[mira_mx]

Hello,
i'm Alessandro from Italy, i'm going to become crazy about my CRF 250R year 07.
i bought this bike used, in really good conditions, it has really good performances, and it started with few kicks in any conditions.
After one year of riding, with all the right mainteinance (oil change with motul every 7 hours, oil filter every 14 hours, air filter cleaning every ride...) the bike has difficoult to start, i checked the valves clearance and i discover that the intake valves has not clearances, so they rested open...
I tried to adjust the clearance with new shims but also with the right clearance the bike did'nt start by kick but only by push.
So i changed the intake valves with a pair of proX steel valves, but no changes in kick start.
So i thinked that maybe also the piston and piston rings should be too much worn, and i changed both piston and rings with Honda replacement parts.
But i still have the problems with kick start, i need to kick a lot of times to have a start.

I really don't know what i have to do, when i replaced the valves i did a grind by hand rotating the new valves in the old seats with a light grinding paste, maybe this is not enought to ensure a good sail?

Regards for your help from Italy

[Dirtdiver73]

Most common cause is a clogged pilot jet. Also, inspect the hot start nut. No start is either lack of fuel, spark or air. The attached link will help you with the pilot jet.



http://crfsonly.com/howto/450x/jetting/ ... needle.php

[crfsonly]

you do need to make sure you have perfect valve seal. if not, you will leak compression making it difficult or impossible to start. so, you need to verify you have valve seal. the seats should be cut by a professional with CNC valve seat cutting equipment.

if the bike was sitting for awhile with fuel in the carb the jets will likely be clogged and need to be replaced.

ken

[mira_mx]

Hi,
today i have cleaned every part of the Carb with compressed air, it wasn't really dirty and the jets don't seems clogged but after that the bike starts agane with few kicks, so the problem was in the carb.
Really thank you to help me!!!

Regards from Italy!!

[crfsonly]

glad to hear this helped and your bike is running again.

ken

[mira_mx]

Hi guys,
yesterday was my first day at cirquit, it seem to work agane, but still don't work as before: now it start after a lot of kicks, specially when the engine is hot, it is really hard to start, i have talk with a friend that work in a Honda shop: he told me that he also got on a 250r as mine the pro-x valves and he has the same problems, the bike had lot of problems to start and at the 5th run one of the valves failed.
I'm really desperate, what do you advise? change agane the intake valves with oem? Have you ever heard about this kind of problems with pro-x valves?

Regards

[crfsonly]

are the valves clearances in spec?

[mira_mx]

I'll check agane the valve clarance, do you advise me different clarance for ss valves?

[crfsonly]

clearance is the same regardless of which valves are used.

ken

[gmgearhead]

may sound too simple of an answer but how about a new spark plug?