All Things Moto! Dirtbike Forums

Go Back   All Things Moto! Dirtbike Forums > Dirt Bike - ATV - Suspension Forums > 2-Stroke Dirt Bike Forums > 2-Stroke Dirt Bikes - Honda

Reply
 
LinkBack Thread Tools
  #1  
Old 05-15-2011, 07:19 PM
Beginner Class
 
Join Date: Dec 2010
Last Online: 08-08-2011 08:30 PM
Location: Whitby Ontario
Posts: 18
Default 98 CR250 high idle Need help

     

98 CR250. Entire motor was rebuilt. Crank, replated cylinder, piston, tranny, clutch, clutch basket and rebuilt car. When I'm riding the bike and rip on it its fine. When I let off the throttle and pull in the clutch the idle is high and does not come down until I release the clutch. Is it sucking air? When the bike is sitting still I can rev it up and the idle comes back down to normal the way it should. Yes the power jet in the carb is working. I did not replace the stock reeds in it. they are in perfect condition. FMF fatty pipe. Also it does seem to be running warm. I do see coolant dripping out the overflow when I sit for a tiny bit. This motor was just done over the winter and has about 2.5 hours on it. Any ideas on what i could try or look for???
Reply With Quote
  #2  
Old 05-17-2011, 08:40 AM
beont's Avatar
Beginner Class
 
Join Date: May 2010
Last Online: 09-25-2011 03:52 AM
Location: Greece
Posts: 21
Default

My cr250 98 is dripping coolant fluid every time i fill it up but it stops after a 80ml leak. Dont worry about the fluid.
I used to have the same problem with the idle. It was sucking air form the gasket between cylinder and crankcase without any leak at all. the nuts were tighten more than service book specs but still was sucking air. I took it apart again and noticed that the screws which came from the crankcase were loose, I took 2 nuts and tighten the scrws on crankcase , did the same for every screw on the cylinder cap also. Then I reinstall everything with a small film of glue. Working fine for 1 year. But before everything check for any gas-oil leaks underneath crankcase (there is a small overflow hole there clean it up if blocked)
Reply With Quote
  #3  
Old 05-17-2011, 02:05 PM
Beginner Class
 
Join Date: Dec 2010
Last Online: 08-08-2011 08:30 PM
Location: Whitby Ontario
Posts: 18
Default

Thanks for the help. I'll check that out this weekend. If I spray brake cleaner around the area should the idle increase if there's a leak? I also used two intake gaskets. One between the carb and boot and the other for the boot and cylinder. Honda only calls for one at the cylinder and boot. Would I use silicone with the gasket? It only does that after I get into the gas under load. Other then that it runs mint.
Reply With Quote
  #4  
Old 05-18-2011, 02:21 AM
beont's Avatar
Beginner Class
 
Join Date: May 2010
Last Online: 09-25-2011 03:52 AM
Location: Greece
Posts: 21
Default

these 5 screws of mine were loose

air filter - screw - air boot - BAND - carb - BAND - rubber pipe - BAND - reed - reed gasket (4 screws) - cylinder Mine is like yours too.
And you are right honda has only one! there 2 of them.

Problems usually occur when the engine is hot. recheck intake system and carb.
Check your reeds.
Check if the power valve is working correctly L - H. (my guess is that your problem is here)
Then yes try brake cleaner and start checking cylinder - piston size - rings....
do not apply silicon on head metal gasket just a small amount on cylinder crankase gasket wont harm.
inform me about the results
Reply With Quote
  #5  
Old 05-18-2011, 07:18 AM
Beginner Class
 
Join Date: Dec 2010
Last Online: 08-08-2011 08:30 PM
Location: Whitby Ontario
Posts: 18
Default

The power valve is working properly but I did read on here a while ago that air can come through it if you pressure test it. But yes your right it does do it when the engine is hot. I'll look at it on the weekend and let you know if I find the problem.

About the coolant. This is normal on your bike too? When I take the cap off you can almost see the rows where the coolant travels. So I'd say about 1/2 down the top tank. Is the bike over heating or do I need a new rad cap or this is expected?
Thanks for the help.
Reply With Quote
  #6  
Old 05-18-2011, 07:54 AM
beont's Avatar
Beginner Class
 
Join Date: May 2010
Last Online: 09-25-2011 03:52 AM
Location: Greece
Posts: 21
Default

It is common to these old models to loose some fluids after filling them up, you might loose some when its idle is high and bike stands still or playing with neutral with high rpm and no speed. Note that you have one radiator instead of 2 that newer models have.
I run my bike with 1inch bellow cap fluid lever for over a year every time i fill it up its leaking immediately. I guess old machines cant hold themselves they have to pee. These bikes are made to handle a little overheating forget it until it gets serious
Reply With Quote
  #7  
Old 05-20-2011, 08:26 PM
Beginner Class
 
Join Date: Dec 2010
Last Online: 08-08-2011 08:30 PM
Location: Whitby Ontario
Posts: 18
Default

I pulled the plug and it seems to be running lean. The plug is very clean and slightly white in color. Not the tan color that you want. The carb is set to the stock settings that the manual call for. What to try now?
Reply With Quote
Reply

  All Things Moto! Dirtbike Forums > Dirt Bike - ATV - Suspension Forums > 2-Stroke Dirt Bike Forums > 2-Stroke Dirt Bikes - Honda


Thread Tools


Similar Threads for: 98 CR250 high idle Need help
Thread Thread Starter Forum Replies Last Post
1997 cr250 very high idle after one ride???? ericmb79 2-Stroke Dirt Bikes - Honda 2 08-23-2010 11:00 AM
cr 134 high idle need help bundyho1 2-Stroke Dirt Bikes - Honda 4 03-25-2010 01:32 PM
High idle, surging and spitting oil- 1999 Cr250 gavd 2-Stroke Dirt Bikes - Honda 3 10-12-2009 05:08 PM
2000 CR250 HIGH IDLE ctroger24 2-Stroke Dirt Bikes - Honda 5 12-12-2008 01:16 AM
2002 cr250 High Idle? kitsrider 2-Stroke Dirt Bikes - Honda 2 10-20-2008 09:10 AM


All times are GMT -6. The time now is 03:25 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright ©2002-2017, JDub Consulting, Inc. All Right Reserved.