Running carbs pumpside in?
- Thread starter yamanube
- Start date
#ZERO
Beach Bum
- Location
- Florida - U.S.A.
If the Mikuni carbs are mounted in the side draft position the fuel pump needs to be on top with the regulator portion down, otherwise the jet section will constantly drain into the carb making calibration impossible.
waxhead
wannabe backflipper
- Location
- gold coast
I always run carbs that way to stop the exhaust hitting
but i really dont think it makes that much difference to the performance
but i really dont think it makes that much difference to the performance
is drilling an extra hole in the top of the cover plate a recommended thing to do, even if the lower one isnt obstructed, just for better movement of the diaphragm?
It won't affect it, won't hurt, won't help if it's not obstructed to begin with.
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
why do some of the modded carbs have multiple holes?
to ensure they are not obstructed?
to ensure they are not obstructed?
id imagine that if water were to get in that hole, multiple holes would help to drain it quicker :dunno:
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
why not just run a mesh screen then?
got one? You need something that is stiff enough to seal the circumference which isn't that hard to do, prevent the exhaust hose from pushing in, etc.
What's the benefit? A theoretical quicker opening? Weight savings?
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
It just seems like those companies wouldnt spend the $$ to machine their logo in that cover, if only for looks.
wouldnt a sticker be cheaper?
wouldnt a sticker be cheaper?
Stickers come off or are removed, they want their name to stay on the carb.
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
stickers?
http://www.fastcarbs.com/products.htm
I also dont see any additional holes in that diaphragm cover either.
hmmm
maybe it makes no difference.
http://www.fastcarbs.com/products.htm
I also dont see any additional holes in that diaphragm cover either.
hmmm
maybe it makes no difference.
#ZERO
Beach Bum
- Location
- Florida - U.S.A.
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
even the tiny stock hole ( unobstructed) would alleviate any pressure buildup on the atmospheric side of the diapraghm though right?
#ZERO
Beach Bum
- Location
- Florida - U.S.A.
That hole is only 3mm in diameter and the diaphragm is 58mm wide, I'm thinking there might be some restriction.
crammit442
makin' legs
- Location
- here
I think you should start with tach readings and begin drilling extra holes and let us know how many extra holes it takes to make a difference. You could also just start making the hole bigger and bigger until the R's come up and then report the hole size. I wonder if anyone here has an extra diaphragm cover they'd be willing to send you as a test platform. That would be an awesome experiment!
GIL
Power In The Hands Of Few
- Location
- Cullman AL
F it-I just did a test myself, 3mm hole?wtf-I went to a 58mm hole on only the rear carb-guess what-ski ran on frt cylinder only. According to my dyno-it sucked azz. Then I put some duct tape over the 58mm hole and wha la-my dyno says it's all good again. LMAO
ps- I did save some un-sprung weight by drilling the massive hole which I tend to believe will speed my rotation during left rolls on a horizontal plane of 28.73 degree's with an axis pressure of 47.99 kb.
Is there someone here small enuf to put in a carb to check the diaphram timing? Dammit-where's Ronny when I need him!!! He could actually take pics of the dia. in action!
Interesting idea, I have a tach, a drill and a spare cover....I guess I could also just try swapping my Riva cover on my powerbomb to an OEM cover.
Last edited:
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
you would need 2 covers if your running duals.
But that is an interesting test!!!!!!!!!
But that is an interesting test!!!!!!!!!