I modded a predator 212 to put on my mini bike to drag race it 1/8 mile. Mods include fuel pump, billet flywheel, billet connecting rod, mod 2 cheater cam, 18lb springs, high flow carb, air filter, aftermarket header and RLV muffler. The engine is running on 100 octane racing fuel. I am running a 19 drive to 55 driven gear ratio. My question is how do i make it run on methanol? Is it worth it running on methanol? Any help would be greatly appreciated.
Mod 2 for drag racing?
When you swapped out the rod did you take that opportunity to go longer and also hook up a flat top piston?
If not the high octane fuel is actually robbing you of power.
IMO for racing use low lift cams are a waste of time, ported or not if you what to get air/fuel into these motors you need to jack the valve open.
If your not high compression there's even more reason. A 0.275'' lift cam with 1.3:1 rockers gets you 0.3575'' which you can just do on a stock head with 26lbs springs.
Whats a 19 drive? is that a sprocket?
When you swapped out the rod did you take that opportunity to go longer and also hook up a flat top piston?
If not the high octane fuel is actually robbing you of power.
IMO for racing use low lift cams are a waste of time, ported or not if you what to get air/fuel into these motors you need to jack the valve open.
If your not high compression there's even more reason. A 0.275'' lift cam with 1.3:1 rockers gets you 0.3575'' which you can just do on a stock head with 26lbs springs.
Whats a 19 drive? is that a sprocket?
With a 19/55 drive set up, you can't have a whole bunch comin' outta the hole. Have you tried lowering the driver gear? Seems to me like it should be half, 10 or 11 tooth....unless you have a 8" tall tire! 1/8 mile you need a quicker start, get out of the hole harder, and rev the guts out of it at the end
Flat Top high compression
To me a modification or mod is a power adder, Billet flywheels and rods don't throw up power numbers on a dyno. you can run the flat-top but you need to mill the block down 0.040'' If you have the +0.020'' rod mill the block 0.020''. with a 14cc head you'll be around 12:1, nice!
To me a modification or mod is a power adder, Billet flywheels and rods don't throw up power numbers on a dyno. you can run the flat-top but you need to mill the block down 0.040'' If you have the +0.020'' rod mill the block 0.020''. with a 14cc head you'll be around 12:1, nice!
Listen you do not need to run 100 octane gas , you don't have the compression for it . And running meth is a lot of work to do even after the motor is set up for it . You can't leave the meth in the tank or carb , it all has to be flushed out when your done running it . Just a big PITA.
Get a flat top piston , mill your head and a bigger cam and run race gas .
You will never be able to turn a 19 with that setup without stalling it to around 4-5000rpm ang a real smooth engagement. You need about a 15 if your running doodle bug size tires or maybe a 17 if your running regular mini bike tires height wise. And methonal will make it go faster but you can't leave it in and will have to change your oil A LOT! I drag raced mini bikes back in the mid 90's with a 13hp Honda. It ran 8.60s in the 8th with a 19/58.
So many folks want to stick some jets in and start running alky. There is so much more to it. As stated above, you need monster jets and monster compression to run alky. I have friends that wonder why I don't, and the reason is simple. Wulf hit the nail on the head. Alky is a pain in the butt if you're not racing. I'm not willing to break down my motor and "freshen" it up as often as would be needed. I have a 20 over rod, a ft piston, and I'm using the 14cc head, and I run pump gas. It's fine.
I agree, you need to swap gears. If you're running a good racing clutch, it should be as simple as buying a new sprocket for the clutch. I'd go with 10 or 12 tooth, but that's just me. If you're running a cheap clutch and trying to drag race, invest in a good clutch. Most people don't realize how expensive it is to build a solid race motor. They also don't realize how much work goes into maintaining one. You can build a strong, fast motor without going all out. As recommended above, swap out the high octane stuff for pump gas and swap gears. You'll feel a lot more out of the whole.
Let me say, I'm not a drag racer. I've never even taken any of my motors down the strip (I just really enjoy building these little motors, and I have fun running them around the neighborhood and at the campground with buddies. It seems to me that with your current gearing, you may not be reaching your motor's full potential before the race is over. What kind of rpms are you turning at the end of the strip? I'd think you'd need more room to get them to where they need to be.
Good luck. Let us know what swapping gears does for you. I think you'll like it!
I agree, you need to swap gears. If you're running a good racing clutch, it should be as simple as buying a new sprocket for the clutch. I'd go with 10 or 12 tooth, but that's just me. If you're running a cheap clutch and trying to drag race, invest in a good clutch. Most people don't realize how expensive it is to build a solid race motor. They also don't realize how much work goes into maintaining one. You can build a strong, fast motor without going all out. As recommended above, swap out the high octane stuff for pump gas and swap gears. You'll feel a lot more out of the whole.
Let me say, I'm not a drag racer. I've never even taken any of my motors down the strip (I just really enjoy building these little motors, and I have fun running them around the neighborhood and at the campground with buddies. It seems to me that with your current gearing, you may not be reaching your motor's full potential before the race is over. What kind of rpms are you turning at the end of the strip? I'd think you'd need more room to get them to where they need to be.
Good luck. Let us know what swapping gears does for you. I think you'll like it!