39mm alky carbs to big for 4mil?

[ryansedy]

wondering if keihin 39mm alky carbs are too big for my 4mm thats currently in the shop. it has t-5s, port polish, vforce reeds. be riding it mostly in sand.

[screamingcub]

I don't have any experience running alcohol, but 39mm carbs sound kinda big for stock cylinders and T-5's.

I've got a 421 cub on race gas, and 35's are working great.

[sleeper06]

I run 39s on gas ,but jeff told me that I could use same size carbs on my set-up BUT your port work is key who did it and what kind,ditch the t-5s

[sheefreak]

I ran 39PWK's on alky on a 4mill Patriot Drag ported motor w/Shearers and ran great. I second ditching the t5's.

[bansee fever]

why ditch the T5s he said he was gunna be mostly sand riding? i love my t5s for duning

[sheefreak]

why ditch the T5s he said he was gunna be mostly sand riding? i love my t5s for duning

 

I assumed he meant he will be dragging on sand. If he is going to run alky on a duner, he better have a big auxillery tank bolted to the back of the quad, or stop and fill up every 20 minutes.

[dajogejr]

I assumed he meant he will be dragging on sand. If he is going to run alky on a duner, he better have a big auxillery tank bolted to the back of the quad, or stop and fill up every 20 minutes.

 

 

Yep...

39's on alky will work fine. JT had 39s on gas on his 4 mil cub and it ripped.

But I think 39s' on alkys with T5s is a waste to be honest...with or without the big gas tank.

 

Something else to consider...

 

What compression ratio AND cranking compression are you at?

What is your squish?

How much timing are you running. Are you planning on all out duning, drag race only, etc?

 

I know you asked about the carb size...but there are other factors in the equation a lot of us have gone through and are offering to help curb your learning curve...

[ryansedy]

The real reason i want to run alcohol is..where i work we have a methanol tank, and easily available to me for under $2.00 a gallon verse race fuel at $8.00 a gallon.

 

Really ditch the T-5s huh? I would totally but like i said my engine is in the shop right now. I dont have the extra $500 to throw at it for pipes..but i definatly believe u guys and probly will down the road when the motor is done.

 

Dont know the squish..as the motor is being built right now the engine builder is asking me what i want. i want to run alky cause is cost effective for me and easily availible.

 

I know you guys are the pros so...let me know...Alky or Race fuel? too much hassle with alky?

 

The motor was ported & polished previously to me owning it..i believe mostly duning port?

 

Its not gonna be a drag bike, but who doesnt drag in the sand right? I want the ridabilty and still be able to drag my friends and other banshees in the sand...but by no means is it gonna just go up then straight back down..

 

Thinking maybe ill just convert my stock carbs to alcohol and see if that works out???

39mms seem to big for my stock cylinders but was wondering cause i can get a good price on em???

[uwenr]

The real reason i want to run alcohol is..where i work we have a methanol tank, and easily available to me for under $2.00 a gallon verse race fuel at $8.00 a gallon.

 

Really ditch the T-5s huh? I would totally but like i said my engine is in the shop right now. I dont have the extra $500 to throw at it for pipes..but i definatly believe u guys and probly will down the road when the motor is done.

 

Dont know the squish..as the motor is being built right now the engine builder is asking me what i want. i want to run alky cause is cost effective for me and easily availible.

 

I know you guys are the pros so...let me know...Alky or Race fuel? too much hassle with alky?

 

The motor was ported & polished previously to me owning it..i believe mostly duning port?

 

Its not gonna be a drag bike, but who doesnt drag in the sand right? I want the ridabilty and still be able to drag my friends and other banshees in the sand...but by no means is it gonna just go up then straight back down..

 

Thinking maybe ill just convert my stock carbs to alcohol and see if that works out???

39mms seem to big for my stock cylinders but was wondering cause i can get a good price on em???

I have done both, when I first built my bike i converted the stock carbs to alky and it ran great. Then when I got some more money i went to 39mm pj. It ran better put cant complain about the stock carbs. T5s are a great pipe but if your going for the racing which it sounds like you are you will need to go to a bigger pipe like CPI or shearer.

[dajogejr]

Keep the compression and timing down and run pump/race fuel.

Methanol is not in your future yet....

You'll burn through it at least twice as fast as gas, so it just doubled in price realistically.

Plus you'll use more oil (methanol is corrosive and it's a good idea to burn more oil)...then, are you familiar/aware of the purge routine to clean the meth fuel out of the bike?

[ryansedy]

Keep the compression and timing down and run pump/race fuel.

Methanol is not in your future yet....

You'll burn through it at least twice as fast as gas, so it just doubled in price realistically.

Plus you'll use more oil (methanol is corrosive and it's a good idea to burn more oil)...then, are you familiar/aware of the purge routine to clean the meth fuel out of the bike?

 

 

Im thinking the same...i know how corrosive it is, as i deal with it at work. I dont have any friends that run it in there quads. but know alot of guys that run it in there modified cars at the dirt circle track, alot of these guys are switching to E85??? anyone ever heard of this? my boss was telling me some guys at the track are switching to it cause its lets corrosive. theyll burn less fuel, but still get to run higher comp.