MIKUNI 25mm CARBIE MANUAL.

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Cactus Jack

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The symptoms you describe seem to be a common problem with the Mikunis - the bog is caused by a hesitation in the fuel delivery due to a sudden vacuum drop when the throttle is applied ! Hoss2k4 from Arizona had the same problem on his 2005 Pitster and it still persisted even after he received a new replacement Mikuni carb from Pitster ! He tried EVERYTHING for months , then tried a Keihin carb off his CRF88 and the problem was solved ! The bike (125 GPX Jialing engine) became super responsive and crisp and clean revving from idle to peak revs - just like a Honda ! He said it chucked wheel stands into 3rd gear instead of bogging like it did with the Mikuni . The pitbike Mikunis are just a bad design for 4 strokes whereas Keihins are well sorted and engineered to suit them .
 

Quick-Prox

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thats a really good page now i no when my bikes running lean or rich. thanks heaps for that.. cheers your mate PJ
 

skintag9

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Does anyone know any good motorcycle mechanics around melbourne that could tune my bike properly (Atomik moto x)? I had to replace the throttle cable and I have not been able to get my bike to run correctly since. I played with the mixture screw (thinking it was an idle screw) which has compounded problems...
 

SIKSPAC

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does anyone know whats wrong with my mates bike????
It runs all good but then the bowl will fill up and keep filling causing him to lose alot of fuel????
Its got us stumped whats wrong with it ay....
Oh its on a AGB-29......
 

deon.jacob

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i got a question and yes i have done some research but no luck. My 125cc ducar motor will run for 45min to 1 hour and then lose power. It will idle fine but will not take any load or Rev (and no the choke is not on). Have read many threads on this issue and have come to the conclusion that my carbi may be blocked and need a clean. My Question is, how easy is it to clean and what do you do exactly, ive have never cleaned a carbi before and would be great if some could list what i clean it with, tools required and step by step process.

Any help would be great!!!!
 

unit_mx

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Im experiencing severe problems with my minkuni ,she idles unbelievably high even without a idle screw with vibrated out and with absolutley no pull from the throttle cable,Then when i rev it in both choke positions the thing just cut outs on the slightest of revs.Can any one help me with this shithouse problem or am i better of just buying a kehin carby? cheers
 

stumbows

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I've been noticing that the 24mm flat side kehin carbys are going for more than the 30mm ones on eBay why is this? are they better?
 

goneriding001

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gday fellas just bought a new bse 140 with mikuni carb when i filled her with petrol then turned fuel tap on petrol started to pour out of the bottem hose.

bottom screw is all the way in.
tried different screw same thing happend.
i blocked the hose then carby flooded.
took 4 a quick spin anyway at slow speed petrol still comes out but at high speed it stops then i come to a stop and it starts again within ten seconds.
turn the fuel tap off it emptys the carby then stops.
i have not touched the carby yet.

any and all advice would be appreciated as im at my witts end and about to ripe that little sucker apart.

thanks.
 

THUMPY125

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bad news, ya bowl float is stuck, you can try turning off the fuel draining the petrol out of the carbi via the little screw at the bottom. then tighten the screw and turn the furel back on, if this doesn't fix it pull the bottom of the carbi off by the 4 screws and push the float so as it frees up, if you are skilled you could try and place a small bit of petrol in the bowl whilst it is apart and put it back on so the float will float. REMEMBER how things go before you take them apart:D
 

Sidney

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You can try tapping the bowl of the carbie with a spanner it sometimes works.
 

goneriding001

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tried that didnt work still doing same thing.
come on fellas bout ready to start kicking it and i dont want that to happen.

this one has got me seriously stumpt
 

goneriding001

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tried putting little bit of petrol in the bowl like suggested (feel like a fool for trying that one) even tapped it with a spanner like suggested (felt like bigger fool) come on fellas need real help sick of pulling the little bitch apart help me please.

solve my problem and i will buy ya a beer when ya down my way.
 

Sidney

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Take the carbie off (2 bolts) unscrew the throttle cable and undo the 4 screws holding on the bowl. Then just wiggle around the float.
 

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