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Carb modification question

Paladin

Paladin

Member
Got the carb off and the previous owner never rejetted for exhaust or air cleaner. The printout I have mentions replacing the main jet with a #170 and the idle jet with a #45, which I planned to do. It also mentions drilling the vacuum orifice to 1/8 and putting a washer under the jet needle. Anybody else made these mods to a carb?
I've read some other stuff that just says just replace the jets. Don't mind doing the drilling and washer but though that might only apply to the big motor, not Sportys.
Anybody else removed the evaporative emissions hoses and canister under the bike?
Thanks for any info.

Moderators, I posted this in the Sportster section but realized this was maybe a better place to post. Sorry.
 
Paladin said:
Got the carb off and the previous owner never rejetted for exhaust or air cleaner. The printout I have mentions replacing the main jet with a #170 and the idle jet with a #45, which I planned to do. It also mentions drilling the vacuum orifice to 1/8 and putting a washer under the jet needle. Anybody else made these mods to a carb?
I've read some other stuff that just says just replace the jets. Don't mind doing the drilling and washer but though that might only apply to the big motor, not Sportys.
Anybody else removed the evaporative emissions hoses and canister under the bike?
Thanks for any info.

Moderators, I posted this in the Sportster section but realized this was maybe a better place to post. Sorry.
Click to expand...

One more second on the DO NOT DRILL THE 1/8" HOLE IN THE SLIDE. I have a '91 1340 EVO, and have made that mistake myself. Bigger jets and the washer on the needle should give you a great ride. If you drill the slide and don't like it, you will have to replace the slide. If you don't like the rejetting results for some reason (can't imagine that but maybe), you can always swap back out, or try different ones.

TQ
 
Ended up going with a #48 slow jet and a #180 main- no other mods. Bike runs real nice- lots more mid range torque, NO MORE COUGH AT OFF IDLE- ya! Bike is an 883 at sea level.Thanks for the advice guys.
 
Running drag pipes with light baffles and a K+N air filter. Idle screw is about 2 1/2 turns out, RPM at about 900-950. The bike was coughing at throttle tip in pretty bad before carb rejet. OEM Plugs were really clean (too clean), no deposits at 13,700 miles. The carb screws were tight and the plug was still in the idle mixture screw. No evidence that the carb was ever taken apart. It had a #45 slow and a #170 main in it when it was built- possibly a California thing?
Anyway, just went up one step with both jets, makes a big difference. No cough, better low end grunt.
Maybe the previous owner bored the bike to 1200- I don't know cause I never met him.
 
The drags will upset things a bit too.
It's also possible that the jetting was done without the removal of the idle mixture plug being there was a #45 in there which is bigger than stock.
If you have the factory manual, on the first page of the carb section they will give you the stock jetting for your carb.
 
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