pm**

I installed the last gear in the balancer system. It provide a bit more tension. Still the clearance by the bottom of the case looks tight. These new sprockets enable me to use the longer doo spring but most likely I'll consider the torsion. Now, if I apply a lot of tension to the adjuster lever, I can take a lot of slack out. However this puts a lot of pressure on the rubber dampening material almost to the point the chain is forced into it. I'm left hypothesizing that too much spring pressure/tension is not a good thing. Rather, just enough tension and more frequent adjustments is best. Again, people will note the spring doesn't matter once the adjuster (doo) is locked down via tightening the adjuster bolt. However, the initial spring pressure and its resultant tension on the dampening material does matter. In fact, further I'd suggest too much spring pressure WILL hasten these sprockets service life--not the metal sprocket itself but the dampening material surrounding the sprockets which directly determines balancer chain slack. Not to mention as this material wears, bits and peices drop off and can clog (seriously) the oil screen. Now, my OEM doo exploded early and was replace with the Eagle Mikes robusto. But there's no telling exactly what damage to the balancer sprockets was done. I will say at the time of dooing (3k smiles), I had plenty of black plastic crap in my oil screen and I installed the smallest of the two springs. I can't remember if the bigger spring would fit but my thought was get the smaller one on if I could. My thinking then was "the more tension the better." But now I no longer feel this way after especially after spending $200 replacing all these sprockets. What this all boils down to is analyzing cost benefit in answering: What's the best spring to install for reasonable tension that provides the longest service (i.e., don't have to crack the case to make a spring change)? At this point, I'd like to measure force on the lever from all springs. Clearly these will decrease toward the springs natural, static state. But the goal would be to provide the least amount of pressure across a big range and ideally the entire usable range of motion of the adjuster. In my situation prior to replacing the gear, the smallest spring lost tension just when my chain started coming into contact with the bottom of the case...a good thing! However the longer spring would have been way too slack long ago. My concern with the torsion spring is it would have allowed the adjuster to continue rotating the shaft and removing slack (to the point the bolt hits the right side of the adjuster = max) which doesn't provide any benefit of course. However it seems the torsion is the least likely to disconnect from it's position/location. I will note my small Eagle Mike spring stayed connected the entire time even when it reached its natural, unstretched state. So what to doo? I'm going to measure the springs installed tensions with my 'like new' system. If the torsion isn't too much higher than the large spring, makes sense to really consider it. However if the tension is too high, perhaps the big spring little spring might prove a better combo even though this requires 'going in.' Of course the primary concern is having SOME chain tension all the time which with the larger spring, well, you never know unless you have the 'window with a view mod.' I'm not inclined to doo that just yet. Anyway, after some measurements it could come down to how important over- tension is vs. a point of no tension. Of course, the floor is open to debate... Brian

Posted: **Sun Sep 28, 2008 4:25 pm**

Hi Brian, I been following your doo saga since you started.I believe when I installed Eagle Mike's doo and torsion spring (when it first came out I believe) as far as I remember the locking bolt was somewhere right around the centre of the adjustment slot. The reason I remember the bolt position is while I was doing the install I was referencing a Clymer manual and Marknet's article and both showed the tensioned doo in pretty much this position. I looked the chain and sprockets over pretty closely and the dampening material was all intact on my sprockets (around 10,000 kms). I would think that with new sprockets, no real wear on the crankshaft sprocket and a chain that if I remember reading properly was well within spec your doo should be in somewhere around the same position. I cleaned the oil strainer at the same time and found the missing doo spring end and a little silicon but no dampener material so I think it's safe to say the material on the sprockets that I can't see is still there. This leads my to what puzzles me a bit, if I remember properly you said your doo was close to the end of it's adjustment slot. Is it possible that you have some slop in one or more of the bearings, their shafts or the bearing bores in the cases. I say this because a small amount of wear any of the above might account for the advance position of your doo even with all of the new sprockets. No doubt you have checked all of this but just a thought...have a great evening.....Greg

--- On Sun, 9/28/08, boulder_adv_rider wrote: From: boulder_adv_rider Subject: [DSN_KLR650] Re: What to doo next? replaced all 3 gears...no more slack'in To: DSN_KLR650@yahoogroups.com Received: Sunday, September 28, 2008, 2:19 PM I installed the last gear in the balancer system. It provide a bit more tension. Still the clearance by the bottom of the case looks tight. These new sprockets enable me to use the longer doo spring but most likely I'll consider the torsion. Now, if I apply a lot of tension to the adjuster lever, I can take a lot of slack out. However this puts a lot of pressure on the rubber dampening material almost to the point the chain is forced into it. I'm left hypothesizing that too much spring pressure/tension is not a good thing. Rather, just enough tension and more frequent adjustments is best. Again, people will note the spring doesn't matter once the adjuster (doo) is locked down via tightening the adjuster bolt. However, the initial spring pressure and its resultant tension on the dampening material does matter. In fact, further I'd suggest too much spring pressure WILL hasten these sprockets service life--not the metal sprocket itself but the dampening material surrounding the sprockets which directly determines balancer chain slack. Not to mention as this material wears, bits and peices drop off and can clog (seriously) the oil screen. Now, my OEM doo exploded early and was replace with the Eagle Mikes robusto. But there's no telling exactly what damage to the balancer sprockets was done. I will say at the time of dooing (3k smiles), I had plenty of black plastic crap in my oil screen and I installed the smallest of the two springs. I can't remember if the bigger spring would fit but my thought was get the smaller one on if I could. My thinking then was "the more tension the better." But now I no longer feel this way after especially after spending $200 replacing all these sprockets. What this all boils down to is analyzing cost benefit in answering: What's the best spring to install for reasonable tension that provides the longest service (i.e., don't have to crack the case to make a spring change)? At this point, I'd like to measure force on the lever from all springs. Clearly these will decrease toward the springs natural, static state. But the goal would be to provide the least amount of pressure across a big range and ideally the entire usable range of motion of the adjuster. In my situation prior to replacing the gear, the smallest spring lost tension just when my chain started coming into contact with the bottom of the case...a good thing! However the longer spring would have been way too slack long ago. My concern with the torsion spring is it would have allowed the adjuster to continue rotating the shaft and removing slack (to the point the bolt hits the right side of the adjuster = max) which doesn't provide any benefit of course. However it seems the torsion is the least likely to disconnect from it's position/location. I will note my small Eagle Mike spring stayed connected the entire time even when it reached its natural, unstretched state. So what to doo? I'm going to measure the springs installed tensions with my 'like new' system. If the torsion isn't too much higher than the large spring, makes sense to really consider it. However if the tension is too high, perhaps the big spring little spring might prove a better combo even though this requires 'going in.' Of course the primary concern is having SOME chain tension all the time which with the larger spring, well, you never know unless you have the 'window with a view mod.' I'm not inclined to doo that just yet. Anyway, after some measurements it could come down to how important over- tension is vs. a point of no tension. Of course, the floor is open to debate... Brian __________________________________________________________________ Yahoo! Canada Toolbar: Search from anywhere on the web, and bookmark your favourite sites. Download it now at http://ca.toolbar.yahoo.com [Non-text portions of this message have been removed]

Posted: **Sun Sep 28, 2008 5:53 pm**

--- In DSN_KLR650@yahoogroups.com, "boulder_adv_rider" wrote:

> > I installed the last gear in the balancer system. It provide a bit > more tension. Still the clearance by the bottom of the case looks > tight. These new sprockets enable me to use the longer doo spring > but most likely I'll consider the torsion. > > Now, if I apply a lot of tension to the adjuster lever, I can take a > lot of slack out. However this puts a lot of pressure on the rubber > dampening material almost to the point the chain is forced into it. > I'm left hypothesizing that too much spring pressure/tension is not a > good thing. Rather, just enough tension and more frequent > adjustments is best. > > Again, people will note the spring doesn't matter once the adjuster > (doo) is locked down via tightening the adjuster bolt. However, the > initial spring pressure and its resultant tension on the dampening > material does matter. In fact, further I'd suggest too much spring > pressure WILL hasten these sprockets service life--not the metal > sprocket itself but the dampening material surrounding the sprockets > which directly determines balancer chain slack. Not to mention as > this material wears, bits and peices drop off and can clog > (seriously) the oil screen. > > Now, my OEM doo exploded early and was replace with the Eagle Mikes > robusto. But there's no telling exactly what damage to the balancer > sprockets was done. I will say at the time of dooing (3k smiles), I > had plenty of black plastic crap in my oil screen and I installed the > smallest of the two springs. I can't remember if the bigger spring > would fit but my thought was get the smaller one on if I could. My > thinking then was "the more tension the better." But now I no longer > feel this way after especially after spending $200 replacing all > these sprockets. > > What this all boils down to is analyzing cost benefit in answering: > What's the best spring to install for reasonable tension that > provides the longest service (i.e., don't have to crack the case to > make a spring change)? At this point, I'd like to measure force on > the lever from all springs. Clearly these will decrease toward the > springs natural, static state. But the goal would be to provide the > least amount of pressure across a big range and ideally the entire > usable range of motion of the adjuster. In my situation prior to > replacing the gear, the smallest spring lost tension just when my > chain started coming into contact with the bottom of the case...a > good thing! However the longer spring would have been way too slack > long ago. My concern with the torsion spring is it would have > allowed the adjuster to continue rotating the shaft and removing > slack (to the point the bolt hits the right side of the adjuster = > max) which doesn't provide any benefit of course. However it seems > the torsion is the least likely to disconnect from it's > position/location. I will note my small Eagle Mike spring stayed > connected the entire time even when it reached its natural, > unstretched state. > > So what to doo? I'm going to measure the springs installed tensions > with my 'like new' system. If the torsion isn't too much higher than > the large spring, makes sense to really consider it. However if the > tension is too high, perhaps the big spring little spring might prove > a better combo even though this requires 'going in.' Of course the > primary concern is having SOME chain tension all the time which with > the larger spring, well, you never know unless you have the 'window > with a view mod.' I'm not inclined to doo that just yet. Anyway, > after some measurements it could come down to how important over- > tension is vs. a point of no tension. Of course, the floor is open > to debate... > > Brian

The baseline idler shaft torque (BIST) for the aftermarket comes from a new KLR with zero miles. The BIST is dependent on the stretch of the idler shaft spring. To my knowledge, Kawasaki has never published any technical information regarding the allowable range of idler shaft torque, which has varied over the KLR model years due to the use of different idler shaft spring part numbers and specifications. The torsion spring appears to be a better way to apply idler shaft torque, and, ideally, hopefully it meets Kawasaki's idler shaft torque design specifications. I think the people with the best info. are Pete Chester, Eagle Mike, Bill Watson and others(?). ED,,,,,wing'n it

Posted: **Sun Sep 28, 2008 5:56 pm**

--- In DSN_KLR650@yahoogroups.com, Greg May wrote:

> > Hi Brian, I been following your doo saga since you started.I

believe when I installed Eagle Mike's doo and torsion spring (when it first came out I believe) as far as I remember the locking bolt was somewhere right around the centre of the adjustment slot. The reason I remember the bolt position is while I was doing the install I was referencing a Clymer manual and Marknet's article and both showed the tensioned doo in pretty much this position. I looked the chain and sprockets over pretty closely and the dampening material was all intact on my sprockets (around 10,000 kms). I would think that with new sprockets, no real wear on the crankshaft sprocket and a chain that if I remember reading properly was well within spec your doo should be in somewhere around the same position. I cleaned the oil strainer at the same time and found the missing doo spring end and a little silicon but no dampener material so I think it's safe to say the material on

> the sprockets that I can't see is still there. > > This leads my to what puzzles me a bit, if I remember properly you

said your doo was close to the end of it's adjustment slot. Is it possible that you have some slop in one or more of the bearings, their shafts or the bearing bores in the cases. I say this because a small amount of wear any of the above might account for the advance position of your doo even with all of the new sprockets. No doubt you have checked all of this but just a thought...have a great evening.....Greg Also the chain guides, etc. ED

Posted: **Sun Sep 28, 2008 9:23 pm**

Hey Greg - It's difficult to measure the crank & bearing wear and counter balancer bearing and shaft wear without serious effort. If I suspected the counter balancer bearings ($10 each) and/or shaft ($72) I'd replace them. However, my quick insitu check/inspection doesn't indicate any play. I placed a spud bar in the shaft and tried moving it. I don't feel any play. Minding the threads inside the crankshaft, I did the same--no play. But your observation of the adjuster's position did help. With the larger spring installed and new gears the bolt falls in the middle of the adjuster's RoM. Below is info I'm not sure many are interested in, but I documented my observations so I'll post them. I measured the force of the large spring at 5.25 lbs installed. This spring measures 1.484" in natural state and stretched to roughly 1.567" installed. Comparatively the small spring measures 1.355" in natural state and stretched to same rough 1.567" but pulls 7.25 lbs of pressure installed. So the larger spring is .129" longer but pulls 38% less. However it looks like the longer spring doesn't have much pull range. Without applying any force, the distance from the hole in the adjuster lever (where right side of spring is inserted) to the left side of the case post (where the other side of the spring (left) slides over) is 1.973". But when installed, both springs contract this distance to the 1.567". Theoretically, this leaves .083" (1.567" - 1.484") of pull for the larger spring and .212" for the smaller spring. However it was difficult to measure accurately the stretched-into-position spring length (1.567"). So I measured another way for comparison; I hooked the right side of the large spring (zero tension) and measured the distance from the left side of the spring to the left side of the case's post which is .208". So the large spring has .208" of contraction before it's slack--not very much. Of course the spring gets connected on the right side to a lever which is connected to an eccentric shaft which means as the spring tensions, the adjuster (doo) moves slightly more than each unit of spring contraction.

Posted: **Sun Sep 28, 2008 9:23 pm**

Hey Greg - It's difficult to measure the crank & bearing wear and counter balancer bearing and shaft wear without serious effort. If I suspected the counter balancer bearings ($10 each) and/or shaft ($72) I'd replace them. However, my quick insitu check/inspection doesn't indicate any play. I placed a spud bar in the shaft and tried moving it. I don't feel any play. Minding the threads inside the crankshaft, I did the same--no play. But your observation of the adjuster's position did help. With the larger spring installed and new gears the bolt falls in the middle of the adjuster's RoM. Below is info I'm not sure many are interested in, but I documented my observations so I'll post them. I measured the force of the large spring at 5.25 lbs installed. This spring measures 1.484" in natural state and stretched to roughly 1.567" installed. Comparatively the small spring measures 1.355" in natural state and stretched to same rough 1.567" but pulls 7.25 lbs of pressure installed. So the larger spring is .129" longer but pulls 38% less. However it looks like the longer spring doesn't have much pull range. Without applying any force, the distance from the hole in the adjuster lever (where right side of spring is inserted) to the left side of the case post (where the other side of the spring (left) slides over) is 1.973". But when installed, both springs contract this distance to the 1.567". Theoretically, this leaves .083" (1.567" - 1.484") of pull for the larger spring and .212" for the smaller spring. However it was difficult to measure accurately the stretched-into-position spring length (1.567"). So I measured another way for comparison; I hooked the right side of the large spring (zero tension) and measured the distance from the left side of the spring to the left side of the case's post which is .208". So the large spring has .208" of contraction before it's slack--not very much. Of course the spring gets connected on the right side to a lever which is connected to an eccentric shaft which means as the spring tensions, the adjuster (doo) moves slightly more than each unit of spring contraction.

Posted: **Sun Sep 28, 2008 10:01 pm**

Ed - I don't think the chain guides do anything to adjust slack. These appear to me to be guides that prevent a slacked chain from jumping off the system. In fact, I couldn't remove the chain without removing the idler shaft and these guides (ultimately the upper balancer sprocket, too). Now, I haven't replaced these guides and unfortunately have no idea what virgin ones look like. Brian

Posted: **Sun Sep 28, 2008 10:52 pm**

--- In DSN_KLR650@yahoogroups.com, "boulder_adv_rider" wrote:

> > I installed the last gear in the balancer system. It provide a bit > more tension. Still the clearance by the bottom of the case looks > tight. These new sprockets enable me to use the longer doo spring > but most likely I'll consider the torsion. > > Now, if I apply a lot of tension to the adjuster lever, I can take a > lot of slack out. However this puts a lot of pressure on the rubber > dampening material almost to the point the chain is forced into it. > I'm left hypothesizing that too much spring pressure/tension is not a > good thing. Rather, just enough tension and more frequent > adjustments is best. > > Again, people will note the spring doesn't matter once the adjuster > (doo) is locked down via tightening the adjuster bolt. However, the > initial spring pressure and its resultant tension on the dampening > material does matter. In fact, further I'd suggest too much spring > pressure WILL hasten these sprockets service life--not the metal > sprocket itself but the dampening material surrounding the sprockets > which directly determines balancer chain slack. Not to mention as > this material wears, bits and peices drop off and can clog > (seriously) the oil screen. > > Now, my OEM doo exploded early and was replace with the Eagle Mikes > robusto. But there's no telling exactly what damage to the balancer > sprockets was done. I will say at the time of dooing (3k smiles), I > had plenty of black plastic crap in my oil screen and I installed the > smallest of the two springs. I can't remember if the bigger spring > would fit but my thought was get the smaller one on if I could. My > thinking then was "the more tension the better." But now I no longer > feel this way after especially after spending $200 replacing all > these sprockets. > > What this all boils down to is analyzing cost benefit in answering: > What's the best spring to install for reasonable tension that > provides the longest service (i.e., don't have to crack the case to > make a spring change)? At this point, I'd like to measure force on > the lever from all springs. Clearly these will decrease toward the > springs natural, static state. But the goal would be to provide the > least amount of pressure across a big range and ideally the entire > usable range of motion of the adjuster. In my situation prior to > replacing the gear, the smallest spring lost tension just when my > chain started coming into contact with the bottom of the case...a > good thing! However the longer spring would have been way too slack > long ago. My concern with the torsion spring is it would have > allowed the adjuster to continue rotating the shaft and removing > slack (to the point the bolt hits the right side of the adjuster = > max) which doesn't provide any benefit of course. However it seems > the torsion is the least likely to disconnect from it's > position/location. I will note my small Eagle Mike spring stayed > connected the entire time even when it reached its natural, > unstretched state. > > So what to doo? I'm going to measure the springs installed tensions > with my 'like new' system. If the torsion isn't too much higher than > the large spring, makes sense to really consider it. However if the > tension is too high, perhaps the big spring little spring might prove > a better combo even though this requires 'going in.' Of course the > primary concern is having SOME chain tension all the time which with > the larger spring, well, you never know unless you have the 'window > with a view mod.' I'm not inclined to doo that just yet. Anyway, > after some measurements it could come down to how important over- > tension is vs. a point of no tension. Of course, the floor is open > to debate... > > Brian

Brian, Several considerations: Sprocket and chain wear - a properly tensioned system shows less wear in my experience. Do the current spring setups cause excess wear to the system, possible due to excess tension? Again - this hasn't shown up. Only a loose system seems to allow the chain to contact the case. Detail and experience below. I measured the spring stretch on a few fairly new (3 miles to 500 miles, pre 2008) motorcycles, with the factory spring still in place. Knowing the wire diameter, number of coils, etc, one can come up with a close guess at the initial tension. One doesn't know how much wear the Kawasaki engineers expected immediately - this would affect tension early in the bikes life. I'm personally not sure they thought about it much. I've purchased all the various spring sizes, back to the 600. The spring wire got larger with every change. I can tell you all the spring install recommendations I make are based on what I've learned, and none will cause engine damage. From a practical point, if they did, I'd know about it by now. I've know been into more than 300 engines at tech days or one-on-one in my shop. Based on this experience, I'd say a properly tensioned (or de-slacked) balancer system shows less wear , as evidenced by less travel of the balancer lever/doo. I purchased a couple of very used engines a couple of years ago, one of which had been to a tech day about 30K miles before. This engine had my lever and the longer spring in it. It still had some tension of the spring. The lever did not move when the bolt was loosened, or move appreciably when tapped with a screwdriver handle on the right side (in case it was stuck to the inner engine case). The lever just doesn't show much movement, indicating wear in the balancer system, when everything is properly set up. I've measured several balancer chains. All of them were within the wear limits no matter how many miles. I know some people have advocated replacing the chain and sprockets as a matter of routine at about 30K miles. I've always disagreed with that, as the sprockets seems to be the parts showing wear. I really don't think the sprocket wear (the rubber) is a big cause for concern. I've seen evidence of the chain hitting the cases in a couple of places. In every case in my experience, the chain was not properly tensioned at the time - it was loose. In the past, I've removed some of the aluminum where the chain runs close to the idler sprocket. This doesn't hurt anything structurally. Even when everything is masked off, a fair bit of aluminum can end up in the oil, so a couple of flushes would be a good thing. The amount of wear created by the chain rubbing at this lower point with a properly tensioned system has often been discussed, but no hard data exists that I'm aware of. At several tech days I did slide a feeler gauge in between the chain (after the upgraded lever and spring was installed) and there was .020 to .030 clearance. I think that's the most data that was ever gathered, at least that I know of. I know of some people that experimented with other spring setups, as when Jake flipped the spring lever 180 and re-routed the spring. With the amount of stretch there, a bunch more tension was put into the system. I never heard of a problem there with the tension - I know of one spring breaking at some point. I never bothered to calculate the tension involved when one did that. I knew it was more than I'd want to use - but I never heard of it damaging the engine. The torsion spring is captured on install, and has a longer adjustment arc. There's a couple of tricks that I'll be incorporating into the install instructions in the next few days. With the extension spring setup there will always be a little extra slack in the system, depending on how much play there is between the balancer lever and the idler shaft. This is because the extension spring pulls on the linkage, rather than directly on the adjustment lever. all the best, Mike

Posted: **Mon Sep 29, 2008 2:05 am**

Ed Dobson wrote: I think the people with the best info. are Pete Chester, Eagle Mike, Bill Watson and others(?). Thanks for that vote of confidence, Ed. Brian, from what I've learned so far from Eagle Mike, it appears that an always-snug idler system, even a really-tight system, has less idler sprocket wear than a loose system that gets impact loading from the chain rattling around on the sprockets. I have one piece of data to add to this. I've got 38K miles on my '04, and have always run a lot of tension. At 1200 miles from brand-new I put in the Eagle Mike doo and used the short 35 mm extension spring because I didn't want to tear into it for a long while. At 7K miles I put in a pre-production torsion spring preloaded pretty high (over 90 degrees, again for the same reason). I just did the oil screen cleanout last week, and there was very little material from the idler sprockets that has come off in my opinion. I've posted a picture on the last page of photos, under "watt-man". There were three types of debris. Silicone sealant, machining debris (seemed like aluminum chips from end-milling the cases) and small pieces of idler sprocket rubber. I strain the oil at each change and haven't seen any other pieces other than these. Hope this helps. Bill [Non-text portions of this message have been removed]

Posted: **Mon Sep 29, 2008 1:37 pm**

Mike - Thanks for the considerations and commentary. I think we all agree a properly tensioned system is best. Yet few seem to have seen the damage I've experienced with one extreme in riding (harsh). Here I am at 20k miles with a complete set of worn-out balancer gears yet I take great care of my KLR once I'm off the seat. So ignoring slack for a moment, I can't help but draw the typical parallel to an overly tight drive chain which results in excessive and premature sprocket/chain wear. Again, I'm not saying it's the case here, rather I'm reaching out to experts to gather more information and share what I'm observing. Most everyone will tell you the KLR clutch is great (never a problem), but then listen to Revmattin describe what happens to a standard clutch under 'gumbo' assault. I can testify I've melted brand new clutches in bouts of extended time in deep (sugar bowl) sand. Harsh conditions bring on these aberrations and compound less than ideal situations/setups (in this case lack of oil cooling capacity). Part of the problem in my KLR's history/analysis is I replaced my doo at 3k miles. My OEM doo was destroyed with the spring left dangling like a Kawi dealer's business card. So how much wear existed at this time and how much damage was due to slack + harsh riding? Don't know. Clearly, notable amounts of black material in the screen at the time suggests there was damage, but I didn't take notes. Now I look at these gears with missing chunks and deep (chain) divots in the dampening rubber and wonder. No doubt a slack chain going taught would do this. The grind marks in the case are limited to two areas and (like you found) were caused by too much slack at some point. I don't think the engineers at Kaw made a spring calculation either. Clearly, failed springs discovered via its warranty program most likely 'forced' a calculation: make it stronger...and stronger. Your analysis confirms this. Of course, it's been the adjuster (doo) that's been the devil. Your work fixed this. I agree don't replace the balancer chain unless it's beyond the service limit. But you said, "I really don't think the sprocket wear (the rubber) is a big cause for concern." I completely disagree especially if you rode hard knowing/unknowingly with slack in the system. The rubber is the major consumable in the system evidenced by it showing up in the oil screen and the following. Before repairs, here at 20k miles there is zero slack mitigation capacity because the rubber is shot. The chain is rubbing the bottom of the case full-time and any rotation of the idler shaft clockwise forces the chain deeper into the case. After replacing these sprockets, there is slack mitigation confirmed by the adjuster bolt being in the middle of the adjuster (with spring attached) and the chain is no longer grinding the case. Clearly wear/condition of the rubber matters including deep divots into the rubber which allows the chain to ride deeper into the sprocket allowing more slop/slack. I'm going to buy another a torsion spring, so I look forward to the added tips. I'll install it and put the same force gauge on it to see what pressure it's pulling. Again, I don't think the difference of 7.25 lbs vs. 5.25 lbs (small vs. large spring) matters very much. What really matters is slack in the system--especially if you're riding hard. It'll be interesting to see with proper adjustment how long this set of sprockets last. I never rule out defect OEM parts either. Bottom-line is constant tension is better and the torsion spring offers full RoM tension. I'm just going to have to monitor the rubber to see what if any unusual wear occurs. Best regards - Brian

> > Several considerations: > > Sprocket and chain wear - a properly tensioned system shows less

wear

> in my experience. > > Do the current spring setups cause excess wear to the system,

possible

> due to excess tension? Again - this hasn't shown up. > > Only a loose system seems to allow the chain to contact the case. > > Detail and experience below. > > I measured the spring stretch on a few fairly new (3 miles to 500 > miles, pre 2008) motorcycles, with the factory spring still in

place.

> Knowing the wire diameter, number of coils, etc, one can come up

with

> a close guess at the initial tension. One doesn't know how much wear > the Kawasaki engineers expected immediately - this would affect > tension early in the bikes life. I'm personally not sure they

thought

> about it much. I've purchased all the various spring sizes, back to > the 600. The spring wire got larger with every change. > > I can tell you all the spring install recommendations I make are

based

> on what I've learned, and none will cause engine damage. From a > practical point, if they did, I'd know about it by now. > > I've know been into more than 300 engines at tech days or one-on-one > in my shop. Based on this experience, I'd say a properly tensioned

(or

> de-slacked) balancer system shows less wear , as evidenced by less > travel of the balancer lever/doo. I purchased a couple of very used > engines a couple of years ago, one of which had been to a tech day > about 30K miles before. This engine had my lever and the longer

spring

> in it. It still had some tension of the spring. The lever did not

move

> when the bolt was loosened, or move appreciably when tapped with a > screwdriver handle on the right side (in case it was stuck to the > inner engine case). The lever just doesn't show much movement, > indicating wear in the balancer system, when everything is properly > set up. > > I've measured several balancer chains. All of them were within the > wear limits no matter how many miles. I know some people have > advocated replacing the chain and sprockets as a matter of routine

at

> about 30K miles. I've always disagreed with that, as the sprockets > seems to be the parts showing wear. I really don't think the

sprocket

> wear (the rubber) is a big cause for concern. > > I've seen evidence of the chain hitting the cases in a couple of > places. In every case in my experience, the chain was not properly > tensioned at the time - it was loose. In the past, I've removed some > of the aluminum where the chain runs close to the idler sprocket.

This

> doesn't hurt anything structurally. Even when everything is masked > off, a fair bit of aluminum can end up in the oil, so a couple of > flushes would be a good thing. The amount of wear created by the

chain

> rubbing at this lower point with a properly tensioned system has

often

> been discussed, but no hard data exists that I'm aware of. At

several

> tech days I did slide a feeler gauge in between the chain (after the > upgraded lever and spring was installed) and there was .020 to .030 > clearance. I think that's the most data that was ever gathered, at > least that I know of. > > I know of some people that experimented with other spring setups, as > when Jake flipped the spring lever 180 and re-routed the spring.

With

> the amount of stretch there, a bunch more tension was put into the > system. I never heard of a problem there with the tension - I know

of

> one spring breaking at some point. I never bothered to calculate the > tension involved when one did that. I knew it was more than I'd want > to use - but I never heard of it damaging the engine. > > The torsion spring is captured on install, and has a longer

adjustment

> arc. There's a couple of tricks that I'll be incorporating into the > install instructions in the next few days. > > With the extension spring setup there will always be a little extra > slack in the system, depending on how much play there is between the > balancer lever and the idler shaft. This is because the extension > spring pulls on the linkage, rather than directly on the adjustment

lever.

> > all the best, > Mike >

Wilsons Sandbox

spud gun camoflauged as a tool tube, where to mount it though?

what to doo next? replaced all 3 gears...no more slack'in

what to doo next? replaced all 3 gears...no more slack'in

what to doo next? replaced all 3 gears...no more slack'in

what to doo next? replaced all 3 gears...no more slack'in

what to doo next? replaced all 3 gears...no more slack'in

what to doo next? replaced all 3 gears...no more slack'in

what to doo next? replaced all 3 gears...no more slack'in

what to doo next? replaced all 3 gears...no more slack'in

what to doo next? replaced all 3 gears...no more slack'in

what to doo next? replaced all 3 gears...no more slack'in