400 Yoshimura Jeting sizes ??

[Lynxx]

Hi, i have a 1992 Japanese import Bandit 400v and it has a full Yoshimura Cyclone system on it, but it runs rich.
I have stock Main Jets, Stock pilot jets and pilot screw is turned at 1 and a 1/4. Carbs are balanced too.

What can i do to stop it running so rich ?
I am also pretty sure the o-rings are good, as the inside of the carbs look brand new (the plastics still white) and the o-rings are still flexible and not cracked or flat. Soon as i get some spare cash ill buy o-rings as i am already buying a few parts for it at the moment.  Ah and she does run fairly well other than the idle changing sometimes, and pulls in all gears, red lines at 14,500rpm in gear and 10,000rpm in neutral.

Ohh and she does start without choke most days, but runs bad until warmed up (usualy takes the choke or your hand on the throttle to keep it running until warmed up)

Does anyone else have a Yoshimura Cyclone system on a Gsf400v ? if so please tell me what you did to your carbs to stop it running so rich.

heres a photo

[interfuse]

I have a similar yosh exhaust but no crossovers on the header. Take a look for needle jet wear when you have the carbs apart. Replacing them solved my running rich issue.

http://forums.banditalley.net/index.php?topic=11225.0

[Lynxx]

yours has twice the mileage of mine, mine only has 25,000 km so i don't think they are worn out. The inside of the carbs look relatively new, it was exported from japan in 2001 and since then has been someones project and hardly seen the road. Japanese have strict laws so they probably kept the thing like brand new.

[Lynxx]

what mileage should i expect from it ?? maybe im used to driving my old 200cc 2 stroke (which was a whore on fuel too). I only got 60 miles out of roughly 2 gallons yesterday. Surely it gets better than 30 miles per gallon ?

[Lynxx]

found one problem, one of the carbs had the needle floating.. the plastic thingy that holds it down had shifted. would that make my fuel mileage go down so low ?

also i have clips on the needles and they are all set half way. i lowered them all the way and set pilot screws to 1 turn. lets see how this goes.

[interfuse]

I typically get 40 mpg.

[Lynxx]

My sprockets are size 12 on the front and stock on the back ?? haven't counted the back yet.
But to achieve 50mph in 6th gear i have to be doing 8000rpm. If i change the front sprocket to a 16tooth this will hopefully lower the revs to 50mph to 6000rpm in 6th gear. Thus helping my fuel mileage correct ?

And if im thinking right it adds 33% top speed, making my new top speed close too 150mph (if the engine has enough power to turn the wheels that fast).

I was wrong in thinking the jetting is wrong, but my assumption come from the amount of fuel it burns.

Also my idle is funny now, it will sit at 2k idle and then drop down and die after running a while. I have balanced the carbs again, the clip on the needle is set to half way and the mixture screws are at 1 turn (if i turn them out it gets even worse). Spark plugs are perfect color and exhaust is sooty. Whats the problem ?

[Lynxx]

Yeah a guy from Greece told me hes using #90 main jets and his still runs rich ! I don't know what i am running because the jets are rough and ineligible. I may try that, i can test any size jets for free at my bike shop because i know the owner very well. And i can also get all 4 jets for only 4 GBP. But it seems the bikes running right now other than what i mentioned about the idle. It has brown nice color spark plugs so main jet is not out of size.

[Lynxx]