300ex head

[croom9]

Can you put a 250x head on a 300ex jug, or are they different in ANY way?
Any comments are appreciated

[Tyler01]

No same fit and every thing except the jug is smaller on the 250x but still fits up perfect

300ex and 250x is pretty much the same 4 wheeler except motor (as in jug wise) body and 250x dont have a stator

[croom9]

ok im gonna take your word for it and give it a whirl, i found a used head for 125 bucks from a 250x, the guy says it wont fit, and the honda dealer says the part numbers dont match, but i looked up both fische's saved them and opened them both up next to eachother and i cant spot one difference so ill try it. and your sure that the timing is the same (cam specs, cam gear)?

[Tyler01]

Yea they are pretty much the same the difference is that

300ex-bigger piston,Electric start

250x-smaller piston,kick start

and just other lil stuff

but every thing should fit all together but if u wont one more advice ask
Tommy Warren http://www.exriders.com/vbb/showthread.php?s=&threadid=409113 Go down until u find him and send him a private message and he should know to

[born2ride14]

Dude you might wanna check what your saying before you say it, because the250x has a shorter stroke not a smaller piston

[Tyler01]

O im so sorry i totally forgot about that.

[croom9]

Originally posted by croom9
Can you put a 250x head on a 300ex jug, or are they different in ANY way?
Any comments are appreciated
well i finally got around to taking my 300 apart and found out what exactly was making all the racket the balls in the cam bearings look like little planets (saturn with its rings around it lol) and its loose as hell. but the races look good so i dont think it spin in the journal, down side is that the rocker faces are hammered lol, do you think I can get away with using the same head, and an a different calve cover with rockers in it or do you think it will pinch the bearings if the tollerances are even the slightest bit different (if it did spin)
heres a crappy cell phone vid but you can hear the loose cam <object width="445" height="364"><param name="movie" value="http://www.youtube.com/v/0jlNnd3JaaI&hl=en_US&fs=1&rel=0&border=1&autoplay=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/0jlNnd3JaaI&hl=en_US&fs=1&rel=0&border=1&autoplay=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="445" height="364"></embed></object>

[smr]

Originally posted by born2ride14
Dude you might wanna check what your saying before you say it, because the250x has a shorter stroke not a smaller piston

You are 100% correct. The jugs are the same, the only difference is the crank. 300ex has a longer stroke.

Now as for the head. They will interchange but....You will need to do something with the decompresion lever. I usually pull them out and insert a plug with JB weld. You can also tie it in place.

good luck.

[croom9]

Originally posted by smr
You are 100% correct. The jugs are the same, the only difference is the crank. 300ex has a longer stroke.

Now as for the head. They will interchange but....You will need to do something with the decompresion lever. I usually pull them out and insert a plug with JB weld. You can also tie it in place.

good luck.
Thanks for the clarity
One question on your reply though.
I hear that when you install a hotcam, it is hell on the starter, would it benefit me to leave the decompression lever on and use use it when i start it? IF i were to put a hotcam in it ?

[cheatermtrsprts]

I have a brand new in the box never installed hot cam for $100 if you are interested.

[smr]

Originally posted by croom9
Thanks for the clarity
One question on your reply though.
I hear that when you install a hotcam, it is hell on the starter, would it benefit me to leave the decompression lever on and use use it when i start it? IF i were to put a hotcam in it ?

Not how you would make it work.

The decompression lever works off the kick starter and cracks the valve open for just a monent to start the stroke.

[croom9]

Originally posted by smr
Not how you would make it work.

The decompression lever works off the kick starter and cracks the valve open for just a monent to start the stroke.

Oh ive never seen a 250x that close... never had one, I expected the decomp lever to be something where you manually lift the lever up each time you kick it......

Maybe i could make it that way... if i find out what connects it to the kick starter
i found a fiche of 300 ex and 250x heads the 250x seems to use a cable for decomp, use it manually at the handle bars?

[dman66]

Hi,I have an 87 250x, The lever on the head connects to a lever behind the kicker. Inside the engine is a cam follower attatched to lever on outside of engine-behind kicker. The lever on head cable connects to lever behind kicker. When you kick start, the rear lever pulls cable backwards in return pulling the head lever towards back of head or down to the valve inside head. I have an 75mm wiesco piston in my quad, and kicking engine over is easy as long as you set timing correctly. My 10 year old daughter can almost kick startthe engine and she has never been on a quad before.

[croom9]

so in theory i could put the 250x head on my 300ex jug and route the cable for the decomp to the handle bars w/ a lever instead of the kicker since the 300ex doesnt have kickstart? and use it that way?

[dman66]

I would imagine you could do that, as long asyou can set and adjust the decomp lever on the head properly.