STILL BAffeled Part 2

Energy One

rhinoevans

Active Member
Still Baffeled

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If some of you remember an earlier post on my 2002 Pitbul. Very poor DYNO (70 HP) and a very small main jet (62) to get the right a/f ratio. Started some troubleshooting.

1. Sent carb to xXx and had a complete upgrade kit and Bob checked it out and said the carb was good, except for some valve blowby on the carb. He did fix a cracked a/f mixture screw problem. Obviously someone had over tightened it. When I got the bike it had a 70 main and was still running RICH.

2. Compression and leak down on the motor last week. All numbers good. I was convinced it was a valve problem despite the fact that the bike run great cept for the loss of 20-30 ponies.

3. Installing a 600 as we speak (at the dealer). Should know more later on that. My mechanic thinks it all about the cam, so that is why we went for the 600. However, I still find it hard to believe that what ever cam is in the bike will call for a 62 main jet. I also think that the small main explains the loss of HP.

4. Pull the V&H exhaust. All looked good. Did look black and sooty from the rich condition.

5. Bike runs good, so timmng is OK.


PART TWO: Pulled the cam to put in the 600. Guess what we found. It already had a 600!!!!!! Pulling the pipes tomorrow and dyno with different pipes. Only thing left to check.
 

rhinoevans

Active Member
Had it dynoed to tweek the carb adjustment and fine tune the A/F ratio. Also bike was running way rich with 70 main. DYNO showed a 62 main as the jet to make the A/F what it should be.


Carb reworked 2 weeks ago by xXx. Bob said it was good.

Incompetent guy running the DYNO would not explain why the main jet is so small. Also, when the carb came back fro xXx, Bob tuned it to his test motor and the main was a 74. Back on my bike, I could tell that with the 74 main, it was too much fuel at that rpm when the main jet kicked in.

Just can not figure why the HP is so low and the main jet so small!!!
 
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