Log in

View Full Version : GPX 250 Cam chain



Gixxer 4 ever
9th December 2005, 13:34
Hi ppl. We are about to do the cam chain on my son's 1988 GPX 250. Manual on the way. Anything we need to know that is out of the ordinary or will make the job quicker and stop us doing something that makes work later?
Also should we us an endless chain or just pull a new chain in and us a joiner? Then retime etc?
Thanks

FROSTY
9th December 2005, 13:42
Open petrol cap ---pull grenade out of pocket -remove pin -insert granade in petrol tank--step briskly away from bike
Ok thats the dissasembily taken care of......:2thumbsup
Tensioner can be a sod it seems to take 3 hands to retract it
I'd do the split link thing to be sure.
Otherwise as i recall pretty straightforward.
Dumb question--are ya sure the chain is Knackered -Have ya tried giving the tensioner a little"nudge" to be sure its fully extended
If its any help the GPX and GPX motors are basicly the same

Gixxer 4 ever
9th December 2005, 14:00
Open petrol cap ---pull grenade out of pocket -remove pin -insert granade in petrol tank--step briskly away from bike
Ok thats the dissasembily taken care of......:2thumbsup
Tensioner can be a sod it seems to take 3 hands to retract it
I'd do the split link thing to be sure.
Otherwise as i recall pretty straightforward.
Dumb question--are ya sure the chain is Knackered -Have ya tried giving the tensioner a little"nudge" to be sure its fully extended
If its any help the GPX and GPX motors are basicly the same

Hi Frosty
Thanks for the reply. If you dropped anything other than petrol in to a GPX fuel tank it would fall apart.:slap: All the early ones have rust.:angry:

Yep we took that out last night and had a good play with it. I lengthen the ones on the Yamaha AG 200. I add about 10mm and they last for ever but the boy is not wanting to do that and would rather replace. He is not wanting the chain to peal the alloy off the cast should it touch it and stuff everything else.
I assume you mean the GPX and the GPZ motor....? Thanks for the help. See you in Taupo.

Gixxer 4 ever
9th December 2005, 14:08
The tensioner is easy to work with. You undo the grub screw in the top of them when they are out. Put the long spring in the top. compress the long spring and the steel insert. Screw the grub screw back in and it holds the tensioner. Replace the unit in to the motor and then undo the grub screw. It lets the Tensioner go. Then screw the grub screw back in to stop oil leak. Very clever really.

speights_bud
15th December 2005, 21:01
:done:
Well was working with dad (G4E) on the GPX tonight and have sucessfully finished the job. we had no worries all up and the 'riveting' of the new chain went well. The new chain has turned it into a brand new machine. It used to make tapping and knocking sounds that could be heard even with the helmet on at 50k's through town:pinch: but now its smooth runnings.

Was a bit worried after assembly had been finished because she just wouldn't fire. after nearly killing the battery through repetative cranking it was decided to push it down the bloody great hill we live on, which shortly after beginning it fired into life:woohoo:.

Cheers for the advice guys and hope to see some of you at taupo:niceone:

Now to go ahem 'wear out' the old tire so i can slap the new rubber on:devil2: ...

sefer
16th December 2005, 20:18
Just out of intrest as someone who intends on doing the chain in his zxr250 this week (I keep forgetting to order the thing though:doh: ), how easy was the riviting? Did you already have the correct tool or did you have to go buy it?

(I sense that the riviting will be the big issue for me, not having the tool to do it with.)

speights_bud
16th December 2005, 20:43
well we just used a really big bolt head that weighed about a kilo and a punch with steel hammer to spread/rivet the chain link. didn't have the proper tool...

Gixxer 4 ever
17th December 2005, 09:17
Two pair of hands work well. My Son held a heavy 25mm bolt head against the back of the chain links and I hit the pin with a centre punch. The hit was firm with a steel hammer. Not hard with two people. The side plate fits very snugly onto the pins of the joining chain. I use an over sized socket that is big enough for the pins to go inside but small enough not to hit the chain links next to the one you are putting on. If that makes any sense. Make sure the link plate goes on evenly. Because if it goes on to one side more than the other it can be hard to even them up. While I fitted this plate my son held the back of the link with the said 25mm bolt head so I could tap it on.

The hard part is to have all the other gear. Like a compressor and a rattle gun to get the clutch cage off and a good socket set and Allan key set. A manual is essential unless you know about timing marks and the correct replacement of cam caps etc. With the info and the gear it is easy. Make sure you have no pressure to get the job done. Like a track day in Taupo.....:wacko: ....My sons first track day and his bike was in bits in the shed waiting for parts. Life was stressed.... Good luck. Take your time and read plenty. For us it was a good learning lesson but with the gear we have it was easy. One more tip. Never tighten the cam caps if there is any pressure on the cam lobes. Things will break.

Have fun.