Am planning to take my 750 apart this summer to see if everything is ok and to see if the crank is welded. I keep seeing base gaskets available in tickness .010, .018, .020, .031, .039, .047 and .059 thousandths. My question is can any body be technical with this. I know it brings the cylinder up so it should change you timing but how much torque or hp you get? what do you get from what tickness? etc.
base gasket ???
- Thread starter marc8_2
- Start date
When you do the cylinder lift, you also have to shave the heads to get the compression back to where it needs to be. You can go any combination of numbers that you want, but a .39 cylinder base gasket lift is pretty common. Then, you can shave your heads any amount you want to set your compression to where you want it depending on whether you want to be able to run pump gas, or only high octane. HP gains depend on the amount of compression you want to run obviously. It also matters whether you have 89A cylinders or 8AX cylinders. There was a difference in the ports between 92, and the 93-94 750 motors. If you have any of this done, it is best to have someone who knows these motors do the work!
In my opinion, not enough gains to justify the cost. Especially on a 92 motor with 89A cylinders brought back to stock compression. In my opinion, best bang for the buck is to install 800 pipes, or another set of aftermarket twins or quads, then blueprint your driveline and run a good clutch set-up. Yamiegods set-ups that are listed here on the sight work very well. I would make sure that the crank is welded just for reliability. If you do all these things, your performance will be increased greatly, without spending a lot of money on motor work alone. Just my opinion.
Vmaxmike
Member
First thing to do is check ur squish before you take your motor apart, to see where you are at. It's possible to regain some of the lost compression by using a single layer head gasket, instead of the three layer that was original to that year. I chose to use a .039 base and take .020 off the heads, this alowed me to run pump gas with a two layer gasket or use a single layer and use 50/50 (pump,race)
My attitude is your already that far into the motor, why not. Just call and find out the cost to shave ur heads and decide if you want to spend the money.
M
My attitude is your already that far into the motor, why not. Just call and find out the cost to shave ur heads and decide if you want to spend the money.
M
Vmaxmike
Member
The quads are a bit loud for our trails around here, but I have a BIG grin everytime a squeeze the trigger.... LOL
My build turned out great, don't have much time on it yet due to lack of snow around here.
My build turned out great, don't have much time on it yet due to lack of snow around here.
Vmaxmike
Member
Indexed & welded cranks, double base gasket, .020 shaved off heads, .50" piston window, OEM rings, seals & Gaskets, 8BU CDI, 800 jack shaft and secondary, extrovert drivers, Aaen High RPM quad pipes, digatron gauges, Hydraulic brake, Tony's help with clutching, and a different rear skid and skis.
so basicly a stock '92... LOL
M
so basicly a stock '92... LOL
M
Ken
Moderator
In my opinion the 92's benefit the most from raising the cylinders as they have the mildest port timing. The 92 is also the only year that doesn't have windows in the pistons, so you can also get some gains by updating to the 93/94 piston or adding windows to your 92 pisttons. Depending on how much of a lift you do you can probably get about 6-8 hp across the power band.
Ken
Ken
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Vmaxmike
Member
Talk with Ken about the hole size and location, he did a great write up on this subject. The thread is here somewhere, look it up I used his info when I did mine.
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