View Full Version : Alcohol in a Tri Z?

03-17-2007, 09:46 AM

I have what I thought was a 87 YZ motor. It has the O-ring head gasket. But it has an 8 pedal reed cage and im pretty sure they only used them in 83, but I didnt think they had O-ring head gaskets then. Anyone know how I can tell what I have?


Is I just purchased one of those billet heads from sprock racing with the inerchangable domes 24, 22, or 20cc. Is there anyway to tell how much each dome will increase your compression ratio? Does anyone know what a stock Tri Z head is?


How much compression does it take to burn alcohol. Im thinking about going that route. The bike is set up for drag racing with an 8inch over stock swing arm and a 41mm keihen carb. Im in the process of getting a drag pipe made.

Well there it is. Can anyone help me?

Also im looking for a Zinger tank if anyone has one.

Thanks fellas

03-17-2007, 11:46 AM
you need to talk to brain raffa here, or yamahahondaman (however you spell it) here on the boards as they are the resident tri-z nutjobs.

Bryan Raffa
03-17-2007, 11:46 AM
methonol will do little or nothing on stock compression 190 and above would be ideal, just running a stock head will not work with out being recut, The sprock 20cc dome is the one you want to run, that should put you in the 215psi range.the 22 will get you around 190psi

Bryan Raffa
03-17-2007, 12:01 PM
the 82 yz and the 87 and UP were (O ring)
the 83,84,85,86 were gaskets

If yours is a 87 then its a power valved motor!?

Bryan Raffa
03-17-2007, 12:07 PM
any input on this hrc85250r??? LOL

03-17-2007, 12:11 PM
you can run any compression with methanol (aka alcohol), but, up to a certain point more compression is better, but too much will hurt power. if its properly jetted its harder to detect pinging in a alky motor. and remember in race motors static compression and dynamic compression are totally different things. usually if you want to run alky, the bike is going to be drag only, or if you live in cali you might use it for duning. but, heres the deal. timing is advanced from stock quite a bit because alky burns much slower than gas, so you will need an aftermarket ignition of some type with a powerful spark if possible. also you are going to want porting in your motor that will compliment alky. also you carb need to be a alky specific carb, or you can have your modded. the approx a/f mix for methy is 6.4:1 and thats what your jetting for when your jetting, it will run its best at that point whether you looking for that specifically or not, when your bike is perfect thats about where it is, now, gasoline's a/f mix is 14.7:1, so to effectively convert from gas to meth you need jetting that is more than twice gas across the board. jets alone couldn't do this, so almost every person with a meth bike runs a powerjet if not multiple powerjets. i will add that before you run alky, it can be very hard to start below 50 degrees and if you dont jet it right it will burn holes in pistons, and reading the plug is totally different than with gas. so i guess in conclusion, call somewhere that deals with alky carbs and engines like dave moore or ftz or esr or trinity etc.... and they will tell you everyhting there is to know about your motor, which im sure they probably have all done at some point. alky can be a little frustrating, but it always works out and i really does give about a 15-20% boost in hp. remember you have to flush at the end of every weekend with gas!

Bryan Raffa
03-17-2007, 12:23 PM
heres a tid bit from CT that might help ya..

Because alcohol fuels burn so much cooler and slower than gasoline CT recommend that you increase the compression of the engine to maximize performance, there will be little or no advantage to running methanol on a stock compression ratio. We suggest first checking your cranking compression and then consulting your engine builder before running methanol, some engines will tolerate less compression than others.

Advance the ignition timing. Your results may vary depending upon compression ratio and the sophistication of the ignition system. Proceed carefully and document the timing change by measurement, either by degrees of crank rotation or by millimeters before top dead center.

Minimize flow restrictions between the fuel tank and the carburetors. Remove the petcock from the fuel tank and cut off the filter screen and the reserve stand pipe. Remove any in-line fuel filters or petcocks, use as large a fuel line as you can fit over the fittings on the carbs and petcock.

Check the operation of the slide, make sure that it opens all the way to clear the bore of the carburetor, this is particularly important with modified or bored carbs.

Put taller gearing on the machine. In our experience a methanol equipped ATV will pull a one tooth larger countershaft sprocket. If you run a 13T on gas try a 14T on alcohol.

03-17-2007, 12:30 PM
the 83 has the 8 petal reeds
i pour alittle bud light in mine from time to time to clean the carbon out of the cylinder, steam cleaning:cool:

03-17-2007, 01:01 PM
the 83 has the 8 petal reeds
i pour alittle bud light in mine from time to time to clean the carbon out of the cylinder, steam cleaning:cool:

Isn't that considered alcohol abuse? LOL, sorry for interupting this important post with a silly comment! I'll be quite now......................:beer

03-17-2007, 05:09 PM
Im thinking it is an 87 engine. It is a powervalved with the O-ring head and a slanted intake. Im sort of confused tho. I was told it should have 6 pedal reeds and it has an 8 pedal reed cage. Are they interchangable? Does my 87 have a 83 reed cage? I am going with the 20cc dome and I think in gonna stick with just racing gas for now. Maybe i will go alky in the furture.

by the way thanks for the tips on the alky conversion.....

Bryan Raffa
03-17-2007, 05:41 PM
It could be a DIR aftrmarket reed cage.. there 8 petel