I'm going to suggest the following to Motorad and see what they thinkfound on ADVrider)
"Before I threw in the towel on the KLR, I'd try one simple at home application...an automotive PCV valve in the breather hose from the engine to the airbox. I've posted this fix a couple of times before on this forum and have posted a couple of pics of the final product. It's easy and cheap.
The idea is that the KLR has crankcase pressure issues at higher rpms. The introduction of a PCV valve in the breather hose induces a slight vacuum or at least a more neutral crankcase pressure at these higher rpms. I've had 4 KLR 600/650s over the years. Both 650's were fairly heavy oil consumers at cruising speeds of 5000 rpm or more and in cases where lots of revs were applied while riding off road. This was not a compression issue. It was an oil control issue, probably ring related. That may sound odd, but if the engine has some high or unusual crankcase pressure characteristics at certain points in its operation, the oil can be pushed past the oil and compression rings without producing visible smoke or fouled plugs.
I'm no engineer by any means. Over on KLR World, some very knowledgeable folk came up with this concept. One of them was KLRCary who worked for Schnitz Racing...same guy who helped develop the 685/705 big bore KLR kit. Cary was recently killed in a motorcycle accident. I was skeptical of this idea, but for less than $15 it was worth a try. I saved my OEM breather hose and built mine out of rubber elbows and heater hose from my local auto parts store...a cleaner application IMO. I also used a solid steel PCV valve that fits within my hose setup instead of the stamped model used in the original setup they made, which can apparently be a bit noisy. They've also come up with a reasonably priced Mercedes one-way valve now that might be even better. I'd suggest going to KLR World to read the multi-page writeup on this. It excellently explains the dynamics of the whole application. I have a lay person's theory that one problem with the stock setup is the ridiculously small airbox inlet hole for the OEM breather hose. The other eye-opener was understanding the concept of inducing vacuum into the crankcase of high performance engines and the results on both performance and oil control. While the KLR650 is hardly your 4-second NHRA beast, the concept may have some application to many internal combustion engines...especially those with oil consumption and crankcase pressure issues.
What happened after I installed mine?...at least 2/3 less oil consumption under all conditions. Yes...at least 2/3. It might be even a little more, but I want to remain conservative on this and not spout some kind of unrealistic expectation by others. This experiment will take less than $15 worth of parts and doesn't require the removal of the airbox or carb. The hardest part is opening up the breather inlet hole on the airbox, but some very clever methods were developed by some of the members on KLR World. This is one mod that is cheap, easy, and worth a try."
it's not a bad thing till you throw a KLR into the mix.
those cheap ass bitches can do anything with ductape.
(PostalDave on ADVrider)
I think Woodamn has done the PCV
the one on mine is a bit noisy at idle but that's hardly a big issue - its not exactly a stealth machine.
I also notice on both klrs that the air filter has 'splooge'' on the air filter by the crank case breather entry point on the air box. Much less on the 685 but still noticeable.
if your 'fixed' one is giving problems Pete - I hope the guy I sold my 'fixed' one to is getting on ok.
To ramble a bit further, how many balancers does the KLR have? The LC4 only has one. My Triumph triple only had one (primary and secondary balanced 120 degree crank, with a rocking couple along its length), but the fours had a second.
If there are two, then removing balance weight from the balancer so it was left to drive the water pump may not add as much vibration as first thought. Although I would think that if the doo is suspect, then adding vibration won't help it. I agree that too much tension is not necessarily a good thing, and could cause premature wear.
Cheers,
Colin
Originally Posted by Steve McQueen
It might just be easier to go buy a KTM
Then you won't have to worry about doohickies or high oil consumption at all
Although I am getting a little concerned about the oil usage of my 640, I'm having to give it a 200ml top up between services now & the damn things only done 75 000 km
Clint
No I haven't done it but I have a pcv valve somewhere in the shed ready to do it.
vacuum in the crankcas does help with horsepower, it is a good side effect of dry sump pumps used in a lot of race and drag engines, They use up to 5 stage pumps that create so much vacuum that some guys fit the seals backwards.
Actually thought that the oil under pressure went out through the breather and got fed back through the engine.
Mine uses a bit but I also suspect that it finds its own level but am too scared to prove this point so keep putting oil in.
I mentioned vegetables once, but I think I got away with it...........
one day, young man, you'll be old enough to appreciate a KLR
doohickies and such add character - like beauty spots
actually a 690 adventure would be the only bike that could seriously temp me from a klr - I'm happy to wait a couple of years and see how they pan out (and save - save - save - I'm sure they'll be near $20k)
Wonder if KTM will still be building bikes in 20years, let alone basically the same model...
it's not a bad thing till you throw a KLR into the mix.
those cheap ass bitches can do anything with ductape.
(PostalDave on ADVrider)
Sure they'll be building bikes in 20 years. They've been building bikes since 1953 - nearly a decade longer than Kawasaki.
The LC4's been around for 15 years, but they had the sense to tweak it as the years went by. Heck KTM don't even wait for the next 'model year' to implement changes, the bikes steadily evolve continuously. I like that approach better, somehow.
Cheers,
Colin
Originally Posted by Steve McQueen
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