[kaiserkaiser]

Hi there, i have a 2005 CRF450X that runs 1 qt of oil(Putoline GP80 ) .
Today i was riding and the bike when i increased the RPM's in 5th would change to 4th. If i ride 5th at low RPM's the bike runs normal, if i increase the RPM's she changes automatically to 4th. The other gears run fine with no problems.
Any ideas what of wath is the problem?
In the last weeks the 5th sometimes poped out to 4th when i was wheeling and started to do more often when i changed from 14-42 to 15-42 gearing (she have 17' supermoto wheels).
I know 2005 have this transmission problem, so i think i will need to split the cases, any more things i should be focused since i have the cases splitted?
My bike is burning a little oil too, any suggestions in terms of Pistons or just use the TRX one ?
Can i ride the bike like this? I would like to ride some more miles until change the piston, i did 2200 since September, i was thinking in do 3000 and then change piston. The bike tops at 88mph in forth so i can ride just with 4 gears with no problem.
Thank you for the help.

[JimDirt]

I am guessing you have a bent shift fork , this is usually the cause of it popping out of any gear , so yea , the cases have to be split , now would be a good time to check your valve clearance before you tear it down , since its going to be apart , if the valves have moved any , its best to do them while you have it apart , as far as piston goes , its all a matter of personal preference , you can get 10 people with 10 different answers as to what is "best" , i use JE pistons , but the TRX is fine as well , a Cosworth will last a long time , and give better performance , but are spendy , PM Ken , as he has probably installed every brand available and can guide you as to what would suit your needs the best

The 1 qt will help with cavitating the oil from the gear area , but will not do anything in preventing a bent fork , the only thing i can think of is either you jammed the shifter into something like a rock or during a fall , or forced it into gear under a load at some point (under a load , like while still on the throttle without using the clutch) , hope that helps some ...

[kaiserkaiser]

I am guessing you have a bent shift fork , this is usually the cause of it popping out of any gear , so yea , the cases have to be split , now would be a good time to check your valve clearance before you tear it down , since its going to be apart , if the valves have moved any , its best to do them while you have it apart , as far as piston goes , its all a matter of personal preference , you can get 10 people with 10 different answers as to what is "best" , i use JE pistons , but the TRX is fine as well , a Cosworth will last a long time , and give better performance , but are spendy , PM Ken , as he has probably installed every brand available and can guide you as to what would suit your needs the best

The 1 qt will help with cavitating the oil from the gear area , but will not do anything in preventing a bent fork , the only thing i can think of is either you jammed the shifter into something like a rock or during a fall , or forced it into gear under a load at some point (under a load , like while still on the throttle without using the clutch) , hope that helps some ...

Thank you for the help.
Last trackday i did i slided and crashed. The gear shifter bent to the front, that could helped. I do wheelies, i dont know if in any wheelie i forced too much while shifting, lately she pop out the 5th while doing wheelies, i lift it up in 3rd and when i changed to 5th the gear would pop out but running normally the bike was fine. I will open the engine soon and see what happened.
In terms of pistons the options i have are OEM , Wiseco and Vertex, i am in Europe and this is the ones i have better price.I will check the condition of the piston, if needed a new one i will go maybe for the TRX OEM, if still good i just change the rings, the bike is running fine and starting fine so i dont think the piston and valves are really bad.

[JimDirt]

Yea it sounds like that is most likely what caused it was the crash , as far as piston , the TRX is what i would choose of those options you have , , i just mentioned the valves since you will have the head off anyway , and once you have to shim them once , then they will keep needing adjustment , so IF you have had to adjust them , then now would be a good time to do them , and get it all done at once so you have a fresh engine when you get it back together , , its not mandatory , just a suggestion to avoid having to tear the top end down again ....

[kaiserkaiser]

Some news, i splitted the cases and found the problem. The shifter drum is missing a little of piece (at the side of the Y).

I will now order the parts and start rebuilding, i will get new 3rd and 5th just to be safe and because this 2005 are prone to get problems.
The Piston is good so i will just get new rings and a new cam chain.[/img]

[JimDirt]

Also , VERY CAREFULLY look over the shift fork , make sure its not also bent , also , search for all the shrapnel , you don't want any cast metal roaming around in the transmission , so make sure you clean every part thoroughly , including flushing out the bearings and spinning them while flushing to "feel" for a debris .... Good Luck !!

[Back2-2]

Looks like you found your problem. Try to find the missing piece. Hopefully it is still in one piece.

For what it's worth - The Vertex are top notch pistons. They are the manufacture for the pistons in the bikes from Japan.