xz550 piston

[fiatracer]

Does anyone in the WORLD make a replacement piston for the xz? my 83 developed a knock so i am rebuilding a spare motor. Help!

[fret not]

And what leads you to the conclusion it is the piston that is knocking?  More likely the starter clutch or balancer shaft gear.  If the oil light comes on when the motor is running it may be a rod bearing.  How many miles on this motor?

New pistons are just about unobtanium these days.  Not long ago I was checking for rings and had no luck so far.  Of course there is the serious racer's way, and that is to get some custom made, but of course you would have to get the crank re-balanced for the new pistons most likely.  This is an expensive way to go.

The most likely resolution is to use parts from a low mileage motor, which is why I think it a good idea to have a parts bike. 

[fiatracer]

i have a parts bike but was tryin to save it for another build. mine has 33xxx on it. at an idle it sounds good but as you rev it it starts an annoying knockin sound. but no oil light and seems to have good power and no stumble or hesitation. how do you diagnose other issues?   i have never had a V with lower end problems? Jon

[Rick G]

Sounds like a loose balance shaft nut. Hows the starter clutch ?  many times  these have been mistaken for a bad rod bearing.

[fiatracer]

i went all thru the starter clutch! i will chech the nut next. I was told by a friend that the cluch basket can make the same noise. true?

[Rick G]

The Vision has straight cut primary gears , which can be a little noisy , but you won't mistake that noise for a bad rod .
The balance shaft nut has fooled many wrench's, who were not familiar with the XZ.

[fiatracer]

i think we can rule out easy fixes! while probing with the stethascope the motor locked up! thoughts? i am back to the bearings i think

[fret not]

Probing for noises and it locked up, and the oil light didn't come on?  Maybe the nut came clear off the balancer shaft.  Only way I know to find out is to remove the side cover and get a good look, and hope you find the answer there.

[fiatracer]

i will look in the am. no oil light at all. stumped!

[Hartless]

Probing for noises and it locked up, and the oil light didn't come on?  Maybe the nut came clear off the balancer shaft.  Only way I know to find out is to remove the side cover and get a good look, and hope you find the answer there.

Probably a faulty oil sensor. I heard his bike and it sounded exactly like the two engines I just got done tearing apart that both had bad rod bearings. Though I only heard it over the phone.... I hope it's something simple John!

[fiatracer]

i will let you know tonight! diggin into her. i might have to rebuild the streetfighter motor early and put it in my black bike!

[Rick G]

I've lunched two rod bearings, both while riding . It starts with a bit of tapping and a decrease in power. The noise rapidly gets worse and power drops off severely. A very short distance farther the engine is barely able to run and the  engine finally  quit.   I had ridden it 18 miles to the top of Coyote pass, so I could coast in to Kingman and avoid high towing bill.  The second was similar , except it happend on a down hill on I 40, as I was going to work. I managed to ride it to the shop and shut it off. Trucked it home and put a used bottom end in.

[Blake]

Does anyone in the WORLD make a replacement piston for the xz? my 83 developed a knock so i am rebuilding a spare motor. Help!

The places I called were all willing to make them, but usually had a minimum order of 8 or 10. 

[fiatracer]

and prolly really expensive per unit huh?

[Rick G]

I have a few very serviceable used pistons. Rings are a problem. I checked into using car rings in 2003. There is a set of Toyota rings that would work for the top ring and Honda rings that would work for the bottom and oil rings. . It would involve buying two sets of 4 cylinder rings and getting enough for 2  Visions. Cost in '03 was around $90.00 a set. I posted this info. on the forum at that time.
Since then, TNT auto parts machine shop told me about a company in LA, who would custom make 1 or 2 sets of rings.
If I can help let me know.

[motoracer8]

 JT will make you anything you want, 4 are minimum they are willing to make. About $200 each, that includes rings, better than the Yamaha rings. I've used them in many of my projects, never an issue.

For just rings you might try Total Seal. You will have to know what you want, width, depth, diameter etc. They have 100s of sizes.

  Ken G