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]
I do find that many posts are taken as being more strongly phrased than intended. This is a very interesting subject but I haven't seen sufficient data to point us to any solid solutions to a single cause. One of the qualities of this group which I value is the consideration and focus on what is proven. Engine braking places something like 30 inches of atmosphere onto the intake and combustion chamber, almost a perfect vacuum. Another way to visualize this is that there is almost 15 PSI trying to force oil and crankcase gasses past the rings, even if one considers a static condition. In fact, the inertia of the oil droplets and certainly that of the oil film on the cylinder wall produces an effect which is exponential. Someone with a bigger diploma than my mechanical repair and power engineering may be able to offer some quantitative measure but it will certainly be equivalent to putting the oil into a pressure washer and directing it onto the bottom of the rings. I think Paul Westman's work has shown that the KLR engine is in a similar state to that of a insert bearing V8 with badly (very badly) worn main bearings so that there will be a large amount of oil on the cylinder walls which greatly challenges the oil control problem. Add to that, high RPM and high vacuum, as you referenced, and no wonder they burn oil at times. What truly amazes me is that they don't all burn a lot more oil. The oil return holes in the back of the oil ring groove and those in the oil transfer groove below the oil ring are smaller than seems to be prudent when compared with some other engines which are not chronic oil burners so I have tried and suggested reaming the holes a bit but don't know the effect. That they burn oil under deceleration is not surprising. What we have is basically a open cylinder 327 Chev and one should simply consider how one of those will fare if cruising at 5,000 RPM.