Marky, I had a similar problem with my carb bogging out over whoops, I took it back in and the dealer adjusted the floatbowl and that solved the problem.

 

Marky,

When at speed and going over rough terrain:

If motor runs lean and cuts out - float too low

If motor runs rich(dark exhaust) and fuel comes out vent tubes - float high

I believe the change to float bowl height was changed on 2001 models and
a service bulletin sent to dealers if 2000 had problems.

 

sand45,

Great - I like facts, not label reading.
The needle if thinner and longer which results in more fuel flow at bottom end. This helps bottom response till volumetric flow increases.

DSjockey - Thanks for your data verifying that reduced back pressure results in increased volumetric flow thru motor. This again enhances signal strength that increases bottom end response.

Lets pretend that I have purchased the jet kit and a new performance exhaust system. I go to an organized 300' drag event. I am against a raptor and he gets me by a quad length in first gear, and even though I am gaining on him, he is first to the finish line.
I have two choices - (1) Change the front sprocket to a smaller size.
(2) Enhance throttle response
Drag race rule - To stay in stock class you must use stock carb.
I only go to organized drags a few times a year and most of my riding is high speed trails. I do not want to change gearing since it is perfect for my riding and now I must continue to figure out how in enhance this carb.

 

Oldmanracing,
Good luck on sorting out how to get more power out of the stock carb[I mean that honestly, not sarcasticly]. In other forms of racing, with a rule of stock carbs, I've seen folks "massage" the carb with a die grinder for more flow, but it's not easy to make run right.

You seem determined to work on the carb, even if thats not the best place to concentrate on. It only takes 20 minutes [tops] to change a countershaft sprocket and they are only $35. You could easily change for the races, and change back for you trail riding. Keep in mind that you are going against Raptors that come with a 13/40 gear set[correct me if I'm wrong, I might be], compaired to your stock 16/40 gearing. Yes, there final reduction in the tranny is different, but not that much. Raptor motors just spin higher RPM. Temporarily changing your sprocket might give you the edge your looking for, with a lot less hassle than searching for more from the stock carb.

 

Knutz,
In the real world you bet I will be changing the sprocket. But lets say that I am in the last race for the win. My final opponent is on a DS with all the same features as mine. What do I do now. I do not believe that luck should be your final reason why I won the race.

As an overview:
(1) Has anyone changed the diaphram spring? Where did you purchase it and how did it help?

(2) Has anyone bored the carb oversize? How much? Were you able to purchase a larger butterfly valve to match new bore and where?

(3) Has anyone found an aftermarket cdi/rev limiter with a real performance curve that would enhance this stock carb?

 

3TV,
Back here in Wisconsin most of the drag strips are on clay soiled tracks.
We have to overgear to get out of the hole and then short shift to take advantage of the motor torque. We have too much traction and if you wheelie you loose. Some guys put on tires with very little bite, but as track conditions change thru-out the day this again comes back to haunt you. When I see you guys out west roosting the sand I envy you. We have a few areas with alittle sand but usally in a small area(old gravel pit).

 

Oldmanracing,

I wouldn't mind checking out your racing the next time I come back there. I was born and raised not all that far from you. A small town called Hartford. Maybe one of these times I'll bring mine back when I come visit my brother, is there a modified class I can run in?

 

Oldmanracing......Hey im sorry i did not get dyno chart for you!! Just trying to help. oh well!!

 

sand45,
Let me apologize. In my profession, as a quality assurance manager, I spend most of my job on continuous improvement. Getting folks to brainstorm ideals and collect data. I,in trying to get data sometimes get alittle pushy. The most important element of brainstorming is getting people to share and you have been doing that willingly. So again I apologize and please keep sharing your input.

Knutz,
Thanks also for sharing and to openly admit that you were once a cheesehead. Hartford is only 24 miles from me - what a small world.

Please look at this site and you will see many quads having too much traction. Classes and rules that are used here.
http://www.monkeybuttatv.com/

 

I guess the only class I could run in legally would be class 20. 700+cc and nitrous is allowed, I think I might have some trouble in that class. I don't run juice, and I'm thinking that I would see a bunch of motorcycle engines. The only other bike I would have a chance with would be a 720 Raptor, if it's not on the juice.

Born and bred a cheese head, and always will be. I'm just hoping the Pack can do me proud agaist the Bears today.