Jump to content

2006 CR 250R Won't Start

Recommended Posts

10 hours ago, frdbtr said:

My 06 with a modified head cut for pump premium fuel will blow 210 psi.  I would assume a non modified 06 cr250, it should blow at least 180 if not more, which means that your motor is blowing 100psi low.  IMO that is your starting issue.  How does your piston look?  Excessive blowby? 

 

2E76DB3A-8032-4122-98E1-3B417E72ACBC.jpeg

A2C020FB-B1FA-42C5-A6BE-C7766CD43595.jpeg

53D767BB-40AD-45E4-8D50-614A15D6E6FA.jpeg

6B9843FB-EDD2-4C7B-AA5B-5EFAE8F2BA0F.jpeg

Share this post


Link to post
Share on other sites

That piston needs a lube hole drilled where it meets the exhaust port bridge. Otherwise fine.

Share this post


Link to post
Share on other sites

RING DING DING .. DING ..... DING DING DING .... RING .. DING DING DING ... DING DING ... RING DING DING DING!!!!

Somebody's riding tomorrow LOL

 

I still have some unanswered questions, the bizarre resistance readings in the wiring harness that I only saw there and not across any of the components.  What is the published, engineered compression supposed to be for a new top end.  Why could I not get a compression test to hold after the rebuild, it was leaking off slow at first, I barely caught something over 100, then I cleared it (released the pressure) and I couldn't get it to hold pressure anymore.  It was threaded in tightly and everything else appeared fine.  And whatever other questions I've already forgotten about by now.  Anyways, I could care less right now, let's go ride!

Thanks to all for your input, this was a great exercise and learning experience for a new 2T rider.

 

  • Like 1

Share this post


Link to post
Share on other sites
1 hour ago, Mike_80 said:

RING DING DING .. DING ..... DING DING DING .... RING .. DING DING DING ... DING DING ... RING DING DING DING!!!!

Somebody's riding tomorrow LOL

 

I still have some unanswered questions, the bizarre resistance readings in the wiring harness that I only saw there and not across any of the components.  What is the published, engineered compression supposed to be for a new top end.  Why could I not get a compression test to hold after the rebuild, it was leaking off slow at first, I barely caught something over 100, then I cleared it (released the pressure) and I couldn't get it to hold pressure anymore.  It was threaded in tightly and everything else appeared fine.  And whatever other questions I've already forgotten about by now.  Anyways, I could care less right now, let's go ride!

Thanks to all for your input, this was a great exercise and learning experience for a new 2T rider.

 

Well what did you do to get the bike running ?

Share this post


Link to post
Share on other sites
7 hours ago, Dklassen said:

Well what did you do to get the bike running ?

Rebuilt the top end, it was the low compression.  Which reminds me, add another question to the list of unanswered: Why did I lose that much compression so fast?  Or is this normal after 12 hours of run time for a 2 stroke?

I've always scoffed at what the service manual says on when to replace the piston and ring (7.5 hours or every 3 races) because to me that just sounds ridiculous, not to mention a serious threat to my wallet.  I look at a lot of the items on the entire maintenance schedule and think, dang if I did all of these replacements every time it said on here I'd be broke and living on the streets, not to mention would never get the bike out of the garage.  But after this little episode I'm wondering am I going to have to do this top end every 12 hours now?  Well the data here leads me to believe something isn't right, here's the history on the top end rebuilds:

1st = 20.0 hours usage (shut down as scheduled/preventative, no issues)

2nd = 23.0 hours usage (shut down as scheduled/preventative, no issues)

3rd = 29.3 hours usage (shut down past scheduled but no issues)

4th = 12.4 hours usage (shut down as reactive, would not start)

 

Share this post


Link to post
Share on other sites

That is not normal life for piston and rings. Something went wrong. But I see you were using the single ring piston. I have no experience with that. Did you install the piston with the mark on the ring facing up?

Share this post


Link to post
Share on other sites
1 hour ago, Mike_80 said:

Rebuilt the top end, it was the low compression.  Which reminds me, add another question to the list of unanswered: Why did I lose that much compression so fast?  Or is this normal after 12 hours of run time for a 2 stroke?

I've always scoffed at what the service manual says on when to replace the piston and ring (7.5 hours or every 3 races) because to me that just sounds ridiculous, not to mention a serious threat to my wallet.  I look at a lot of the items on the entire maintenance schedule and think, dang if I did all of these replacements every time it said on here I'd be broke and living on the streets, not to mention would never get the bike out of the garage.  But after this little episode I'm wondering am I going to have to do this top end every 12 hours now?  Well the data here leads me to believe something isn't right, here's the history on the top end rebuilds:

1st = 20.0 hours usage (shut down as scheduled/preventative, no issues)

2nd = 23.0 hours usage (shut down as scheduled/preventative, no issues)

3rd = 29.3 hours usage (shut down past scheduled but no issues)

4th = 12.4 hours usage (shut down as reactive, would not start)

 

I wonder if the electrical testing you did fixed a bad connection? I say this because I don’t believe low compression alone caused the non starting. I don’t know how big you are or how hard you ride but even racing my bike I wouldn’t rebuild until after 30 hours. (I’m on my third last Gen CR250 so I know a bit about the bike) Since there was evidence of dirt and water in the engine I believe that’s what caused the premature wear. Once that air box is sealed off it should be much better. 

 Carry on!

Share this post


Link to post
Share on other sites
2 hours ago, Keith72 said:

That is not normal life for piston and rings. Something went wrong. But I see you were using the single ring piston. I have no experience with that. Did you install the piston with the mark on the ring facing up?

I’m always very diligent about these details and so while I can tell you yes I always install it with marking facing up, I don’t specifically remember.

 

2 hours ago, Dklassen said:

I wonder if the electrical testing you did fixed a bad connection? I say this because I don’t believe low compression alone caused the non starting. I don’t know how big you are or how hard you ride but even racing my bike I wouldn’t rebuild until after 30 hours. (I’m on my third last Gen CR250 so I know a bit about the bike) Since there was evidence of dirt and water in the engine I believe that’s what caused the premature wear. Once that air box is sealed off it should be much better. 

 Carry on!

So then let me add a little more to the story now, I actually WAS able to get it to fire a few times but I had to kick the hell out of it and give it lots of throttle.  It would die immediately unless I held the throttle open slightly.  Keep in mind I put 0.2 hours (anywhere from 6 - 12 min) on the bike just from kicking it, and only got that to happen maybe 3 times.

Remeber I saw good spark before I started any electrical testing, so I’m still not sure that had anything to do with it.  I might replace that coil though later.

Share this post


Link to post
Share on other sites
2 hours ago, Dklassen said:

I wonder if the electrical testing you did fixed a bad connection? I say this because I don’t believe low compression alone caused the non starting. I don’t know how big you are or how hard you ride but even racing my bike I wouldn’t rebuild until after 30 hours. (I’m on my third last Gen CR250 so I know a bit about the bike) Since there was evidence of dirt and water in the engine I believe that’s what caused the premature wear. Once that air box is sealed off it should be much better. 

 Carry on!

:thumbsup: I also think it was electrical in some manner. My CR is pushing 80 Hours on a single ring Wiseco Pro Lite top end. Great comp and usually a one to two kick starter.

Share this post


Link to post
Share on other sites
2 hours ago, Piney Woods said:

:thumbsup: I also think it was electrical in some manner. My CR is pushing 80 Hours on a single ring Wiseco Pro Lite top end. Great comp and usually a one to two kick starter.

What are you calling great compression?  I bet it’s significantly higher than 83.

I’ll continue to track this after I replace the coil later, but that’s really the only electrical component I can confirm may be adding to this problem.

 

Share this post


Link to post
Share on other sites

:thumbsup: Remember, I'm here for you, money in hand,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Edited by Piney Woods
  • Like 1

Share this post


Link to post
Share on other sites
8 hours ago, Keith72 said:

That is not normal life for piston and rings. Something went wrong. But I see you were using the single ring piston. I have no experience with that. Did you install the piston with the mark on the ring facing up?

All 05-07 cr250's have a single ring piston. 

  • Like 2

Share this post


Link to post
Share on other sites
35 minutes ago, frdbtr said:

Now that you got it started, what jetting are you going with?  Did you put the JD kit back in?

Yeah JD kit back in, starting with red #3 and the 32.5 pilot.  About 10 min away from our first test.

 

  • Like 1

Share this post


Link to post
Share on other sites
2 hours ago, Mike_80 said:

Yeah JD kit back in, starting with red #3 and the 32.5 pilot.  About 10 min away from our first test.

 

Well, I hope it gets your jetting sorted.  Glad you got the bike running again.  I never even tried to jet the Mikuni, I had a PWK airstriker carb laying around when I bought my 06 and put it right on.  Eventually bought a YZ250 carb with the tps for it and the other PWK is currently on my 03.  I am a lot more comfortable jetting a Keihin is most of the reason why I did that.  JD's needles have been good to me with both my PWK's and also with the 05crf450 that I used them on.  You will have to give us a ride report once you get some seat time with this jetting setup.

Share this post


Link to post
Share on other sites
3 hours ago, frdbtr said:

Well, I hope it gets your jetting sorted.  Glad you got the bike running again.  I never even tried to jet the Mikuni, I had a PWK airstriker carb laying around when I bought my 06 and put it right on.  Eventually bought a YZ250 carb with the tps for it and the other PWK is currently on my 03.  I am a lot more comfortable jetting a Keihin is most of the reason why I did that.  JD's needles have been good to me with both my PWK's and also with the 05crf450 that I used them on.  You will have to give us a ride report once you get some seat time with this jetting setup.

I will, and I'll put it in my jetting post.  I want at least one more ride before I submit my feedback and opinions, today wasn't enough.

 

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

Reply with:


×