Hi all,
As some of you know, I picked up a really cheap '88 Paso 750 to replace my long lost Paso that I (sigh) sold 15 years ago. Gone but never forgotten! This bike was cheap because it had a gaping hole in the case from the chain breaking.

So, in an effort not to let this damage happen to my new lower end, I pulled off the chain guard, and put a straightedge across the rear sprocket, and sure enough, it lands slightly inboard of the centerline of the front sprocket, maybe 3mm off. Now, ordnarily I wouldn't think anything of 3mm, but seeing what happened to the last owner, I think I'd better fix it.

I looked at disassembling the eccentric adjuster, to see if there's any room for adjustment, and got a broken 7mm allen for my efforts...

On any other bike, I'd just move the adjusters to compensate, but on this bike... The front sprocket is on correctly, the big boss is inside. turning it around is WAY off the other way. My only other thought is putting some washers behind the rear sprocket to bring it out an equal amount, or a 3mm ring between the front sprocket and the locking retainer ring.

Any thoughts?

And as a side note, maybe some people get lucky, and can fix a lower end with Devcon or RTV (that was my plan before I bought the bike, damage described but unseen), but you should see the hole mine had! I've got pix, if anyone wants to see!

Aw, c'mon, no ideas on aligning the chain? Don't let this happen again!



I put washers behind the rear wheel sprocket, but then, after talking to a friend who is knowledgeable on metals and machining, pulled them out and put two washers in between the locking tab and the front sprocket instead. It's pretty close, only about 1mm off now. I test rode it and it works, so far at least....

I'm also open to suggestions on how to disassemble the rear eccentric! I can get the big aluminum nut off on the left, but that steel bolt down inside, with the 7mm allen, that thing is IN there!

If the screw is not rusted in the aluminium thread (only too tighten) I would drill the head ,to remove it, and unscrew with strong good plies.But bigin by a 5mm drill, deep hole to be able to use a screw extractor if necessary. dont remember "magic" WD40!
Alain.

Dont FORGET (bad english) WD40. You could use an impact-driver. And heat the swing-arm.

Del,
I've not had my swing arm off before, but If I was faced with the 3mm offeset that you are having trouble with I would work at the pivot point of the swing arm. Typically, there are swingarm bushings located at the pivot point. I've been looking at both the parts manual and the service manual and this appears to be true. The part is marked in the parts manual as "distance piece" #12. Would it not be possible to have 3mm ground from one side and add a 3mm spacer to the other to take up gap? This would shift the entire swingarm over 3mm. You may also need to pay attention to the linkage at the same time and may need to do a similar thing. I don't think that I would attempt to cure this at the rear of the swingarm as you will want to be able to install the wheel in a normal fashion and not worry about alignment each time a tire is changed.

Also I am curious can you detect any damage anywhere on the swingarm or frame? Possibly the reason you are having this problem is the frame or swingarm is bent. Has the bike been down hard to your knowledge?

Doug

Ok, the swingarm spacers do sound like a good place to start. I suppose I should try Dr Rob Tuluie's "chassis alignment" and see if the swingarm is misaligned as well. If so, changing the spacers could fix both... Here's the link to his page:

http://www.motorcycle.com/mo/mcnuts/chassis.html

No, I don't see anything obviously bent on the swingarm, but this bike was reassembled with 907 bodywork and tank, so something must have led to that (like a big crash?).

As far as that bolt, lets see: PB Blaster, torch, bees wax, torch, butterfly impact, a real impact, a 2' long breaker bar, and then SNAP! (repeat this method 3 times, now have 3 broken 7mm impact sockets-oh wait, the service manual says to repeat this method 4 times!)

If all else is OK then I'd shim the sprocket over 3MM. If it will go over that far that is.

The part number for the sprocket is correct?

Broken bolts are a bitch. where are you heating them? IF you heat the bolt it get tighter in the hole, so I hope your trying to hear the swingarm.