rentedshoes
Been Around the Block
I am looking to upgrade the carbs on my cb175. It seems the general consensus is: if not stock, then Mikuni. Does anybody know what size/style works best for street use on these little bikes?
CB 175 & Mikuni Carb
- Thread starter rentedshoes
- Start date
Whay do you think you need different carbs? The reason I ask is that we built a 200cc CB160 and it ran stock (more or less) CB160 carbs and it was really fast.
The most common up-size on carbs on those bikes appear to be 22mm Keihins, but Mikunis would work just as well.
We have one bike with 26mm CB77 carbs and another with 26mm Mikunis (which are much larger) but those are full on race bikes. That motor will tolerate larger carbs, but you can clean up stock carbs and make them work better.
Making what you've got work better is a good start and if you take the head off, raise the compression and clan up the ports doesn't hurt either.
The most common up-size on carbs on those bikes appear to be 22mm Keihins, but Mikunis would work just as well.
We have one bike with 26mm CB77 carbs and another with 26mm Mikunis (which are much larger) but those are full on race bikes. That motor will tolerate larger carbs, but you can clean up stock carbs and make them work better.
Making what you've got work better is a good start and if you take the head off, raise the compression and clan up the ports doesn't hurt either.
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rentedshoes
Been Around the Block
The reason for wanting to improve the carbs is 2fold. First, during the carb overhaul I noticed that one of them is missing a tiny spring loaded flap on the choke slide. It seems that repairing this will be next to impossible without replacing the carbs. If you are going to replace them why buy more stock parts? 2nd, everybody raves about smother and stronger power delivery. If anybody can tell me different I am all ears. No sense spending money on shit you don't need.
rentedshoes
Been Around the Block
I will look into it a little further and let you guys know how it shapes up. Thanks for the input so far!
rentedshoes
Been Around the Block
so the consensus is 20mm? What is that measurement?
rentedshoes
Been Around the Block
I dug out the micrometer and measured the slide as it was easiest to get to. It measures 19.524mm. This would lead me to believe that this is a 20mm carb. Is my logic sound? What would happen if I installed a 22mm carb? Would it really make a difference with a mostly stock configuration? I really appreciate the input so far.
Big R
Heaven is so far away.
Teazer or PJ (among others) will have a better answer than me, but a 22mm would be too big for a stock motor. Even new vm20's will perform much better than 35 year old originals.
I think it has to do with how much more air and gas will be sucked in to the stock combustion chamber.
I think it has to do with how much more air and gas will be sucked in to the stock combustion chamber.
rentedshoes
Been Around the Block
That is the info I was looking for. Thanks Rich. I would hate to buy the wrong size carbs then waste a bunch of DTT's time trying to dial it in. I will prolly pick up some VM20's and hope for the best. I think fresh carbs will do that bike a world of good. Thanks again.
