Jump to content
Sign in to follow this  

Seemingly common won't start!

Recommended Posts

Any help or ideas would be greatly appreciated. I have a 2008 pro circuit kx250f. I bought this bike with approx 8hrs on new top end. The first issue I encountered was a failed stator then a failed cdi unit. After resolving the electrical issue I took the bike out and it went as good as I can remember.Responsive,powerfull and joy to ride.Then things went wrong again, the bike suddenly bogged so I stopped the motor. As I looked down I could see that some oil had come out of the stator cover and the breather pipe also smoking a little.My first thoughts where maybe I put too much oil in the motor.Also I'm embarrassed to say I didn't put the stator gasket back on after fitting new stator. The bike will not kick start at all now. It will bump but seems boggy but feels like I could open the throttle and overcome it, but I don't want to risk doing anymore damage. I've checked timing which appears spot on. I've put a new plug in,also drained and filled oil back to correct amount. I'm not sure what to do/try next? Any ideas would be welcome.

Share this post


Link to post
Share on other sites

Beat thing to do at the moment is to start stripping the top end of the bike and check out your cylinder walls and piston and rings. I have a friend with a 2011 CRF250R that had the same problem. It wouldn't kick over buy if we pushed started him it would fire up. And when they stripped it down they found that the cylinder wall was scored and that they were losing all the compression due to how bad it was. So strip the head off the bike and make sure to take lots of pictures and post them as you do that.

Share this post


Link to post
Share on other sites

So it's possible the top end is done after about 15 hrs of light use?

i don't really see it being toast after 15 hours but the previous owner could have bag the bike hard. But for your sake I'm hoping that I'm wrong and that your top end is fine so that you don't have to dump a bunch of cash into the bike.

Share this post


Link to post
Share on other sites

Yeah I see your point, the thought has crossed my mind. Do these symptoms like oil coming out of breather tube point to top end troubles. Or is it the fact the bike won't kick start?

Share this post


Link to post
Share on other sites

Yeah I see your point, the thought has crossed my mind. Do these symptoms like oil coming out of breather tube point to top end troubles. Or is it the fact the bike won't kick start?

i don't think that the oil coming out of the breather tube would lead to top end troubles.

Share this post


Link to post
Share on other sites

Beat thing to do at the moment is to start stripping the top end of the bike and check out your cylinder walls and piston and rings. I have a friend with a 2011 CRF250R that had the same problem. It wouldn't kick over buy if we pushed started him it would fire up. And when they stripped it down they found that the cylinder wall was scored and that they were losing all the compression due to how bad it was. So strip the head off the bike and make sure to take lots of pictures and post them as you do that.

 

OP... Before you start taking things apart, do a simple compression check to see where your at.

Share this post


Link to post
Share on other sites

i don't think that the oil coming out of the breather tube would lead to top end troubles.

Oil blowing out of the overflow tube (if not filled with a crazy amount to much of oil) is pretty typical of a worn cylinder.....Allows blow by. This in turn pressures the bottom end and more pressure comes out the tube than usual which is why it carries oil. 

A bike, and especially a honda 250f, if it'll push start and wont kick start thats a tell tale sign of a valve problem. 

Share this post


Link to post
Share on other sites

Hello and thanks for asking. I'm taking the bike to a local bike mechanic who a friend has recommended today. He with do a compression/leak down test first then go from there. He says it could be a number of things such as head gasket,broken seals or as you say worn piston. Eiether way it has to be done. Just disappointing that it's happened with apparantly low hours on the bike.

Share this post


Link to post
Share on other sites

Ok, I took the buy to a mechanic recompense by a friend. He did a compression test which ended up showing 60psi. He basically said that the rings are worn and that it's a possibility that when the oil was pressed out the breather tube a crank seal or seals could have been blown. I'm a little dissapointed but I guess it's the nature of the beast. Any way he's gonna strip the motor and repair for around 320 US dollars. Can you guys give me a honest answer. How many hours can I expect to get from my kx250f when this work has been done? I'm new to fourstrokes I take maintance seriously and I wouldn't say I ride the bike hard.

Share this post


Link to post
Share on other sites

Ok, I took the buy to a mechanic recompense by a friend. He did a compression test which ended up showing 60psi. He basically said that the rings are worn and that it's a possibility that when the oil was pressed out the breather tube a crank seal or seals could have been blown. I'm a little dissapointed but I guess it's the nature of the beast. Any way he's gonna strip the motor and repair for around 320 US dollars. Can you guys give me a honest answer. How many hours can I expect to get from my kx250f when this work has been done? I'm new to fourstrokes I take maintance seriously and I wouldn't say I ride the bike hard.

honestly there's no answer. I've seen guys get any were from 2hours to 50/60 hours. You're probably gonna get somewere around 20-30 if I would guess.

Share this post


Link to post
Share on other sites

First a compression of 60 is not alarming, especially if the bike was cold, in which case 60 would be perfectly fine. 15 hours on a new top end is ridiculously low unless you are racing at a high level. If you ran the bike out of oil I could see where a top end tear down might be warranted. Is that what happened? Smoke from the breather would certainly be consistent with that. Even so, I would strongly consider filling the thing up with oil and running it. Any damage, if it was significant, is already done. I highly doubt any seals are blown. I doubt there is any damage at all.

Share this post


Link to post
Share on other sites

First a compression of 60 is not alarming, especially if the bike was cold, in which case 60 would be perfectly fine. 15 hours on a new top end is ridiculously low unless you are racing at a high level. If you ran the bike out of oil I could see where a top end tear down might be warranted. Is that what happened? Smoke from the breather would certainly be consistent with that. Even so, I would strongly consider filling the thing up with oil and running it. Any damage, if it was significant, is already done. I highly doubt any seals are blown. I doubt there is any damage at all.

I would say I lost about 300ml of oil out the breather tube and stator cover. So really speaking I should try bumping it again and see how it goes?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×