Some 3Z Questions

[Six Stroke]

I picked up a basketcase Tri-Z the other day in dire need of TLC. Since my experience is mostly limited to the 2-stroke Tri-Motos, I have a few questions:

Are there any other bolt-in Yamaha 250 engines? What I'm asking is this: Will a certain year of YZ250 engine drop in and work with the reverse kicker?

If no, then are the YZ and Tri-Z cases the same?

I saw a link on here several years ago for the powervalve cylinder swap. Does anybody know of this link? It was a magazine article, or something. Also, is the powervalve swap even worth it? What are the pros/cons of doing such a mod?

I'm sure I'll have more questions, since this is shaping up to be a long, slow rebuild...

[Mosh]

83-86 YZ 250 engines will drop in.They are powervalved, but you will have some intake fitting issues since the bikes are larger reedblocks and slanted in the jug casting.
Also, you have to add a vacumm port in the YZ cylinder for the Z fuel pump.
You will also have to mess with the exhaust fitment due to the bike having a larger flange opening.

You can convert the YZ to front kicking by swaping the z sidecover and kicker gears to the YZ engine cases.
You will loose your lighting system since the bike flywheel and stator do not fit the Z Crank and vice versa..You can put a Z crank in the dirtbike cases and run the Z stator and lighting coil on the YZ engine.

Honestly, I dont see a direct benefit for the YZ engine other than it revs quicker and has large intake.So maybe a little more top end than a Z engine.
Most will argue a powervalve makes MORE power, but it doesnt really..It just moves the torque range around in the RPM range pound for pound in engine size.

I will find you that link..

http://www.3wheelerworldforums.com/showthread.php?30686-How-to-power-valve-your-Tri-Z&highlight=power%20valve

[Six Stroke]

Huh...the powervalve swap doesn't seem to be woth the trouble at this point. I'm glad I can swap the cases around, though. That'll make my life much easier to live. How about rod selection? Stock? Hot Rods? Something else?

[Six Stroke]

*crickets chirruping*

Anybody?

[Mosh]

Sorry I took so long to get back to you on the rod selection.

Personally, nothing beats stock, but I have used Hot Rods many times with no issues.
Lately, I hear their cranks have been having high failure problems. But then again, who knows?
It seams to be more of a bearing issue then the rod. So even one of their rodss with a different brand bearing may be an option.

So you can check Wiseco, Pro X and Crank Worx, out and see what they have to offer, for a Z rod.
Vesrah used to make rods, not sure anymore. But their clutch and brake components never impressed me, so I doubt I would use a rod from them.

[Six Stroke]

So stock should be just fine. Alright. Any suggestions on where to get swingarm bushings/bearings (or whatever it has)?

[Dirtcrasher]

Use stock for your crank whenever possible, they last the longest IMHO.

I'd contact one of the few guys on the board for an All Balls bearing kit for your axle, wheel and swingarm pivot/suspension bearings.

[luke]

"dads" on here does the swinger bearing kit's, they are also listed on feepay.

[Six Stroke]

How about some sort of case saver? I see quite a few cases with chain damage...

[3wheelmecca]

Make one with a mill. Or eBay.