could use some help plz

ofnarace · #1 10-05-2009, 12:15 PM

I recently got a 98 cr 250. When I rode it home I didn't notice any probloms but over the weeks I started to when the bike warms up (not idling warmed up but rode warmed up) it has a idling problom it idles normal for a second then climbes up and surges. I also noticed that I can't ride ata constint speed you can hold it haif throtle and it'll speed up and slow down a lot I have heard crank seals and I have heard carb just wondering if any body has any ides

MXtras · #2 10-05-2009, 12:25 PM

Surging is normally a tell-tale sign of a bad crank seal (or other intake tract leak or deficiency).

Check your headpipe seal and seal collar, too. Intake leaks can come from the exhaust on a 2-stroke (reversion of exhaust gas, pressures. Long story).

Scott

ofnarace · #3 10-05-2009, 02:30 PM

Well I'm going to the hardwear store now to make a tester for the bottom end but how do I test the header seal just by look our is their a way to test it like the bottom end

MXtras · #4 10-05-2009, 03:31 PM

Visual is usually sufficient - I remember those older Hondas had a bad habit of breaking a seal collar at the cylinder. Something to investigate as I am not too up on the specifics of Hondas.

Another way would be to seal the end of the pipe (remove silencer) and include the pipe in your leakdown test.

Scott

ofnarace · #5 10-05-2009, 08:34 PM

Thanks I well look that over good but I was also wondering how much air if any is aload throu the power vale linkage ill pulled the cover cous I was getting excesive air throu the.crank breatheir so I pulled the cover and when I spary it with wendex it bubbls prety bad

json · #6 10-06-2009, 09:07 AM

If it's leaking through the power valve linkage, I had that same problem. Here is a link to that thread:

Leakdown test help

Once I greased and moly'd my linkage, my leak went away.

ofnarace · #7 10-06-2009, 12:31 PM

Thanks ill give that a try and see what happens. I'm going to chang my crank seals any ways since I'm in their. On a diffrnt note I noticed that I have a reed vavle that is out of specs could that cous any probloms that I'm experincing

MXtras · #8 10-06-2009, 01:42 PM

A non-sealing reed could cause irratic idle, yes.

Scott