re[4]: [dsn_klr650] oil consumption?
Posted: Wed Oct 08, 2014 9:38 pm
#ygrps-yiv-1638421095 blockquote.ygrps-yiv-1638421095cite {margin-left:5px;margin-right:0px;padding-left:10px;padding-right:0px;border-left:1px solid #cccccc;} #ygrps-yiv-1638421095 blockquote.ygrps-yiv-1638421095cite2 {margin-left:5px;margin-right:0px;padding-left:10px;padding-right:0px;border-left:1px solid #cccccc;margin-top:3px;padding-top:0px;} #ygrps-yiv-1638421095 .ygrps-yiv-1638421095plain pre, #ygrps-yiv-1638421095 .ygrps-yiv-1638421095plain tt {font-family:monospace;font-size:100%;font-weight:normal;font-style:normal;} #ygrps-yiv-1638421095 {font-family:Tahoma;font-size:12pt;} #ygrps-yiv-1638421095 .ygrps-yiv-1638421095plain pre, #ygrps-yiv-1638421095 .ygrps-yiv-1638421095plain tt {font-family:Tahoma;font-size:12pt;} The sleeve is an interference fit at the top and sits in the rubber seal and some interference at the bottom. I haven't thought to measure the amount of interference at room temperature. If you take a cylinder and run a bore gauge to see taper & out-of-round, then torque it to the head and check again, you will see that the taper and out-of-round have changed significantly. Ditto before and after heating to near normal operating temperature. That's why I am concerned about distortion and hold that it needs to be accommodated when machining. A tech friend & I did the measuring so no chance of error. IME, the bottom of the sleeve is usually a mild interference or the sleeve can't be bored as it won't stay still due to vibration. I agree about tolerances. The KLR is quite sloppy compared with newer stuff and no idea as to the metallurgy. Metals have a different expansion coefficient but various structures also expand and contract at different rates so one can be bitten on the butt if one tries to use specifications from one engine on another, but you will be very well aware of that so only adding for others' benefit. Hope it doesn't sound like I'm lecturing or explaining things to you, Fred. I'm only knocking this stuff around as I know that you are well aware of these factors. I've wondered about nicosil or chrome for a KLR cylinder but am not ambitious or wealthy enough to want to play with that stuff these days. I also like the idea of some of the composite metals like the CBR600 which appears to have some silicone impregnated aluminum in the block. That didn't work out for GM with the Vega engine but that was a long time ago. It would be fun to press in a sleeve and chrome or otherwise to see how it would work out. I recall making sleeves for another instructor's 400 Chrysler from GM diesel sleeves. Man, did the boring bar squeal doing those. 
I think that the higher temperature thermostat and by-pass is a done deal as it is standard in automotive and any of the better bikes. It has been this way for many decades. One can see the case empirically since the KLR engine has clearly been designed to operate at cooling system temperatures above 210 F. This has to be the case because the engines routinely operate in this range under normal conditions, conditions which the engineers must have intended. Combustion efficiency and engine life are improved by raising engine operating temperatures from the 160 F of the KLR thermostat and that of early automotive engines to the present 195 F. Some more modern engines operate with 210 F or 215 F thermostats for increased efficiency. The closer is the cooling system temperature to that of the average combustion chamber temperature, the shallower the thermal gradient and so less heat is lost. Less heat loss equals higher efficiency. Running the bottom of the cylinder at lower temperature than that of the top must result in distortion of the cylinder due to less expansion. This is one of the reasons why automotive and properly designed motorcycle engines (non-competition) use a thermostat by-pass system in order to circulate and so even out coolant temperature which also maintains a more even cylinder and head temperature. When discussing the issues of high RPM oil consumption with some of my engine technician acquaintances, most of them asked at what temperature the engine operates and when I mentioned that it doesn't have a by-pass, they commented that the reason for the 160 F thermostat was likely so they'd be able to keep head gaskets in them. Engines such as 2.2 & 2.5 Chrysler, which were the last I can recall not using a by-pass, were known for head gasket problems. They'd not have been able to pass emissions with a 160 or 180 F thermostat. They were a real problem in cold climates where they exhibited the same characteristics as a typical KLR in cool conditions: temperature gauge flailing up and down as the thermostat cycled. Running the by-pass evens out the engine temperature and also increases the heat sink effect so that the thermostat doesn't cycle open/closed but rather tends to vary degree of opening. One sees that right away on the dash and even more conclusively when additional sensors are stuck on the engine. If there were some conspiracy to sell things which aren't needed, all the engine manufacturers have been fooled and the spin has completely taken me in. 
Take any marine engine which runs raw water (requires low thermostat) and convert to keel cooler or heat exchanger to run 180 or 195 and see the difference in engine life and fuel consumption. Same with vehicles. Of course one can't expect a thermostat or by-pass to deal with over cooling by air flow but that's another issue which affects the KLR under colder conditions. We found the obvious solutions and broke quite a few myths when doing cold weather research in the north. Most of that points to the same on colder temperature KLR use but the temperatures are something like 100 F higher for the KLR cooling. Running the engine at a higher and more even internal temperature tightens up clearances which makes more power, better mileage and less oil consumption. Another area for investigation is that of crankcase venting and compression/pumping. Honda seem to be opening up the crankcases on their sport bikes, apparently to allow better air movement and apparently to reduce compression/pumping effort in the crankcase. This will produce more power and might reduce the amount of oil being pushed past the rings. It would be interesting to look at some KLR cases again with that in mind but I doubt that I could develop more than questions. I know that there have been claims that increasing the crankcase venting might be useful and that there have been some very "optimistic" claims for PCV valves inserted into the vent. I don't use the term "optimistic" for all claims but it is difficult to understand how one can pass much air past the tiny vent restriction in the air box. I do think that there might be something there, however. ------ Original Message ------ From: "Fred Hink" To: "GMac" ; DSN_KLR650@yahoogroups.com; "Norm Keller" Sent: 2014-10-08 2:50:02 PM Subject: Re: Re[2]: [DSN_KLR650] Re: Oil consumption?
I think that the higher temperature thermostat and by-pass is a done deal as it is standard in automotive and any of the better bikes. It has been this way for many decades. One can see the case empirically since the KLR engine has clearly been designed to operate at cooling system temperatures above 210 F. This has to be the case because the engines routinely operate in this range under normal conditions, conditions which the engineers must have intended. Combustion efficiency and engine life are improved by raising engine operating temperatures from the 160 F of the KLR thermostat and that of early automotive engines to the present 195 F. Some more modern engines operate with 210 F or 215 F thermostats for increased efficiency. The closer is the cooling system temperature to that of the average combustion chamber temperature, the shallower the thermal gradient and so less heat is lost. Less heat loss equals higher efficiency. Running the bottom of the cylinder at lower temperature than that of the top must result in distortion of the cylinder due to less expansion. This is one of the reasons why automotive and properly designed motorcycle engines (non-competition) use a thermostat by-pass system in order to circulate and so even out coolant temperature which also maintains a more even cylinder and head temperature. When discussing the issues of high RPM oil consumption with some of my engine technician acquaintances, most of them asked at what temperature the engine operates and when I mentioned that it doesn't have a by-pass, they commented that the reason for the 160 F thermostat was likely so they'd be able to keep head gaskets in them. Engines such as 2.2 & 2.5 Chrysler, which were the last I can recall not using a by-pass, were known for head gasket problems. They'd not have been able to pass emissions with a 160 or 180 F thermostat. They were a real problem in cold climates where they exhibited the same characteristics as a typical KLR in cool conditions: temperature gauge flailing up and down as the thermostat cycled. Running the by-pass evens out the engine temperature and also increases the heat sink effect so that the thermostat doesn't cycle open/closed but rather tends to vary degree of opening. One sees that right away on the dash and even more conclusively when additional sensors are stuck on the engine. If there were some conspiracy to sell things which aren't needed, all the engine manufacturers have been fooled and the spin has completely taken me in. Take any marine engine which runs raw water (requires low thermostat) and convert to keel cooler or heat exchanger to run 180 or 195 and see the difference in engine life and fuel consumption. Same with vehicles. Of course one can't expect a thermostat or by-pass to deal with over cooling by air flow but that's another issue which affects the KLR under colder conditions. We found the obvious solutions and broke quite a few myths when doing cold weather research in the north. Most of that points to the same on colder temperature KLR use but the temperatures are something like 100 F higher for the KLR cooling. Running the engine at a higher and more even internal temperature tightens up clearances which makes more power, better mileage and less oil consumption. Another area for investigation is that of crankcase venting and compression/pumping. Honda seem to be opening up the crankcases on their sport bikes, apparently to allow better air movement and apparently to reduce compression/pumping effort in the crankcase. This will produce more power and might reduce the amount of oil being pushed past the rings. It would be interesting to look at some KLR cases again with that in mind but I doubt that I could develop more than questions. I know that there have been claims that increasing the crankcase venting might be useful and that there have been some very "optimistic" claims for PCV valves inserted into the vent. I don't use the term "optimistic" for all claims but it is difficult to understand how one can pass much air past the tiny vent restriction in the air box. I do think that there might be something there, however. ------ Original Message ------ From: "Fred Hink" To: "GMac" ; DSN_KLR650@yahoogroups.com; "Norm Keller" Sent: 2014-10-08 2:50:02 PM Subject: Re: Re[2]: [DSN_KLR650] Re: Oil consumption? Let me know if I am wrong but isn t the wet sleeve of the KLR only supported at the top and the bottom support is just for centering in the cylinder? There is an o-ring seal to keep the coolant in at the bottom and to allow this sleeve to move with temperature and expansion. If this is true, I don t see how torqueing the head and cylinder is going to effect the roundness of the sleeve if it is allowed to move on it s own. The KLR is pretty old technology and through the years tolerances have tightened up significantly. An aluminum piston in a steel cylinder or sleeve is going to expand at different rates and so the piston clearances are set accordingly. More modern engines that use a Nikosil or some other coating in an aluminum cylinder are going to have more consistent expansion with an aluminum piston and therefore clearances are much tighter. It s hard to control oil usage, compression and piston life when you have a lot of clearance to start with. At least with the old school technology the pistons and cylinders were more beefy and would take a lot of wear before needing to be worked on. Modern engines with their short piston skirts and light weight parts will require much more maintenance and piston replacement but they do make more power. The KLR is good at what it does and you can t make a silk purse out of a sow s ear. I have no connection with the thermo-bob , in fact I am not convinced it is even necessary. Anytime anyone comes up with a solution to a problem that never existed just to sell a part and make money I have to wonder why.... If you like spending money and it makes you feel better then I say go for it. I would be interested in any piston measurements along with the cylinder it came from. Sometimes pistons will wear more than the cylinder and other times the cylinder can wear more than the piston. Cylinder bores or the sleeve should be round +/- a certain dimension but pistons are usually never round because of the shape a piston is made and it s expansion. Fred http://www.arrowheadmotorsports.com [b]From:[/b] DSN_KLR650@yahoogroups.com [b]Sent:[/b] Wednesday, October 08, 2014 3:10 PM [b]To:[/b] DSN_KLR650@yahoogroups.com ; normkel32@... ; moabmc@... [b]Subject:[/b] RE: Re[2]: [DSN_KLR650] Re: Oil consumption? One other thing is that in building a high performance small block Chevy engine, usually a non-factory block or a seasoned block is used. The seasoned block has been through multiple hot/cold cycles and taken it s set . Then it s bored with torque plates installed to keep the cylinder distortion the same as with heads installed. This isn t done with the KLR. I m wondering if there s different steel qualities involved allowing excessive distortion. It could also be the piston expansion rate is very different, again going back to the steel/aluminum mixture used. If they re off spec then the expansion/contraction when hot or cold will be extremely different and cause excessive oil consumption. This could fall back on a supplier standard failure, which only the manufacturer would know about. GregM From: DSN_KLR650@yahoogroups.com [mailto:DSN_KLR650@yahoogroups.com] Sent: Wednesday, October 08, 2014 2:20 PM To: Fred Hink; DSN_KLR650@yahoogroups.com Subject: Re[2]: [DSN_KLR650] Re: Oil consumption? I have checked several cylinders for size, taper & out-of-round in the normal course of work but only a few of the 30+ pistons because most were kindly shipped t me by someone who had done the replacements. IMO, there are two issues regarding cylinders in general and the KLR650 in particular. I'm outlining this, not because I think that others have not considered these issues, but rather in hopes that someone will identify faulty reasoning/conclusions on my part. A friend & I took a couple of KLR cylinders (one freshly bored by a person unknown) and checked taper & out-of-round, then used a head gasket head bolts, washer stack & nuts to torque the head bolts to specification with cylinder off the engine. We re-measured taper and out-of-round. Following this, we immersed the head (inverted) into a pot of near boiling water and measured taper & out-of-round as the head and cylinder came up to stable temperature. From this it seems clear that the cylinder distorts/changes dimensions from hot to cold. This would also relate to issues regarding the cycling of cylinder temperature due to thermostat operation because the engine lacks a by-pass passage. I think you did some work in this regards in developing an external thermostat housing and by-pass but don't recall whether you reported temperature and distortion results. If you do have numbers, I'd be very interested and appreciative. Bill Watson offers two by-pass systems, then latest uses a stock sized thermostat which I had produced in custom batches for my own experiments. His work and results are so much more comprehensive as not to be compared with my crude efforts. I have experimented with around 20 195 F thermostat and by-pass systems of my own design but feel that anyone owning a KLR is better to purchase one of the off the shelf units from Fred or Bill because I don't wish to become involved in extensive support. That all said, there are a number of issues/questions I see with regards KLR cylinders. Some of these questions have illicited anger and denial from people whom, IMO, should be open to or at least willing to defend contrary views. This seems not to be the case and some aren't talking to me. Hmmm. Check taper & out of round on any modern engine, then bolt on the head and recheck. The defense rests. This is why it is common machine shop practice to bore even heavy cast iron blocks with torque plates installed. I used to demonstrate some of these problems to automotive students when teaching in the colleges but here's an appreciation of the issues on YouTube which does a better job than I ever could: https://www.youtube.com/watch?v=Cx_DCUht-Xg So, what people are telling me is that boring an unsupported KLR650 cylinder is good practice? Maybe, but what no one has defended is: "Why does taper and out-of-round change between torqued and not torqued but you choose to bore in the untorqued condition?" If the cylinder changes dimensions, doesn't one want the cylinder to be "true" when it is on the engine? How can one bore the cylinder, then install and think it's good that dimensions change? I could be right out to lunch on this but would like to hear some evidence from someone as to why this is incorrect as it seems important. Next thing is the temperature & possible distortion issue with regards temperature....actually two issues. One issue is that the cylinder dimensions changed in the two cylinders we checked so I expect this is not unusual. High performance and premium engine work is done with the block torque plated and at operating temperature. I do know of several bike engine issues due to cylinder distortion due to the heat of honing but this hasn't gotten the attention of the machinists involved who dismiss the idea. Hmmm. Wouldn't one want the bore to be true at operating temperature as opposed to at room temperature? Again, maybe I'm off base but would like to hear the contrary defended. Second issue is that the KLR cylinder temperature varies greatly as the thermostat opens and closes which both makes the cylinder grow and contract clearances + vary cylinder temperature/dimensions from top to bottom. This is what we saw in our two tests and what I would expect. A straw poll of Thermo-Bob users on another web group indicated that everyone noticed a decrease in oil consumption and increase in fuel mileage when the higher temperature and by-pass thermostat system was installed. I'm thinking that there may be multiple causes for KLR oil consumption but we have not seen sufficient reviewed study to claim conclusions. It seems clear that: - some oil rings are faulty due to chipped/peeling chrome. - some rings were not seated or have lost seating because I was able to simply deglaze hone and the rings work fine. the piston to cylinder clearances decrease when the engine reaches operating temperature and the engine has to have been designed for clearances at above 210 F (fan switch temperature) so operating at 160 F (stock thermostat) and no by-pass has the clearances quite loose normally. - the cylinders are subject to distortion by torquing and temperature but this is not addressed, perhaps by Kawasaki in manufacture. - the cylinder is, as you stated, apparently likely to distort or be distorted. We checked a sleeve out of the cylinder for taper and out-of-round but I forgot to record so should pull one again. That, in brief, is what I think about the issue of the KLR cylinder. I make no claims to be smarter or more informed than anyone else but have more than 50 years of engine servicing and machining experience as well as formal training and certification in the field so do submit that someone needs to make a case before I can accept what appears to run contrary to both theory and practice. Love to hear what anyone else has to say. I don't care at all about being correct, I care about the truth and discovering why and where I am wrong is the best thing possible. I can post the dimensions and such from a 30+ piston study I did of KLR650 pistons if someone is interested. ------ Original Message ------ From: "Fred Hink" To: DSN_KLR650@yahoogroups.com; "Norm Keller" Sent: 2014-10-08 10:44:15 AM Subject: Re: [DSN_KLR650] Re: Oil consumption? Out of those 30+ pistons have you ever checked the cylinder for out of roundness? Eldon Carl believes (and I tend to agree with him) that some KLRs that use oil are because the sleeve on the KLR is supported at the top and bottom and nothing in the middle. This extra large hole can distort the sleeve to where it isn t round any longer and it is hard to seal a square hole with a round peg. Putting in an oversized piston in a new bore will usually cure the excess oil usage but for how long. Just because you now have a round hole and a round peg, doesn t mean it is going to stay that way very long. If fact I would guess that a big bore kit with a thinner sleeve would suffer the effects of heat distortion as quick if not quicker than the stock bore. Fred http://www.arrowheadmotorsports.com http://www.arrowheadmotorsports.com/> From: mailto:DSN_KLR650@yahoogroups.com Sent: Wednesday, October 08, 2014 10:34 AM To: DSN_KLR650@yahoogroups.com Subject: [DSN_KLR650] Re: Oil consumption? Paul Westman has done some very interesting work in reducing oil flow to the crankshaft which has reduced the oil consumption, increased fuel mileage and shown excellent oil results in oil analysis. The hypothesis seems so well supported by evidence that it may be more correctly termed as a theory. I've seen some oil rings with chipped/peeling surface which might be the issue with some bikes. The 30+ used pistons I've inspected had several examples. Another interesting case was a Gen1 which was a very bad oil burner. I pulled the top end and had the valves & seats ground because they were so pitted from the deposits. I deglaze honed the cylinder and left the rings because the end gaps were still OK. The oil consumption is back to typical, Just, FWIW. [Non-text portions of this message have been removed]