01-27-2007, 08:33 PM
i have had the carbs of my sled this year to clean them put them back on and now i have a problem at wide open throttle ONLY at 7/8 throttle its fine but as soon as i go wide open the sled bogs bad but stays at a constant rpm if i let off a little its fine i didnt change the jets or anything just cleaned them i need some feedback its really bothering me
01-27-2007, 09:25 PM
Is it possible the sled is overreving? We had that once on a sled, the ramps in the secondary were worn out causing the sled not to full shift out, really felt like it was missing but actually was just winding too high.
01-30-2007, 12:37 AM
I have rebuilt/cleaned/tuned a lot of mikuni vm34ss carbs in my day. There are a few very important things that must be done. To do job right, you must have a carb airflow measuring, balancing, tuning tool. I forget the real name. When you put carbs back in sled, first set the air screw adjustment to factory spec, usually found on sticker on hood, then install carbs. This not done right can really mess with you. Next hook up choke cables. Check to make sure you have about 1/4 inch free play in choke cable at the choke lever. Next install carb pistons, throttle cables, air balancer tubes. Make sure top caps are tight and idle screws are almost all the way out. Pull throttle, let snap back, to check operation. Now look at all carb pistons. Loosen all throttle cables so all pistons are at dead bottom. Tension all throttle cables separately just until each cable just lifts the carb piston up a blond hair. Snap throttle. Now when engaging throttle from dead bottom make sure all carb pistons lift at exactly the same time. This matches all throttle cable lengths. Now turn all idle screws till they lift each piston up a blond hair. Now turn each idle screw in just a bit more, like a 1/4 turn, making sure to be exact. Look at carb pistons, engage throttle and make sure all carb pistons lift at exact same time. Adj idle screws to make the same. Start sled. adjust all idle screws equally to get to factory spec idle rpm. Now use air guage to match exactly all idle air flows. Adj idle screws to do this. Once this is done, rev up to about 3000 to 3500 rpm. Use air guage and check air flow on each carb. Adj throttle cables to make all the airflows the same and tighten down lock nut. Recheck idle rpm and airflow and repeat previous steps. Unless clutches are worn, this should fix your problem.