Suzuki 2 Strokes

Hello! all! i was reading in my old clymer manual with the "performance how to" chapter, and it said you can mill 1mm off of the head to raise the compression ratio. has anybody done this? my head is off of a 1977 gt 750 B which if i remember has higher compression than previous years? if i milled 1mm off would reliability become an issue? My buffalo is .50 over and has a 3 into 1. in the book they say up to 3mm can be taken off but that seems like alot.

any advice would be great! thank you!

I'm so far from an expert its ridiculous - BUT- I think you would get a larger gain with one of those riser blocks between the crankcase and cylinder block. Changes the port timing.
I don't think added compression helps these old 2 strokes much, but you don't have to worry about bending a valve.

Do you know of anyone who has done either? would your compression go down with a riser block? or would it stay the same? how would it affect the power?

When you use a lift plate, you have to mill the top of the cylinder the same amount. I have a lift plate in my 750, a milled head, and 1.5mm off the rear skirt of the pistons. Also 34mm slide-valve carbs; all on a 75 model engine. It dyno'd at 80HP. That said, yours will never get that high with a 3 into 1. I suggest you enjoy it as is. It's a lot of work, a lot of money, and it's really not worth it. If you want to go fast, get a modern bike.


Lane

+ 1 with Lane, enjoy the GT750 for what it is,a very good '70's Supebike,but don't tell everyone...it only pushes prices up not a bad thing if you already have one
Cheers,
Roger

A lift plate will raise all the ports for more top end power, but with a 3 into 1 you won't get there.

Raising ports lowers the compression when the motor is not on the pipe and that loses low and mid range.

Raising compression helps all through the power band and is proportionately more at lower to mid revs. My motor is ported and has 0.5mm off the block and a fair amount off the head and even with a 3 into 1 it works well and with spannies it works even better. Beware of stock head gaskets which are too large in teh bore and you may need to retard the ignition timing a touch, so watch out for detonation with crappy fuel.

im not going for more speed, just more punch, torque. overall more low end grunt.
sorry for renewing this thread,i got back to working on my buffalo......Four mounths later haha

Your setup is about as torquey as it will get. You can get more punch off the low end with a smaller counter-shaft sprocket. Maybe that will give you what you want.


Lane

Just as a point of reference, I have built only 4 street motors so far and on all of them I raised compression by milling the block and head. You may want to order head gaskets from Cometic and fit an electronic ignition, and you will find that raising CR helps a lot at low to mid revs.