Whoa, did I hear mention of some carb adjustment to eliminate some shifting? that is the only draw back I can see with my 2001 400 manual. Lots of shifting. If you guys can tell me the best direction to go I would appreciate it. Should I try the screw turning first and if I have to buy a new needle which one should I get? thanks All

tbstone

 

Hey Cowboy no need for forgiveness. My bike is a 2000 model year, I bought the service manual with the bike and the carb adjustment seems to be the same for the 500. The Titans are 25".And yes I did notice better throttle response. I callled the dealer after doing the adjustment as I was a little concerned about running to lean. He said keep an eye on the color of the spark plug and watch out for white or gray,which would indicate a too lean condition. I will double check the manual later tonight as I seem to remember the setting being slightly different for the 500. Boner made a comment regarding the different carb used on the 2000 Auto's and the 2001 machines so I am not clear as to how to know for sure which carb you have. The adjustment screw on mine is on the bottom of the carb at the front. The screw is recessed about 1/2" in the body so a mirror and a flashlight might help locate it.As far as the fuel mileage goes I think it improved some but nothing to write home about. The biggest thing I noticed was in 5th gear running up a hill, before the adjustment the bike would always slow down and cause me to drop a down a gear. The other thing that changed was the response from a dead stop when pushing the throttle to the wide open position. Again before tha adjustment there would be an every so slight delay in takeoff, the didn't bog but it did not grab the revs right away either, all that has changed. After I did the adjustment, it was like having a new bike.

Cheers Jim

 

OK Cowboy heres the skinny on the carb info. Both the 400 and 500 use a BST34 carb according to the 2000 AC service manual. Which I think is a Mikuni carb. As far as the pilot adjustment screw is concerned the correct setting is 2 turns plus or minus 1/8 turn or from 1-7/8th turns to 2-1/8th turns.I hope you get the same results asI did.

Cheers Jim

 

Thats the biggest thing the AC 500 has over the 400 IMO. I hardly ever have to shift on my cat. I can stay in 5th gear all they way to 10-15 mph and never have to shift untill I drop below that. And thats why out it straining at all.

JKB,

The BST34 is a Mukuni, but the AUTO and 2001 models use a Keihin.

 

 

I followed jkb's advice on the carb. adjustment because I to were lacking the power when in 5th gear and climbing, but after the adjustment it is indeed like a whole new machine and yes you summed it up when you said it was wild. I would advise any 400 owner to make this adjustment if they are suffering from lack of high end power when in 5th.
Not only do you notice the power difference in high gear situations, but you just have some much more throttle responce.
Your information was very helpful and hit the nail on the head.
Thanks jkb