ok guys i cant get the jetting right and ive tried everything.. check it out, i switched to a carb mount UNI the one stage for the most airflow short of a K&N i could get. I used a custom 1" thick rubber mount in order to get the vacum line between the carb and the filter, ive seen guys post this technique before. stock carb, with dynojets,full pipe system, Anyway ive tried running everything from 195 -210 DJ's, the problem is they dont make a 205 witch is what i think i need, but even with the 210 it seems to run rich but constantly the spark plugs stays whitish. Anway the best i can get it to run it runs well but at WOT seems to cut out a small amount and i have the RWR cdi so its not the rev limiter? I have a couple general questions about how the stock carb works, it must work off vacum? there is not a direct link between the slide and the cable, but ive run it with the vacum line off before and it worked, so im confused? Anway i think i may have to either go with a dial a jet setup or go with an aftermarket carb. What is the best carb you guys recomend for the $$, i will run a carb mount foam filter and i have a yosh pipe and graydon header, i will not be doing any other engine mods... would the Mikuni TM45mm flat slide carb kit offered by Ron Wood Racing be the best in this aplication>
thanks for the help guys
Jetjock16

 

You should check out Buttfungus's website. There is alot of jetting and mod info on there. Do a search under "jetting/mods data".

 

i know with the woods pipe and k@n i run a 170 main jet and it runs great, other than that hightower seems to mnow a lot about jetting,pm him

 

Not sure of your elevation or humidity, but those sound fat. Not that its much help, but my buddy got a 190, 195 with his dynoject kit last week. He settled for a 190 (3-4 clip position) He has the stock exhaust, with the aluminum 2.25" opening mod cap from MK site, plus the K&N filter kit. Ran great at Dumont.

jbt

 

jetjock,

How are you testing your jetting? Have you checked all of the different 'circuits' (top end, mid, low end, idle, etc) individually also? I have heard reading the plugs on a DS wont always tell you much, you should also check the suit buildup at the end of your muffler.

When you went to the direct mount filter, was that the ONLY change you made? Perhaps something else is giving you trouble? You could also try covering up part of your filter with tape to see if you get any different results - perhaps too much air flow for your current modifications?

Also a 190 Mikuni would be a 202.7 Dynojet, that would be a little closer to what you believe you may need.

 

jetjock,

The vacum holes that open the slider are in the bottom of the slider. The vacum is actually presented within the air pathway and its strength passes through the slider holes to create a suction on top of the slider that pulls slider open. I drilled my slider holes to help it get more vacum to the top of the slider and open faster. I'm not sure about what the external vacum line does. I just assumed it was a balance line.

The cutting out almost sounds like fuel starvation......

jbt

 

Slowride, that is some good technical stuff, thats what im looking for, Yes the cut out at WOT does feel like fuel starvation to me. I want to know more about how the vacume works, So the large vacume line on top i have routed between the filter and the carb, but the two smaller lines i have just run to a seperate little filter, is that part of the problem? Stock those small two lines were in the snorkle, so there would have been some vacume, should i re-route them to be in the vacume between the filter and the carb?
thanks for the help!
Jetjock16

 

The two smaller lines that come off the carb like ears can just be left alone. They are simply breathers. They shouldn't be drawing any vac. The big clear tub off of the carb will draw a vac, and should be filtered if at all possible. I put a small K&N on mine, actually RWR sells them for just that reason. I have mine road-mapped up towards that front of the machine and it comes out just on top of the right side of the radiator. The K&N is visable if you look between the plastic and the radiator from the top. If your running the vent tubs back to a path of air travel that would actually be creating a vac in those tubes. That could be bad.

Some one on this form published a table that gave jet equivalents for Mikuni vs DynoJet. Do a search, it may yeild something.

Good luck

 

Jet as rich as you will ever need, as cold and as low as you will go then get an ATTAC from Holtzman Engineering. Never worry again!!!

 

I agree with BigDaddy on the vaccum lines. I put a generic k&n filter on the big clear one and it seems to work fine. I bought the filter from Autozone for like 7 bucks and zip tied it to the frame. Hope this works. I also did the same for the breather and have not had any problems with oil comming out of it.