BackFiring Help

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Nov 6, 2009 | 04:33 AM

1979Sportster

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2nd Gear

Joined: Sep 2009

Posts: 6

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BackFiring Help

Hello all. I have a 1979 Ironhead and recently had to replace the sprocket cover gasket. While in there, with the help of IronMick, i wound up having to get the timing correct on all the gears. Now that it is back and running, it starts but backfired constantly, and when I removed the air filter from carb there was fire shooting out of the carb. (looks great...but I assume its bad)

Any help would be greatly appreciated! I am hoping to not have to start from scratch again but maybe thats the only way?

Nov 7, 2009 | 12:01 PM

seventyiron

Intermediate

Joined: Sep 2009

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From: Texas!

Are Ya certain all the marks on the cams are lined up perfectly? if so,sounds like the timing is off to me..

Nov 7, 2009 | 05:47 PM

IronMick

Stellar HDF Member

Joined: Jun 2008

Posts: 3,179

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From: London, ON Canada

Quote:

Originally Posted by seventyiron

Are Ya certain all the marks on the cams are lined up perfectly? if so,sounds like the timing is off to me..

+1 on this. These are the two things that would be changed by removing the cam cover, the cam timing and the ignition timing.

Did you perhaps take a pic of the cams with the marks lined up?

When you replaced the timer plate how did you orient it? Did you follow a static timing procedure? Did you check the ignition timing with a timeing light?

Nov 8, 2009 | 11:26 AM

1979Sportster

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2nd Gear

Joined: Sep 2009

Posts: 6

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I did not take a picture (unfortunately) but am pretty sure I know what it is. You are right again! The problem I had was when I was placing the Front exhaust cam gear, I was not able to get it to the proper placement (10:00) mainly because the Tappet was stopping it from rotating far enough. I think I may have gotten it to about 8:00, so this is probably my problem? When I disassemble it again, how do I get the Tappet to move up far enough in order to get the Gear in its proper location?
Thanks again for all of your help!!

Nov 8, 2009 | 02:12 PM

piniongear

Stellar HDF Member

Joined: Feb 2006

Posts: 3,035

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From: Houston Texas

Quote:

Originally Posted by 1979Sportster

If you have to move the tappet base up to get the cam to rotate....then that is what you must do. Raise up the base!
Never install the cams with the marks mis-aligned. You are courting disaster doing that.
pg

Nov 8, 2009 | 06:50 PM

1979Sportster

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2nd Gear

Joined: Sep 2009

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Thank you thank you! I will do so. I tried to push it up far enough to rotate the cam but wasnt able to get it to raise any further. Is there something, or some kind of trick I am missing?
(sorry for my ignorance...first time bike owner)

Nov 8, 2009 | 07:19 PM

piniongear

Stellar HDF Member

Joined: Feb 2006

Posts: 3,035

Likes: 17

From: Houston Texas

Quote:

Originally Posted by 1979Sportster

Here is an exploded view of the engine. You will have to remove bolt (#1) and raise the base (#3).
The base has one O ring around it (#5).

You may have to use a tool that is shown in Fig. 3-26 of the next pic.
This tool can be made at home, as I have made it before myself. Just look at the pic. The threaded bolt screws down into the tappet itself, raising the base up. Just raise it far enough to get the cam installed, then bump it back down with a soft hammer (rubber or plastic mallet).

Read carefully under Valve Tappets and Guides.
Note that it may be necessary to raise the cylinder to raise this front exhaust tappet base.