1982 KZ750 shaft

I have purchased a KZ750 for 200 dollars. All four pistons were seized. I have freed 3 of them and the last if giving me trouble.
I have the carburetors completely cleaned but all four slides are seized. I have used vinegar, liquid wrench, paint thinner, boiling them in lemon water, carb cleaner and wd40. Nothing has worked. I have done the same for the piston too. I really need help with this cuz I’m not sure what to do next. I hope to make the bike look like a cafe racer or brat.
 
Any help would be appreciated.


Also, is there a better thread for this kinda post?

Use heat on the outside of the carb body. A torch flame or heat gun will work. Heat will soften the varnish holding the slides and allow you to push them up and out.

In order to properly clean the carbs you need to ungang them, remove all jets and pilot screws, and soak all the hard parts in carb cleaner. Then reassemble with new O-rings. If you are planning to use pods spend the money and get some proper K&N's and a Dynojet kit. The bike won't run for crap, if it runs at all, with the stock jetting and pods.

Good luck

Yeah, I have thought about that but someone told me that I shouldn’t heat Aluminium. I guess I can try on the carbs but what about the piston? I let pb blaster sit for 19 or so Hours, no luck. Now I marvel mystery oil on it. Can I use the torch on the cylinder? Or is it bad to heat the cylinder. I’m not sure if it’s aluminum though. I think it probably is.

MMO is good. I'd let it sit for a few days. Heating the piston top won't hurt. If you have visible red rust in the cylinder you may be screwed and need a new cylinder or to bore oversize.

BTW, I freed up the slides using heat on some 750 carbs just last week.

No eBay APP ID and/or Cert ID defined in Kunena configurationAlso I need to replace the Pistons. I don’t want to spend 400$ on wisco Pistons. But what about these, are they good/worth the money?



Wow! Sorry that was long.

No eBay APP ID and/or Cert ID defined in Kunena configurationThere is a member here that used those pistons recently. Maybe he'll chime in with a review? Overall the reviews for cruzin image pistons is decent. There is a place out of England that sells overbore pistons for the 750, you can find them on ebay. The advantage of this other set is that the overbore is less so the liners are thicker which I think is good. I'm pretty sure those English pistons are not pistons made in England though. I suspect they are made in China to the English companies specs. It's hard to know what's what these days so good luck with figuring it all out.

Edit: here is that other set mentioned earlier...

But the ones you sent me are still crazy expensive. I guess that’s how it is. So don’t go with the less expensive ones I sent you? Also I need to buy a new head. I think. The valves are super rusted and I don’t know if it’s worth saving. Those carbs are still giving me trouble. I got a torch yesterday. I just need to take off the carbs one by one and heat the wall up. Hopefully that works.

Great care should be taken with a torch. Aluminum melts at just over 1,200 F. A common propane torch can produce 3,600F. I'm certain these parts are alloys, not pure aluminum but it doesn't change the point. Producing 3X the melting point heat should not be taken lightly. It certainly can be done, but you can't just hold the flame on it indefinitely.

I would soak it with Kroil for 3 days reapplying Kroil each day. Ed

I removed some stuck slides just the other day. Heat is the stuff. A torch on the outside of the carb body, both sides, for about 15 seconds is all that's needed. You won't hurt the aluminum in the least. I've done this on several sets and never one time had any issues with damaging anything.

JohnLuke wrote: But the ones you sent me are still crazy expensive. I guess that’s how it is. So don’t go with the less expensive ones I sent you? Also I need to buy a new head. I think. The valves are super rusted and I don’t know if it’s worth saving. Those carbs are still giving me trouble. I got a torch yesterday. I just need to take off the carbs one by one and heat the wall up. Hopefully that works.

Like I said, there is a guy here that used those cruzin image pistons. Here is his thread... PM him for info... www.kzrider.com/forum/11-projects/602462-kz750e-resto-mod