blaster build gone wild! pics also
- Thread starter 1bad442
- Start date
not for alchohol its not
I run a 38mm on my 406cc motor.
If your goin drag only then i guess its cool you are losing alot of intake velocity.
This hurts the low end.
At any rate grade A work all around bud.
for normal riding i will have a pwk 36 on it for sand racing i will run the 38 with alchohol u need to keep in mind alchohol burns at twice the rate of gasoline so u need a bigger carb that will flow enough air to match the alchohol requirements but thanks for the tip
Well, alcohol you need more FUEL flow but not necessarily any more airflow. The optimal AFR for alcohol is a tad richer than gasoline and there aren't as many BTU's in alcohol (which means you need more fuel for the same amount of heat and expansion) but your engine can't consume but so much volume (air+fuel) no matter how big your carburetor bore is.... ~244cc even at 10,000 rpm is still only 86 CFM so a huge bore carburetor isn't required as much as a HUGE jet is required.
The equation gets even worse if you start using even more exotic fuels. Nitromethane (for example) has an optimal AFR of 2.4:1 because it's a partial monopropellant and very little heat in it. The same carburetor bore (38mm) would need the equivalent of 8 main jets worth of fuel flow into the same amount of air. Still not a bigger carburetor throat though...
The equation gets even worse if you start using even more exotic fuels. Nitromethane (for example) has an optimal AFR of 2.4:1 because it's a partial monopropellant and very little heat in it. The same carburetor bore (38mm) would need the equivalent of 8 main jets worth of fuel flow into the same amount of air. Still not a bigger carburetor throat though...
i will agree u have valid points but my motor is bigger than 244 and i have a long rod which will raise the rpm ceiling also im looking for peak horsepower which ct racing has proven u can get using a 38 mm over a 36 mm
For a combo quad your switch from 36 to 38 will probably be a beautiful solution. Instead of trying to size one carburetor to do both tasks you can setup each carburetor for a particular use.
I do have a feeling that for the drag strip some more power could be realized by going with an even larger carburetor. You won't be worried about low RPM flow fluctuations or air velocity for off RPM accelerations. It's going to be wide open the whole time...
I do have a feeling that for the drag strip some more power could be realized by going with an even larger carburetor. You won't be worried about low RPM flow fluctuations or air velocity for off RPM accelerations. It's going to be wide open the whole time...
yeah i feel the 2 carb setup will work the best myself. what difference did u notice after installing the long rod in yours?
My engine was built before I bought the quad. It was a 240, ported, head cut, long rod, timing advanced, blah de blah de blah....
I bought it blown up and stuck a stock top end on it. I can't really say what advantage there is by having the long rod as I never rode it before. I'm fairly sure that it's like most things, the advantage is best realized when coupled with other stuff. Some stuff I no longer have on this engine...
I bought it blown up and stuck a stock top end on it. I can't really say what advantage there is by having the long rod as I never rode it before. I'm fairly sure that it's like most things, the advantage is best realized when coupled with other stuff. Some stuff I no longer have on this engine...
tmx 38 mikuni
are you sure this is gona fit ? i had a 34mikuni and i had to bring it back
the bottom of the carb hits the engine caces i ended up buying a keyhin pwk34mm
Everything i play with runs meth.
Git er done
who would u recomend to set up a meth carb im gonna run m5? ive been told rdz does some nice work
RDZ set up my Keihin 38mm stryker.
They do great work.
Since the main jets have to be custom drilled, have whoever sets it up for you also send a jet kit.
The jets on my bike are so big that they will EASILY strip when tightening them down because there is no metal left where the threads are.
Hand tighten them down with some blue loctite and then wrench'em tight only another 1/8th turn.
I use a FTZ 39/40 taper bore, a bigger petcock & fuel pump with meth on my yz250 Blaster. I think meth may be a good choice for your motor since you may be pushing the temp limits on gas depending on how you're gonna ride it. Don't know, just thinkin.
Yup, maniac is good. I wuz thinkin short drag type stuff, show yur quick ... no problem. High gears, soomin around, show yur speed ... no problem with lotsa air movin across the fins. Low speed, high rpm, tight trail type stuff, workin like a dog with low air flow might get warm. Just sayin cuz our sand trails eat up lotsa nice, well built motors.
Great build ya got goin!
Great build ya got goin!
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