Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[AndyB1976]

Hi All!
Hope everyone is safe and well?
I have noticed that my 1800Ci Twin cam has started to backfire when turning over at ignition which comes out of the air cleaner.
Has anyone else had a similar issue??

Thanks

[grc]

The 2008 came with the original design compensator first used on 2007 Twin Cams, and it was not strong enough for the 110 cubic inch engine.  Many people had starting issues including backfire and kickback, as well as knocking on shutdown.  Replacement with the latest version of the Screamin' Eagle compensator helped solve those issues.  Harley finally made it standard on 110's for the 2010 model year.  Also check to make sure the primary chain tensioner is working properly, and the automatic compression releases are working.

Jerry

[Joel]

A weak battery can also be something to cause this condition do to a slower cranking RPM.

[ultra13]

I have experienced this also on my 13' Ultra. It's only periodically. This winter I replaced the chain tensioner because the chain was too tight....Little did I know you can take the tensioner out and reset it....Was hoping that the occasional backfiring and kickback would stop. Everything looked good on the compensator so I didn't worry about that. After five or six rides it backfired for the first time last weekend. Going to keep testing it over the next couple of weeks.

[AndyB1976]

Thanks Guys.
I do suspect that the battery is weak, but as a matter of course I was planning on changing the compensator.

[JKM]

on my 2008, when my compensator was getting weak, it would have similar issues.  Same with when battery was getting weak.
If you have not done the compensator, then definitely likely needed in any event.

[fastfreddy]

my last bike (13 SERG)  ate compensators and every time it was ready to be replaced it would sneeze and back fire thru the intake.... 4 comps in 50k miles

[HD Street Performance]

I recondition cylinder heads, as many know. I can tell you without hesitation that many of the 103 and 110 heads I receive to work on, if they have accumulated excessive carbon, have plugged ACR passages. I use a long special drill to get the passage clear with the ACRs out. The ACRs do not function if these passages are plugged.

[AndyB1976]

Thanks for the info.
I am having my Heads worked on over winter this year, I have just upgraded my cams etc so hopefully that will help.

[johnsachs]

I recondition cylinder heads, as many know. I can tell you without hesitation that many of the 103 and 110 heads I receive to work on, if they have accumulated excessive carbon, have plugged ACR passages. I use a long special drill to get the passage clear with the ACRs out. The ACRs do not function if these passages are plugged.

This is what I've been doing/using since 08, when I had a set of heads come in with both manual and factory compression releases. The company I use for pest control uses a sign, mounted with .155" wire ( this will be the largest diameter hardened wire you can use). I cut a piece approx. 8" long, grind a point on 1 end, insert in the release passage in the exhaust port. You may have to tap it in on some badly clogged passages. Go easy, and use a little brake cleaner if needed. Don't forget to remove the compression release before you start.
John

[ultra13]

Good stuff here. I am still investigating my problem. So to the gentleman that work on the 110 heads...I take it you have to have the heads off to do the fix (cleaning of the ports) due to carbon buildup? How does this happen with normal riding and service? Can it eventually clear up on it's own? I am not saying that by replacing my tensioner has fixed my problem but when I rode yesterday it started (at 4 stops) easier than it ever has.

[johnsachs]

Good stuff here. I am still investigating my problem. So to the gentleman that work on the 110 heads...I take it you have to have the heads off to do the fix (cleaning of the ports) due to carbon buildup? How does this happen with normal riding and service? Can it eventually clear up on it's own? I am not saying that by replacing my tensioner has fixed my problem but when I rode yesterday it started (at 4 stops) easier than it ever has.

To clean or unplug the compression relief ports in the exhaust port. You only need to remove the compression release and obviously the exhaust system. If the passages are plugged or close to being plugged, they won't fix themselves. If you have the heads off, don't forget to always check and clean the passages. If you have a bad tune, or an oil burner, they will accelerate clogging.
John

[HD Street Performance]

This could be done on the bike, tank off, pipe off,
as a maintenance item.

[ultra13]

If they are plugged wouldn't it backfire frequently?  First and up of the day and through out the day?  Mine might do it once every 2 months ….Lets say in 25-30 starts.

[HD Street Performance]

All it can do is help and take a little time to check. If it were mine, depending on the miles and history, I would be looking in the primary first. If it has the first version compensator that would go regardless of whether it was worn or not. The 2007-2008 compensators were garbage, first version. You can take a piece of wire, say between 6 and 9ga solid copper pointed, to see if the ACR port is plugged with the pipe off. If it is plugged pull the tank and ACR valves and clean the passages out. See what John described