Two Stroke Motocross

Two Stroke Motocross Forum => Technical => Topic started by: falk_ben on October 29, 2012, 02:46:54 AM

Title: Newbie few minor problems on new YZ 250 '04.
Post by: falk_ben on October 29, 2012, 02:46:54 AM
Hi Guys,

New to 2 strokes so I thought I'd join for a bit of guidance!

Just bought a YZ 250 '04 plate. Loved my mates CR 250 '07 so the 2 Stroke bug clawed back childhood memories(twos up hitting powerband through fields on older teens bikes wearing t-shirts but no helmet). Owned a CRF 450 R for 18 months before my YZ but I don't miss it!

Just checked over my latest shipment to the Falkland Islands and it's not a bad bike but requires abit of attension!

Starts and runs OK, quite surprised at the gearing being 14/46( a little tall). It's got a lot more go than my CRF!

My concerns are low water in rads, trans oil milky grey, and the shraider valve has snapped off my shock! I guess my water pump seal has failed? Can I get the valve? looks like they are replaceable. Does it get filled with air or nitrogen?

I wonder if my suspension is standard too? There are stickers with Pro Action 3 stage incremental! Does this mean they have been re-valved?

Great stuff on here

Ben. :)
Title: Newbie few minor problems on new YZ 250 ''04.
Post by: factoryX on October 29, 2012, 11:38:46 AM
Sounds like the seal failed, the valve can be replaced, and nitrogen for the refill.
Title: Newbie few minor problems on new YZ 250 ''''04.
Post by: arnego2 on October 29, 2012, 11:46:54 AM
Sound like you need a new water seal of the water pump shaft. Maybe also the shaft. Did you look up the piston? When buying a used bike that is the first thing I could do. The shock you could repair it with a new shredder valve. It happened to me and I used a car tire valve. So far it is OK I think on the YZ250 you can change the valve anyway. The shock uses nitrogen 140psi is stock, I use 150psi.   

It is quite easy to do all the work yourself. Top end, Water pump shaft seal ( maybe also the shaft) plus the shredder valve you looking at about 4 to 6 hours. 
Title: Newbie few minor problems on new YZ 250 ''''''''04.
Post by: falk_ben on October 31, 2012, 02:14:43 AM
Thanks alot for the help.

I can remember changing the waterpump shaft on my crf, so i guess it's the same.

Why did you charge 150psi instead of 140psi?

Are my Pro Action suspension standard? I thought they would be KYB. If so would fork seal part numbers be different?

Can't wait to ride this beast  ;D!

Title: Newbie few minor problems on new YZ 250 ''''''''''''''''04.
Post by: arnego2 on October 31, 2012, 11:39:15 AM
I read about benefits of the higher charge, hard to tell if they are true, before I had hardly 70psi in there.
As for you suspension I'd give the company a call.
Title: Newbie few minor problems on new YZ 250 ''''''''''''''''''''''''''''''''04.
Post by: msmola2002 on October 31, 2012, 12:37:04 PM
Pro Action have probably just revalved the suspension.

Your seals should be the same.