If you are going work on the stock carb this might help CV carb mods

 

Gashog, thanks for recomending those books, the last performance book I read was Smokey Yunicks Power secrets.

 

BillDS650, thanks, I just found that the other day using Google. The thing I picked up on is they write about opening only one hole up in the carb slide where the Mikuni has two air bleeds.

 

Although it works sometimes, I have found that racing against a buddy etc. is the worst possible way to tell if you are making more horsepower. When I find as little as 2HP on the dyno I have to make suspension changes to put that power to the ground. Most of the time when I get to the track with more power I will be running the same et's as last time or a little slower. Then the process of tire pressure, wheelie bar heighth, shock compression and rebound etc. has to start all over again.

mystereid, why do you think its odd to make gains across the board with a bolt on. I personally would not own a product unless it made gains from idle to max rpm.

I run the air box with a stock carb only. I have never been beat by someone running a stock carb with out the air box. I agree that the air box restricts flow but the vacuum operated slide will not open with out it, period. I could put another 40hrs of dyno testing into it and probably get more power with the box removed but the tracks I race at require that it be on, thats why I tested it that way. My results make impressive power with a stock carb and I have shared those results for one reason; people are wasting their hard earned money on things that dont work. I think I proved at Aledo that a stock bike tuned right is BRUTALLY FAST.


MrHorsepower

 

Now come on, I have personally seen DS's wearing stock carb w/ carb mount filter in motion, and have also been beaten by them. I'm not saying carb mount is better mind you, like i said before I haven't dicked with it, but it does work just fine.

 

When I say it will not open I'm speaking in a performance manner. In other words it will not open 100% and stay open at full throttle. It fluctuates at high rpm because of vacuum signal loss and reversion. Anyone that has ever been on the dyno could not overlook this as the dyno sheet has severe spikes in the power curve.



MrHorsepower

 

I see, my bad, I also overlooked your very next sentence after that one which would've explained too [img]i/expressions/face-icon-small-confused.gif[/img]

 

Cool !!

 

MisterHP, I agree that the fluttering of the vacuum slide is the CV carbs biggest problem. What measures did you try to limit this? Did you try routing the vent to into the filter? How about restricting the vent orafice. Did you try the slide bleed hole drill and spring tricks? If you dyno tested every option then there is no reason for me to procede.
Side by side racing is the best I can do without a dyno. Racing I guy I've know for 25 years and raced a thousand times, with an identical bike works a whole lot better than trying a change out in my back yard.
Uphill sand drags seem pretty forgiving for chassis set up. Beach racing on flat sand also works pretty well because after the hole shot you can tell easily if the guy next to you is gaining or losing.

 

i kind of agree with mystereid, the sand decides who is faster pretty quick. but if i could i'd get a dyno for the garage, but i just can't bring myself to get rid of the gym set up that i paid to much for.