I did the Harley Dyna swap and rejetted 150 main 52.5 pilot air mixture 2 turns out get this orange flaming on decel header checked no leaks does have a slight leak at the connection not too bad used tin can and heavy duty t clamp any ideas on what's causing it also small puff of black smoke when revving engine

Yeah I have the raptor petcock the pilot is stock I only changed the main jet my elevation here in ky is 600' here is a video of it

https://youtu.be/tt4t4dcpddI

Where does the orange flame come from....out the exhaust?

If you have a 47.5 pilot...most likely a 50 or 52.5 pilot will help.

Air screws set at "2 turns out" is the way you begin to tune your bike, you then need to actually adjust your mixture screw....it is a living breathing thing and the setting needs to be dialed in for each bike.  When you are doing the adjustment the bike needs to be fully warmed up, and if the smoothest engine speed is more than 2.5 turns out you need a larger pilot jet.....and if you can turn your mixture screw all the way in and the motor isn't starting to act up...you need a smaller pilot jet.

https://www.youtube.com/watch?v=zm5mB3R8Ucw

https://www.youtube.com/watch?v=YxpQjDQzX7g


Also.....the Savage is a bit primitive in design and it needs more love and attention than a modern fuel injected computer controlled motorcycle.  You need to learn how to do what the computer does for you on the fuel injected bike.  When you are shifting or slowing down - don't just chop the throttle and let it close completely.  When you hear the popping and banging while slowing down....just roll on a tiny amount of throttle until the noise stops.  Don't add a lot of throttle....you can add a little bit and reduce the noise with making the bike accelerate.  You may need a bit more brake as you could be doing less compression braking.  Same thing when shifting - don't close the throttle all the way....leave it open about 1/16 or 1/8th turn as you pull in the clutch.

The popping and backfiring is a result of the mixture going really lean when you close the throttle.  The slide drops and closes off the main jet - so the only fuel that can flow through the carb is coming out the pilot jet circuit....and that just isn't enough fuel for an engine that is turning much faster than idle speed.  So the really lean fuel mixture can't get ignited by the spark plug - but it does ignite in the hot exhaust system and creates the "bang" and yellow flame out the tail pipe.  (The stock muffler is very good at masking these events, and when you put on a more free flowing muffler - the popping and banging becomes far more noticeable.

I'd drop down to a #50 pilot... that flame and puff of black smoke is unspent fuel firing off in the pipe...

It sounds pretty nice with the new muffy...

..you might also check your air filter... clogged air filter will make you overly rich too...

the white spacer mod will richen it in transition and and part throttle
If your bike surges during low RPM low speed riding it needs the white spacer mod

Well I did the white spacer mod checked for exhaust leaks still getting a lot of backfiring on decel I checked the spark plug last night it was a tanish color not black at all like I thought it would be can't figure out if I'm too lean or too rich still have stock pilot jet don't know if I should go up or down

Talked to a buddy of mine that works for Suzuki he said to take the decel valve off and cut 10 mm of the spring off and that usuall corrects the problem he said Suzuki techs came down and done some training with him and they told him that usually correct the problem so he said he does it on all s40s that come in for carb problems so I tried it today sure enough really cut down on the backfiring issue actually made it run a little better now put about 40 miles on it today I could really tell a difference

wcemt83 wrote on 03/11/16 at 16:11:07:


Sounds iffy. I don't think I'll trust junk science and hearsay.

The Transient Enrichment valve spring and cutting have been "iffy". Some folks have luck....others don't,  One fellow listed a automotive carb spring for a accelerator pump that was supposed to be a bit softer spring and work better.