Hello Everyone,

New to the forums, and a relatively new Kawasaki owner.
I am having an issue(s) with my new-to-me KLX250 and am hoping someone here might be able to help me with what I am seeing.
First some background on the bike:
Bought it about 6 months ago with 5,000km on it. I've since put on about 1,000km. Bike is all stock from what I can see. Oil was clean when I bought it, and I have changed it once already. I have not dropped the bike, or is there any signs of it being dropped before me. I mainly ride off-road with it.
All was well this year, except the last ride of the season. Starting right at the start of the last ride the bike was becoming harder to start cold and would clearly burn some oil for a few moments. It would clear up, but my friends behind me would still be getting a whiff.

My concerns are:
1. Why the sudden burning of oil, although I could live with a bit of that due to it being a 16 year old bike? (compression test/tear down coming soon I suspect)
2. During what I was hoping to be a routine valve clearance check, I've noticed the exhaust cam appears to be burnt, or maybe damaged in some way. In the attached pictures a kind of "cheetah" looking spot pattern can be seen on the shaft, which seems to carry all the way through to the sprocket end, as well as up the sides of the lobes, although the lobe faces look clean, as well as the valve buckets. I don't believe the journals or races have any weird wear, but would value an opinion on that. Has anyone seen this?

I can provide more pictures if the attached aren't detailed enough. As a note, I have not done this type of work on an engine before, so this is all new to me, so please forgive me if I'm not using the correct terms here.

Thanks for your time.

 

Use inside and outside micrometers to measure the clearance between the cam and journals. Spec. = .15mm. max clearance.

Ride on
Brewster

 

Usually smoke on start up on any four stroke engine is due to oil that seeps past valve seals. The only fix is to replace the seals. It is possible to replace seals without pulling the head, using air pressure to hold the valve in place while removing the spring retainer and keepers to access the seal. Car people use that technique too. If valves have a good seal it can be done.

I have a couple questions.

• How much time was there between your last ride and the one before that?
• Are you showing scuffing inside the cam journals in the head?
• Does the engine have the automatic cam chain tensioner or does it have a manual tensioner?

Feel free to PM me on this if you wish.

 

Thanks guys for the prompt replies.

Brewster,
Thank you for the clearance specs. I will have to do some digging around town for some micrometers. Think I'll have to order them in, I just so happened to have a look at the best local store for those a few days ago while on the search for some feeler gauges, which I also didn't find.
Will start with those measurements and go from there.

KLX678,
Thanks for the tips on the valve seals. Was maybe suspecting that myself, assuming that the piston rings and cylinder bore are still good. Due to the age of the bike and the relative low mileage, I suspect it did some sitting around most of its life, so perhaps valve seals have had their day. I might pull the head to do that, so I can inspect the cylinder at the same time, after I check the cam clearance of course.

To answer your questions:
1. Probably a couple of weeks, if I remember correctly.
2. I believe the journals look good, nothing major jumps out at me as being wrong.
3. The automatic tensioner is still in place

Thanks guys

 

@Fish Sticks I don't know about your area, but here in the middle of Ohio, if I let my 250 sit for over around 2 weeks the gas in the carb starts to degrade making starting harder. My KLX650 was far worse, if the gas was over 5 days old I wouldn't even bother to try, I'd just drain the carb float bowl and get fresh gas from the tank. It would fire up virtually instantly. After a couple weeks I'd have to do the same with the 250. Gas was just crap, aromatics injected into the gas mixture would evaporate over that time, making the gas weak.

I just wanted to make sure no one either did a cam chain tightening maneuver with the OEM tensioner or overtightened a manual tensioner causing issues. The stock tensioners can go bad creating a rattling in the cam drive starting between 4000-6000 rpm eventually making the noise about all the time. Some people tell others to do a maneuver with the stock tensioner to get the chain tension tightened, a bad thing to do, possibly pulling the cams down breaking the oil film in the cam journals. Manual tensioners properly adjusted will work better, but some riders don't adjust them properly, overtightening them. That's why I asked. I don't want you to have problems due to either situation.

I hope the gas takes care of your issues. You can run with the leaking valve seals for a while if you want, it will just smoke on start up a bit. Of course winter is prime time to fix something like that though.

 

Thank you KLX678.
I agree on the gas, could very well be part of the problem with starting, once I get it back together, i will start chasing that particular issue down a bit better. Will likely do a jet kit as that seems to be a common thing to do from what I've read on the interwebs.
I am not certain if the automatic tensioner has been modified in any way. I will have to see if I can tell. I am unfamiliar with the maneuver you mention, so I'll do some research.

Thanks for the info. I will add that stuff to the list of things to check out.

 

Where you are seeing the 'cheetah', that is just a shaft in the open in the head. That is not the bearing. I don't know what caused it, but I think you're over thinking this, just clean it up and put it back together.
Were the valves in spec?
If the exh valve was tight or if the engine was run hot, maybe that caused that. When I tore mine down it didn't look like that there, it was just a black sooty uniform color. If you change your shims, set them on the loose side of the spec.
Do not run this engine without oil for 1 minute.

 

Another thought: If there's exhaust smoke during deceleration, that's an indication of leaky valve seals. Smoke under acceleration is an indication of worn rings.

Ride on
Brewster

 

You can check out information at my web site, click here then click on products to see what the 250 kit looks like installed in the bike. If it looks like that it's a manual tensioner, otherwise it is likely the OEM.

I didn't mention it, but I wouldn't be worried about the coloring on the cam in the unmachined area. If the actual journal looked like that then I'd be concerned. The cam is heat treated before grinding so the coloring just might be a bit of the remainder of that since that area isn't machined.

 

Thanks again everyone for the info.
Just waiting on the micrometers and feeler gauges to arrive so I can have some concrete idea of where things are at. Won't be until after Christmas at this point, stuff doesn't arrive until after that anyway, but I'm also going camping so it can wait a week.
Once I confirm measurements on the cam journals and valve clearance, and hopefully assuming they are within spec, I'll have to think about the next steps. Don't want to make too much of a project out of it, but I'm also having fun too.

Thanks guys.