TTR125 Head Gasket

I have a TTR 125 with a 66mm piston from a 70's XS 360 in it ( A friends Frankenstein project) I was wondering if anyone knew the thickness of the stock head gasket? I need a new one and want to maybe go thinner and boost the comp ratio a little. And oh yeah it runs VERY good!!!

Sorry I don't know the exact answer to your question. I did find this little tidbit though: -High-compression kits use.012" thick base gaskets to raise compression.

Thanks, That is more info than I have been able to find. Jerry

Holy crap that's a big piston for a TTR!! How thin is your cylinder wall? What does your head look like? WE DEMAND PICS!

Lani from Copper gaskets u.s. can make you whatever you need

I will getsome when I pull the head. It is kinda interesting when the stock sleeve has ~ 1/4" clearance in the hole for the piston! And like I said I haven't finished jetting it, that will have to wait til after the head gasket. But right now oil leak and bad jetting and all it is a monster 3rd gear wheelies very cool!!

I dont know but I know a ybr 125 head gasket fits perfectly on a ttr 125 engine

I did some poking around, and most stock head gaskets I have are .030 thick. Using too thin of a head gasket may cause clearance issues. Clay and check

I will getsome when I pull the head. It is kinda interesting when the stock sleeve has ~ 1/4" clearance in the hole for the piston! And like I said I haven't finished jetting it, that will have to wait til after the head gasket. But right now oil leak and bad jetting and all it is a monster 3rd gear wheelies very cool!!

The way I'm reading this, the piston is 1/4 of an inch down in the hole?

I'm sketching out a 190-200cc Yamaha 4 stroke for one of my Yamaha-lifer friends, and if I can see what your combo is and get a review on how it performs, I might duplicate it. Otherwise, I've got a XT200 bottom end kicking around in my dad's shop that needs a crank job (as I found out recently) and a plan:busted:

ok so you have the 175cc Big Bore Kit ? An .030 gasket is the recommended thickness

Piston is not down in the hole a 1/4" it has @ a 1/4" difference in diameter from stock. An yes it is waaayyy big. And yes you can see the cylinder sleeve from the outside. But Yes it hauls A-S I will run it til it breaks or I need a rebuild. I am racing it in a maddog class on the local 1/4 mi. Flattrack. gotta love third gear wheelies. I am using a 16 thousand head gasket, I have two base gaskets under it for deck height, and I machined the outside edge of the piston to clear the combustion chamber on top. It is @ a 12:1 CR. Issues I have are on these the oil to the head goes up and down the right side stud holes and I have some leakage there due to the sleeve being a little proud in this area. I am going to tear it down and have the cylinder machined flat and also machine grooves in the oil passage area and install o-rings in it to correct the issues. Jerry #57G http://www.thumpertalk.com/forum/images/smilies/cool.gif

That's insane... I'll go with my XT route. Less work lol.

I'd love to be able to think up something like that and make it work. Instead I duplicate others combos when I can, or create ones that are simple when I can't.

Maybe a BBR 150 cylinder would be better suited for your big bore? I can't see how your sleeve wouldn't intrude into your cam chain tunnel.

Still... that is a bitchin combo.

Issues I have are on these the oil to the head goes up and down the right side stud holes and I have some leakage there due to the sleeve being a little proud in this area.

Can i get a bit more info on the way the oil travels up to the valve train? Are you saying the oil uses the head bolts to go up?

Can i get a bit more info on the way the oil travels up to the valve train? Are you saying the oil uses the head bolts to go up?
The head bolt towards the exhaust port (forward corner on the clutch side) is the oiling path. It comes out of the pump and runs into a port on the clutch side case half that sets back a bit from the bolt, but the gasket/cylinder diverts it to the bolt hole and up the cylinder to the head. Then it just uses the motion of the cam/rockers to oil the head and makes its way back down into the case using gravity through the cam chain opening.

-Kerry

What he said, although usually the manufacturer put either one of the locator pins or an o-ring in the passage. I believe I will put in an o-ring. The sleeve doesn't intrude into the cam chain area but it is darn close. I have a 28mm carb on it which makes it run very good. I will eventually put an aftermarket pipe on it, but for now the stock one will do. I cut the muffler apart and gutted it and then welded it back together. I put supertrapp discs on it and machined an aluminum silencer tip for it. The pipe seems to work okay. Jerry http://www.thumpertalk.com/forum/images/smilies/bonk.gif

I heard dat most normal ttr 125 gaskets are 10 mm wide and if you boost up the ratio comp up it actually can put the motor off beat!

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