Steve St.Laurent

Mi. Trail Riders
Member
Feb 6, 2006
255
0
I've done a top end on my 89 CR250 and am trying to reassemble the hpp system and am having a nightmare of a time getting it together. I've looked at Eric Gorr's instructions (which seem to be missing quite a few steps) and the instructions in my clymer manual (in the cleaning section, reassembly section, and adjustment section). None of those seem to be helping. I have the cylinder on, the rack is installed and is definately engaged on the cam, I have the detent on the cam engaged. According to Eric Gorr's instructions the pinion shafts should drop in where the screwdriver slots are pointing at 1 oclock on the left and 11 oclock on the right (and that if they are pointing at 12 oclock they are timed wrong). The is a lot of play in the shafts (about 30 degrees - which is from the interface between the rack and the cam and it doesn't look worn). If I install the pinion shafts without the levers installed (so there is nothing to stop them other than the case) the only position they'll drop in is with them at roughly 12 oclock (if they are turned all the way that direction with the play taken out).

Here is a picture of the left pinion shaft with the play taken out clockwise:
DSCF0542.JPG


and here is a picture of the same shaft with the play taken out counter clockwise:

DSCF0543.JPG
 

Steve St.Laurent

Mi. Trail Riders
Member
Feb 6, 2006
255
0
If I take the play all the way out counter clockwise and put the pinion shaft where the screwdriver slot would point at one oclock which has the pinion shaft all the way against the case (where there's no way it could ever drop into the lever) it almost starts to drop in - you can tell that the teeth are almost meshing.

DSCF0544.JPG


Now these pictures are on the right side with the levers and such installed. The clymer directions say to rotate the adjusters clockwise on the right side (counter on the left) to
close the valve completely (Eric Gorr's instruction say nothing at all about the adjusters). If I turn the adjusters the direction the instructions say they pull the valves open - not closed. Here is a couple pictures with the adjusters turned all the way clockwise on the right side as they say (the two pictures are with the play taken out one way and the other):

DSCF0547.JPG

DSCF0548.JPG
 

Steve St.Laurent

Mi. Trail Riders
Member
Feb 6, 2006
255
0
As you can see the valves aren't even close to being closed. Now if I turn the adjusters the opposite way they say I can get the valves to close if I take the play out one direction but with the play they still open. Here is a couple pics of the right side with the adjuster turned all the way counter clockwise:

DSCF0549.JPG

DSCF0550.JPG


I would think that they should be held closed with them adjusted properly (the manual is pretty vague). Any help would be GREATLY appreciated - I'm going nuts! Keep in mind that the bike ran great before I tore it down - no indication of any problem with the power valve, just very low compression (100 psi).
 

Steve St.Laurent

Mi. Trail Riders
Member
Feb 6, 2006
255
0
Well, just for kicks I bolted it back together as it is in that last picture (turning the adjusters the opposite direction that the manual said) and left the left side cover off and started it up. At idle the valve close all the way (and bounces just a little) and it starts to open just off idle and will open all the way with greater throttle. I put the cover on and took it for a ride around the yard and it runs like a raped ape. It'll pull the front tire in the air with a cracked throttle in 1st. I'm thinking at this point that I'm just dealing with worn parts which is causing the 30 degrees of play in the pinion shafts (it is 17 years old after all) and that the manual was wrong in which direction I should turn the adjusters. Thoughts?
 
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