Backfiring through carb
Seasoned HDF Member
Joined: May 2008
Posts: 21,221
Likes: 12,816
From: South Carolina
The slow return to idle is probably due to the cable. Some folks like to run the single cable system.
The Mikuni has a flat slide, and is prone to sticking.
When using a single cable, and the cable starts to bind (as they sometimes do before failing) you are stuck with a stuck throttle.
When running a dual cable, and the cable binds, all you have is a stiff throttle, so you will have some time to get the bike back to the garage.
What type intake do you have on the bike? Look at the intake manifold, if there are rubber manifolds bolted to the cylinder heads, you have the OEM setup that came on the bike.
The Mikuni has a flat slide, and is prone to sticking.
When using a single cable, and the cable starts to bind (as they sometimes do before failing) you are stuck with a stuck throttle.
When running a dual cable, and the cable binds, all you have is a stiff throttle, so you will have some time to get the bike back to the garage.
What type intake do you have on the bike? Look at the intake manifold, if there are rubber manifolds bolted to the cylinder heads, you have the OEM setup that came on the bike.
Last edited by Dan89FLSTC; Oct 19, 2013 at 08:47 PM.
Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
Usually the high idle/slow return is an intake leak, the popping is the same thing....if it was me I would replace the manifold to head seals, the manifold to the carb seal, check any vacuum pipes and put a #45 idle jet in.
Seasoned HDF Member
Joined: May 2008
Posts: 21,221
Likes: 12,816
From: South Carolina
I never could find any decent cables for the HS40, the only cables I could find were from Motion Pro, and they were pretty wimpy, and would only last a couple of years before they would start to fail.
Being that the OP`s bike is an `87, there`s a good chance that the carb is an HS40 (a great carb).
Road Warrior
Joined: Dec 2007
Posts: 1,286
Likes: 64
From: SoCal
If you need to replace cables, try Barnett.
I have always been happy with their stuff.
If you need help ordering the correct cable, call them and ask for help.
http://www.barnettclutches.com/
I have always been happy with their stuff.
If you need help ordering the correct cable, call them and ask for help.
http://www.barnettclutches.com/
Road Captain
Joined: Apr 2012
Posts: 628
Likes: 14
From: Sweden via Bisbee, Az.
I love it! I thought I was the only one that drank that... Seafoam and vodka Babbyy!!!
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Novice
Joined: Oct 2013
Posts: 16
Likes: 0
From: Indiana
Finally got around to replacing my intake seals. No more backfiring! Runs great! Still not settling back down to idle as quickly as I think it should, but definitely better. Cable replacement next on the list. Thanks again!
Road Master
Joined: Jan 2008
Posts: 1,187
Likes: 8
From: Montgomery, AL
Thanks for the update. My bike was slow to come down to idle, like the cable was sticking and it turned out to be the thumb screw under the throttle. Give it a little time to clean up after the intake seal leak.