Topic: Performance carbs or junk?

[dragracer]

I was browsing around on a bike parts for sale page on FB a few months ago and came across a set of interesting looks carbs. I've never heard of the brand before,(Chinese knockoffs) but they looked to be something i thought i'd try and the price was right for new, unused so i bought them.

Koso is the brand stamped on the side and they are 32mm carbs. Not racked but individual carbs like the Mikuni VMs. To use them in a multi cylinder arrangement like the sOHC, the old style 750 carb cables look like they might work. Anyway, I'm going to give these things a try on the next engine i build to see if i can tune them in a perfomance application.

They might be junk on the other hand and i would have wasted $150.

Check out the pictures and then flame away.

[johno]

Give em a go mate, nothing to lose
with my Mikuni TM 32 the genuine honda KO cables I bought didnt fit as the cables inner and outer was too fat, so I made up a fresh set of lightweight 1 to 4 cable set up using a generic 1 to 4 cable junction block from a US ultra light plane company, worked fine and was cheaper than the honda cables I purchased and now on the shelf never to be used pile.

[dragracer]

Give em a go mate, nothing to lose
with my Mikuni TM 32 the genuine honda KO cables I bought didnt fit as the cables inner and outer was too fat, so I made up a fresh set of lightweight 1 to 4 cable set up using a generic 1 to 4 cable junction block from a US ultra light plane company, worked fine and was cheaper than the honda cables I purchased and now on the shelf never to be used pile.

I'm going to also check my spare Lectron throttle cables to see if they will work on these carbs. One issue i see is the jets do not have any markings on them so its a mystery as to the size. I'll try to look up the specs online to see if any are listed and go from there. Who knows, they might work well after some tweeking. They were cheap and bigger than stock carbs so its worth a shot.

I'll put these on the junkyard engine I plan to build over the winter from parts I have laying around. The engine will go in a cobbled together chassis, assembled with spare pieces and parts. It may not win any show awards but i'll do my best to insure the package is safe, easy to ride and most important of all, consistent enough to win rounds. And yes, you will be required to sign a waiver releasing me from liability along with an agreement to share in your winnings (60%, me/40%,you- split)- lol.  In the end, I hope to bring this bike along to the Cup races next season as a spare bike in case someone wants to join Bill, Trey and I on our rag-tag SOHC drag racing team- a subsidiary of the infamous Sam Green Racing team.

[dusterdude]

Interesting stuff frank

[dragracer]

Interesting stuff frank

If they work Mark, it could be another avenue for the SOHC'ers to pursue for better carburation. Lets keep our fingers crossed.

Now synching these carbs might prove to be a slight problem. I'm sure i'll work out some type of vacuum port in either the carb body or the boots.

[dragracer]

Found this bit of info during a search for carb specs:


Carburetor KOSO 32 flat
slider
connection engine: 36mm, con..
..nection filter: 55mm,
main jet 142, idle mixture jet
42
 

 
The design of the KOSO flat slider carburettors is based on the KEIHIN PWK series and includes many of the advantages of the original. They stand out thanks to their compact design, are fitted with a chrome slider and a CNC milled intake duct. Thanks to the power jet, the engine can be tuned more leanly in the middle rev range without making it excessively lean at full load.

[TurboD]

I am curious to see how they work out and how well you like them, It will be hard to pry me from my CV's.

The junkyard engine, cobbled together chassis with spare pieces and parts setup sounds like my bike..

[dragracer]

We'll see what the winter time project nets with these carbs. The power jets might be very helpful to smooth out fuel issues throughout the run. I'm not into dyno tuning but this might be an idea candidate for some afr pull's.

[triple]

I  hope you can get them to work..
I tried another Chinese knock off of the Keihin PWK carbs ( oko brand )
30mm venturi fitted onto a 250cc twin , 2 stroke racer BUT there was no way I could get the carbs tuned.... way too erratic....done some research and found other people had the same issues.

Also had the same issues as you regarding no marking on the pilot or main jets SO I bought a complete set ( 10 of ) jets but still no progress.

Looks like these carbs are going to the junk pile.

Keep us in the loop with your  carbs. They are clearly a low cost alternative to the main stream carbs out there now.

[turboguzzi]

there's chinese and there's taiwanese. the last make motors for BMW and triumph (and surely others), not to mention that the whole high end bicycle industry is based there, SRAM, rock shox,  carbon, Ti and alu frames.
they seem to be taiwanese and wouldnt hesitate, just tell us where you find them at 37$ a piece.....

making the linkage though would be a bit of work though

[dragracer]

there's chinese and there's taiwanese. the last make motors for BMW and triumph (and surely others), not to mention that the whole high end bicycle industry is based there, SRAM, rock shox,  carbon, Ti and alu frames.
they seem to be taiwanese and wouldnt hesitate, just tell us where you find them at 37$ a piece.....

making the linkage though would be a bit of work though

I'm hoping a Lectron carb cable will work on these. If not, I'll get my machinist friend to modify the slots in the slides to fit the old Honda SOHC cable. I'm going to put these on something.

[turboguzzi]

mind telling us where to buy?
pm me if you dont want to give free advertisement
in japan webike they are 69$ for the round slide