New pips Do I need to rejet the carbs on my Harley low rider if I install new SLIP ON pipes?? If so should I pay to have it done with a dyno or do it myself? Thanks to those motorcycle enthusiasts with answers for me!

Removing the baffles will lean out the mixture, so either rejetting the carb, or reprogramming the ECM or a "piggy-back" unit installed will be needed.

Actually, open "straight" pipes are the worse for performance, as some back pressure is needed.

Also, to help performance with a "free flowing" exhaust, a more "free flowing" air cleaner would be needed.

no pe

1. vacuum leaks at the back side of the carb spigots or other vacuum lines off/broken. Remove the carbs and spigots from the head and clean with acetone/laquer thinner afterward sealing the spigots to the head with gasket maker/silicone rtv.
2. Carb idle and low speed jets may be plugged up and carbs need a correct cleaning.
3. Carbs need rejetting to match the after market mufflers. Take it to a shop with a motorcycle chassis dyno and they will be able to tune the after market pipes.

I have a 2007 Honda Shadow Sabre VT1100 and I also put after market pipes on it from Vance and Hines. I also have to keep it choked when first starting and sometimes even hold the throttle a bit while it warms up. The bike has two carburetors and the best solution I have found by lots of asking around of mechanics and bike folk is to get it rejetted through Dyno Jet. It is meant for bikes with after market exhausts and much less back pressure from the lack of those stiffling baffles in the stock pipes. I have also noticed the power loss in the middle torque range and backfiring because of the bike running in a lean condition. The Dyno Jet website is a good place to find the correct set and corresponding part number, but then I suggest finding a cheap place online so you avoid retail price :) Hope this helps. Oh, and don't forget to buy two kits...we have two carburators in our bikes.

That's hard to say. A motorcycle engine is finely tuned system. If you change one thing, that changes something else. It is possible that you may not have to change anything. Then again, you may have to rejet the carburetor. As they come from the factory, the carburetor is jetted very lean in order to meet EPA emissions standards. The free-flowing mufflers will probably make it run even leaner. Rejetting the carburetor is not very expensive but the labor to have it done could be. Just go to the next size slow speed jet and adjust the idle mixture screw. Those "DynoJet Kits" are a rip off.

Good Luck
Steve

It will kill the low end tq..you can do it itll be louder .. the air cleaner will allow the same air in ..if you would put on a freeer flowing a/c then jetting changes would be needed...

I would rejet the carbs. I would go one size up on the jets. That should clear up the problem.

decel pop is caused by a lot of things! if you have big pipes; ie:drag you need baffles to tune the exhaust wave; theoretically upon decel instead of exhausting you are actually allowing reversion- which allows exhaust to actually renter your engine and try to get compressed again; very bad for performance, etc big pipes are cool but need proper baffling and tunage to be useful; may be too lean possible fix w/ supertuner/ dyno runs; I like "lollipop" baffles you can make for under 5 bucks and tune as you need; thats what I run on my 95HP sporty; Have Rinehart true duals on my Road King and via ecm tuning you can really dial it in. F/I is great but you need to "pay to play" no quick fixes like in the carb days; really need a dyno or some sort of computer tuning capability; I recommend Super Tuner rather than the piggyback setups; more expensive at first but wont fry your ecm either. A good dealership will be able to tune it right the first time in under an hour...sorry for the lenghly reply but I see this question all the time...T

All anyone is doing at this point is guessing on the jet size. With all the work you've had done I would go ahead and pay for a dyno tune up.

just make sure you rejet the carb all bikes come from the factory on the lean side to meet epa standards etc. if you dont rejet you'll actually lose some power and have nasty backfires as well take the time to put a jet kit in i personally recommend dynojet easy to install and comes with suggestions for your application