Need some help with engine mods......
#1
Need some help with engine mods......
Hey all,
I need some help with my engine, it's just a basic sport engine which came with my Ultima RB.
Anyway, i disassembled the carb to clean it out, and noticed that the barrel in the carb has a 4mm throat (!!). The inlet of the carb is 6mm....but the throat is tiny!!
I see this as a big restriction, and i plan to bore it out to 5-5.5mm......can anybody give me any tips or suggestions as to how i should go about this, and any problems i may get from doing it?? I'm also going to remove 1 head shim to try and raise compression, will i need a different glow plug if i do this??
I have added a tuned pipe, and matched andpolished the exhaust manifold. I also added a higher flow filter than the stock one, and oil and clean it regularly.
I am starting an offroad buggy club (we have an unused BMX track to race on) and i will be racing mainly agains other RTR's such as Evaders (.18 O.S.), and want to better my chances of keeping up.
Thanks in advance,
Jamie
I need some help with my engine, it's just a basic sport engine which came with my Ultima RB.
Anyway, i disassembled the carb to clean it out, and noticed that the barrel in the carb has a 4mm throat (!!). The inlet of the carb is 6mm....but the throat is tiny!!
I see this as a big restriction, and i plan to bore it out to 5-5.5mm......can anybody give me any tips or suggestions as to how i should go about this, and any problems i may get from doing it?? I'm also going to remove 1 head shim to try and raise compression, will i need a different glow plug if i do this??
I have added a tuned pipe, and matched andpolished the exhaust manifold. I also added a higher flow filter than the stock one, and oil and clean it regularly.
I am starting an offroad buggy club (we have an unused BMX track to race on) and i will be racing mainly agains other RTR's such as Evaders (.18 O.S.), and want to better my chances of keeping up.
Thanks in advance,
Jamie
Last edited by jamiekulhanek; 08-09-2004 at 11:30 PM.
#2
BTW its a kyosho GX15 CRG
#3
bump
#4
Tech Apprentice
The carb hole is suppose to taper, if you drill it out to the same bore with no taper you will hurt performance. The taper is called a venturi, the air speed increases as it enters the carb becasue of this taper, leave it alone.
Sounds like you are about to mess up a good motor.
Sounds like you are about to mess up a good motor.
#5
The thing is it doesn't taper......it goes from 5.5mm, to 4mm (barrel)instantly, like a big step, then the bottom part of the throat between the engine and barrel is 4.5-5mm. so this means that the air accelerates through the barrel (4mm) then loses velocity when it goes into the tube leading to the crankcase.....
I haven't done anything yet.....
I haven't done anything yet.....
#6
Are you sure you are not missing the insert (restrictor)?
#7
There is no restrictor for this carb...