Tri -Z top end removal Pics.

[this old rz]

Okay, removed the cylinder & head today...it was full of coolant here's what I see, take a look and let me know what you all think. I'd like to just re gasket it, maybe a hone if necessary and put it back together and see if I can get her running.
1.) It has a Hot Rods (rod in it) maybke the crank?
2.) Head has pitting...but it "looks" old, not recent.
3.) Cylinder doesn't not appear to be scratched to "my untrained" eye, my nails don't feel any of the few marks that look like scratches, I still see crosshatch marks.
4.) What size piston do I have? The Piston reads 3145H and 515M069.50
Is that 69.50 and what is the max overbore on the Tri Z?
5.) Cylinder appears..bone stock unported to me, can anyone confirm that?
Thanks in advance
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[3 Wheel Drive]

You got 1 more bore left, there’s 70mm pistons for the Tri Z. The cylinder looks to be stock, not ported. Get a new top end gasket kit and get on with it!

Muthy has some new exhaust gaskets, you should replace that one too. 70mm is your last bore. Since the top is off take it to a machinist and have him measure the bore. You may want to get new rings and hone the cylinder if it’s within spec.

[ironchop]

That head looks pretty bad around the squish band area. Those dings and those raised areas get hot and cause more detonation. Looks like that topend had some piston rings for lunch. I believe there are quite a few shops that could recut that head to remove those dings.

I would rehone that cylinder too before reinstall. Actually I would measure the whole bore for wear first and then go from there but it's because I can't stand when I try shortcuts and I fail so I go OCD from the start. Plus you only have to take it apart once

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[this old rz]

Had the bore checked out it's okay, so I'm going to rehone and put it back together, I don't think I'll put rings in? Ordered a top end Cometic gasket set.

This bike has a DG pipe in it, can I use a factory donut gasket or does it require a special exhaust gasket there...I thought I remembered a post on this here not too long ago?

I suppose I should check the ring gap, and possibly the rod play...if it can be done with the motor in place? I haven't read up on this yet, If anyone has advice on what those two specs are. (Hot Rods rod and a Weisco Piston) orsuggestions..feel free to let me know...thanks.

All I want to do at this point is get it running. If I keep it It will go to Klemm or Scott Clough for either a Big bore or port job.

[ironchop]

Had the bore checked out it's okay, so I'm going to rehone and put it back together, I don't think I'll put rings in? Ordered a top end Cometic gasket set.

This bike has a DG pipe in it, can I use a factory donut gasket or does it require a special exhaust gasket there...I thought I remembered a post on this here not too long ago?

I suppose I should check the ring gap, and possibly the rod play...if it can be done with the motor in place? I haven't read up on this yet, If anyone has advice on what those two specs are. (Hot Rods rod and a Weisco Piston) orsuggestions..feel free to let me know...thanks.

All I want to do at this point is get it running. If I keep it It will go to Klemm or Scott Clough for either a Big bore or port job.

You definitely need to check ring end gap and I would get new rings no matter how good they look. It's $25 more out of pocket. If that's not feasible, at least check the ring gap so you know if the rings are too worn out. If they are too thin and brittle and decide to explode or hang on a port edge five minutes after you get it back together and fired up, you're probably going to have a bad day. That's what happened to your head to begin with. That's what it looks like when old rings let go.

Ring end gap is dependent on the ring manufacturers suggested specs. I'll bet if the rod isn't OEM then neither is the piston or rings so factory Yamaha specs may not apply.

Edit: just saw you said wiseco piston so their website probably has that info

Rod play....well I see no difference in checking it with motor out on a bench or still in a frame.



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[El Camexican]

You have a discontinued 33 year old vehicle in your possession. Do yourself a favor and rebuild it properly now that you have it apart.

Have someone who knows how to check a connecting rod look at it, hone the cylinder, replace and gap the rings and either smooth out the squish band, or spend $50 bucks for a good head.

When you get it put back together have it checked for leaks before you attempt to start it, or better yet have the seals and crank bearings replaced now.

Depending on which version of a DG pipe you have you may require a collar that fits over the snout of the cylinder that the pipe fits over. If you don’t have one, you can buy one on the site store. There should also be a crush style gasket that fits between the pipe and that snout. You can find them on eBay, and once you know what they look like you can find them in automotive parts stores.

If you want to take this a step further, I highly recommend that you have the base of your cylinder lapped to your cases and your cylinder head lapped to the upper surface of the cylinder before you bother to do any assembly. This will ensure that you don’t have any air, or coolant leaks in the areas that these engines are known for having problems in.

[this old rz]

More drama with the Tri -Z mismatched head stud nuts' (can't be good)��Check out the murdered case stud threads. �� No wonder this thing leaked like a faucet, (He had no way to tourqe the head bolts)��
Oh well , ya get what take paid for. U guess.
Really bummed out as there is no way I will make this ride with my friends now. Too bad as apparently there is a 3-wheeler group Club /Gathering/ Convention there this weekend.
I'm thinking of just buying another bike quad or anything and then sell it the next week unfortunately with my luck the damn thing will blow up and then I will be out that too ��. My friends very rarely all get together and go riding this is the first time in 6 years251810.251811

[ironchop]

Damn. What a mess.

It's disappointing that you'll miss the ride but it would've sucked infinitely more if you'd have went and it grenaded halfway up a dune an hour after arriving

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[yaegerb]

It’s not the end of the world. Partzilla still sells oem case studs and dowel pins. Those are fairly easy to remove with heat and a stud socket set.