Mikuni 34/ 420 predator question.

[mrguy]

Here it tis...sounds awesome, but dumps fuel out of the bottom overflow AND seems to run better without the mikuni fuel pump (Gravity feed). Is this the case with a mikuni flatslide? Is there a workaround for a karting/atv application requiring a fuel pump? Thanks

 

[Stangrcr1]

Same thing I found with a Mikuni on my 390. It seems the Mikunis can't handle the added pressure of the fuel pump. The float is not strong enough to close the needle, unless you adjust the float lower. Best solution is to raise the tank and just gravity feed, or in a kart, run a return line to the tank. Tee off the fuel line at the carb inlet and run it back to the tank. That way the excess gas will go back to the tank instead of into the carb and overflow.

 

[mrguy]

Same thing I found with a Mikuni on my 390. It seems the Mikunis can't handle the added pressure of the fuel pump. The float is not strong enough to close the needle, unless you adjust the float lower. Best solution is to raise the tank and just gravity feed, or in a kart, run a return line to the tank. Tee off the fuel line at the carb inlet and run it back to the tank. That way the excess gas will go back to the tank instead of into the carb and overflow.

Thanks! What should I build to stick this to? Kid-size Chinese quad? Full cage kart?

 

[Stangrcr1]

This is what mine was in.

Build whatever you want. I have been thinking of putting a clone in a chinese quad...

 

[mrguy]

That thing is bitchin. What size sprocket in the 50s? Bully clutch?

 

[mrguy]

I saw the other photos it looks like a torqueaverter. Great build.

 

[Stangrcr1]

Actually it had a snowmobile clutch. Comet 108C driver and an Arctic Cat secondary.

Build it any way you want, but for a caged off-road style cart, I would run a TAV of some kind.

 

[boostdoctor]

Nice looking motor. Your air filter looks a bit restrictive for a 420 though.

 

[mrguy]

Nice looking motor. Your air filter looks a bit restrictive for a 420 though.

eBay piece from Taiwan figure it will be ok until I decide what to build or stick it in,:thumbsup:

 

[ole4]

mikuni sells a needle and seat that will work with a fuel pump, I have one it my kart without a bypass return and it works great. It takes more PSI to open the needle as it is smaller and the opening is smaller.

 

[Stangrcr1]

mikuni sells a needle and seat that will work with a fuel pump, I have one it my kart without a bypass return and it works great. It takes more PSI to open the needle as it is smaller and the opening is smaller.

Thats great! Part numbers? Where did you get it?

 

[ole4]

Sudco here is a table for the ones available for a TM like I used but they have them for all different models. I used a 1.8 I believe

Applications: TM32, TM34, TM36, TM38 Flat, 39 & 41 Pro
(no accelerator pump on carburetor)
Order No. Mikuni No. Size Application
002-703 786-46001 1.5 -
002-702 786-46001 1.8 -
002-704 786-46001 2.0 -
002-706 786-46001 3.0 -
002-705 786-46001 3.3 Std on TM32, TM34, TM36
002-707 786-46001 3.5 Std on TM38
002-709 - - KV-10 O-Ring for Needle Valve Seat

 

[125ccCrazy]

local dirt bike shop here told me to use a 1.5 with the pump.. also agree on the airfilter, I've tried those and they don't flow real well..a nice foam filter or a larger canister shaped filer will perform a lot better...

 

[mrguy]

got the 1.8 from Niche Cycle...same result (flood). I think this motor will end up in a gravity feed switch anyway.

 

[minidragbike]

This is what mine was in.

Build whatever you want. I have been thinking of putting a clone in a chinese quad...

Best looking DB I ever seen

 

[Stangrcr1]

Best looking DB I ever seen

Thanks! Too bad I never got to take it down to the spot...

 

[naterater]

6.5hp pred 22mm mikuni carb

same problem i bet , the float doesnt have a retainer clip on the needle valve so when you take off the bowl you find the needle at the bottom cause it falls out and the gas pours out , happens to me to . matter of fact thats why im here i was gonna ask someone if they new of a better carb different maker. i always have to adjust it , and when i ride if it loads up with gas im walking and that sucks no one likes pushing the bike lol xD its gravity fed also and lastime the needle came out i found the jet in there with it