1984 gs 1150 vance & hines pipe popping

[Guest]

I just recently installed a Vance & Hines Super sport Full System 14301 header on my 1984 GS 1150, I never changed the factory jetting 122.5 mains and the air box and filter are origanal.The bike runs fantastic up to the redline and beyond (allot better than the factory pipes), but when you let off there is a lot of popping at the muffler.It also has an intermittent pop at a constant highway speed The plugs do have a little bit of white powder on them which I know indicates it is running a little hot.

I was wondering if this is normal with this header pipe, I don’t want to rejet unless I absolutely have too. Thanks for any information .Joe

[Turtleface]

Re-jetting with a new pipe is pretty much mandatory. PO had installed V&H pipe on my 1100, cautioned me that it ran a little hot. Heat problems disappeared after a re-jet.

[trevor]

Re-jetting with a new pipe is pretty much mandatory. PO had installed V&H pipe on my 1100, cautioned me that it ran a little hot. Heat problems disappeared after a re-jet.

What he said.

[cableguy]

You're running lean which means hot, and no matter what you do short of re jetting the popping will continue. If your headers aren't blue yet they will be quickly. The Dynojet kit is plug and play, and you won't believe the difference. Make sure your valves are adjusted and carbs synched!!!!!!

[JTGS850GL]

Exhaust air leak would be my guess. My bike does the same thing with rejetted carbs and a V&H 4into1 exhaust. Sounds really wicked when you let off the gas. Lots of popping and growling. On mine it's a known issue with a crack in the collector pipe right where the muffler joins the collector. When you let off the gas you create a vacuum within the exhaust pipes. Any air entering the exhaust will ignite the unburned fuel. Check all your exhaust bolts and look for any loose connections or cracks between the head and the muffler.

[trevor]

Exhaust air leak would be my guess. My bike does the same thing with rejetted carbs and a V&H 4into1 exhaust. Sounds really wicked when you let off the gas. Lots of popping and growling. On mine it's a known issue with a crack in the collector pipe right where the muffler joins the collector. When you let off the gas you create a vacuum within the exhaust pipes. Any air entering the exhaust will ignite the unburned fuel. Check all your exhaust bolts and look for any loose connections or cracks between the head and the muffler.

He still needs to re-jet for the pipe. You said yours are rejetted, his aren't, they are stock.

[JTGS850GL]

The jetting will help driveability, but the popping on deceleration is most likely an exhaust leak.

[trevor]

The jetting will help driveability, but the popping on deceleration is most likely an exhaust leak.

My 1100 popped on decel too after putting on a V&H 4-1, until I jetted properly, then no more popping. Just my experience.

[trippivot]

de accelleration and scavenging make noise.

De-cell popping can be reduced with a larger PILOT jet in carbs without a decell circuit -- to a point you can make it quieter - some carbs have a de-cell enrichener diaphragm keihin cv's especially... they give the bike more gas when the vacuum rises to a specific point....

however a 4-1 has a little thing called advanced scavenging due to sound waves creating negative air pressure..

ok so mild and moderate popping is just a thing that happens when some super heated scorched nitrogen re-ignites O2 in the little amount of fresh air in the megaphone collector,,, no mechanical damage will result -- it bothers some riders but is a indicator you are right in the stoich. range. getting it all from every drop of gasoline.

now if you have huge explosions on de cell get some new float needles.