Carb relocation, longer intake runner

cityevader

New Member
May 11, 2008
170
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0
Santa Cruiz, CA
I'm about to try to move my carb to, say, the rear panier rack. (it should be below the fuel petcock i hope) Half the reason to move it is to have room to experiment with intake mufflers. The other half of the reason is to increase the runner length from carb to motor (maybe 8 inches longer). This should boost power in the lower RPMs.
My "problem" is that I live in hill country. Lots of rolly-polly up and downs, and there is never a time that I'm flat out on the flats. Either the motor is over-revving or bogging down. So if the powerband could be broadened a bit so that the other half of the time it isn't bogging...sweet! The other half of the time is gravity assist, and the 44t, "80cc" is into it's sweet spot at 30mph.
I remember one post with a (ridulously long) runner length of three feet with undesirable characteristics. But going from 4 to 12 inches? hmmmm, should work, right?
 

cityevader

New Member
May 11, 2008
170
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0
Santa Cruiz, CA
Allow me to say I'm not looking for some "backdoor" power boost that no one has come up with yet.

My frame mount engine is so cramped...air filter housing hits frame and can barely be removed, and spark plug wire is nearly against frame as well. So I'd really like to get the carb out in the open. (to experiment with intake muffler, as it's louder than the exhaust). Figured the existing intake is 3/4" O.D. so should be easy enough to route some hose to another section of pipe with a mounting bracket soldered on, and clamp the carb to it.

My main question is if somebody HAS tried it, did they notice any improvement in the power band, as in larger engines, increases length improves performance at a lower RPM) or did performance decrease?. Again, Only about an 8 to 10 inch increase to intake length.
 

cityevader

New Member
May 11, 2008
170
0
0
Santa Cruiz, CA
I would try the other end of the engine and go for a pipe
Either a Moussecan style or a pipe
47cc Pocket bike Performance Pipe.
Mousse can style. Use a 1.5 to 2 inch pipe or a fire extinguisher
Mousse Can Muffler

I use the mousse can style from spad to the bone.
Start Here

The front of your stock muffler and a new back end.
YEAH, THANKS!!! I've been searching forever to get something like this site for mousse can mufflers I saw so long ago!!!
The SPAD RC airplane reminds me of back in the day, early high school, 1990, using 2-inch gutter drain pipe and bamboo, fishing pole, arrowshaft, aluminum c-channel, and what-not to make pod-and-boom airplanes. If we had a crashed plane with decent wing, whip out a new fuse and fly again tomorrow. Used to cut new foam wing cores with hot wire cutter. Probably about 80 kits and scratch-builts over a 6 year span....and only a single fly-able plane stashed in the attic somewhere.
Thanks for the memory-shake!
 

KiDD

New Member
Apr 9, 2008
3
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0
I had to relocate the carb on my bike for clearance, My spark plug boot barely touches the brake lines and has rubbed a bit of plastic off the brake line. I am using the CJ7Y plug BTW.

Check out how I did it... My MB PhotoStream It's not the prettiest, or the best. I'm thinking of ordering two intake and chopping them up and getting them welded together to it points out to the side like it does on my bike. The problem I have is the vibrations are amplified by the vinyl hose.
 

Norman

LORD VADER Moderator
Staff member
Jan 16, 2008
2,605
2
38
67
pampa texas
My intake to clear the frame. steel home made intake using socket head capscrews with the carb off set to clear frame





 

Andyinchville1

Manufacturer/Dealer
Dec 26, 2007
502
1
18
Scottsville, VA
HI,

I did the super long intake....gave excellent idle torque and very slow speed torque BUT nothing but bog much faster than idle speed....I say go for the shorter length....it may just be what we are looking for!....I have been soooo busy with work or I would have done it by now...

Andrew
 

protow

New Member
Jun 25, 2008
24
1
0
Seattle,W
www.ramlyn.com
well i had an issues with my bike when i mounted the motor to it this weekend . i bought a brand new schwinn creek. its had a nice back bone the flowed nice with the gas tank on it.. but the down side was the crab would not fit at all. so after about 6 hrs of trying to make and think of making a new intake my 9yr old sone was playing with a 3/4 heater hose and then it came to me...so i put the heater hose on the intake and added a 3/4 in peice of pipe so the carb would bolt to it and BOOM it look,fit and RUNS GREAT...

ill upload a pic of the bike and crab when i get home...
 

Norman

LORD VADER Moderator
Staff member
Jan 16, 2008
2,605
2
38
67
pampa texas
I can make you one like what I have on my bike for $30.00 it will be all out of steel. let me know if your interested.
Norman