re[2]: [dsn_klr650] oil consumption?
Posted: Wed Oct 08, 2014 2:38 pm
#ygrps-yiv-412064529 blockquote.ygrps-yiv-412064529cite {margin-left:5px;margin-right:0px;padding-left:10px;padding-right:0px;border-left:1px solid #cccccc;} #ygrps-yiv-412064529 blockquote.ygrps-yiv-412064529cite2 {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-412064529 .ygrps-yiv-412064529plain pre, #ygrps-yiv-412064529 .ygrps-yiv-412064529plain tt {font-family:monospace;font-size:100%;font-weight:normal;font-style:normal;} #ygrps-yiv-412064529 {font-family:Tahoma;font-size:12pt;} #ygrps-yiv-412064529 .ygrps-yiv-412064529plain pre, #ygrps-yiv-412064529 .ygrps-yiv-412064529plain tt {font-family:Tahoma;font-size:12pt;} 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 [b]From:[/b] DSN_KLR650@yahoogroups.com [b]Sent:[/b] Wednesday, October 08, 2014 10:34 AM [b]To:[/b] DSN_KLR650@yahoogroups.com [b]Subject:[/b] [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.