backfire

[Torque818]

OK I am no mechanic and need some help here, back-fireing up through the carb is a product of poor carb synchronization/balance? can it be anything else? idles nice other than a "pop" back through carbs every 2-3 seconds. any help would be appreciated

 

[mwbill37841]

could also be crossed wires. to many backfires can blow the tops off your carb slides. don't ask how i know that...lol

 

[joedrum]

yes what bill said is highly likely ...if viewed from the set as rider ...the righ coil suppose to fire front cylinders ..the left coil fires the back cylinders ... so you know that ...if wires seem right ... take one plug wire off at a time and start or try to start ... till you find witch cylinder is causeing the backfires and don't run it much to find out ...is what id do first .. the post what you find out

 

[dan filipi]

Have you adjusted the valves?

I don't believe carb sync has anything to do with the typical pop back like your getting, mine does it real bad and I'm pretty sure the problem is all in the rear pickups and the coils getting a random or non-precise spark signal.

There are times it spits back less and times not at all. I haven't discovered any rhyme or reason for it but it does do it worst just off idle and engine cold.

 

[Torque818]

dan filipi » Thu Aug 29, 2013 6:41 am[/url]":26wcinyd]
Have you adjusted the valves?

I don't believe carb sync has anything to do with the typical pop back like your getting, mine does it real bad and I'm pretty sure the problem is all in the rear pickups and the coils getting a random or non-precise spark signal.

There are times it spits back less and times not at all. I haven't discovered any rhyme or reason for it but it does do it worst just off idle and engine cold.

Thanks Dan, I believe the rear pickups are a drop the motor out to inspect/replace procedure? My igniters have had the tar insulation melted off but are still working, could they be intermittently failing? the motor runs strong when "on the gas" but idle and steady cruise is when I get most of this issue.

 

[joedrum]

yes

 

[dan filipi]

Well I have a pair of good ignitors, I'll have 2 pair if the c5 ignition proves to be all I hope it will be.
If it is there ain't no way I'll ever go back to the stock ignition so I'll send you a good pair for shipping and a donation to the forum.

It may be a few weeks before I get the install done if you can hold out.

 

[Torque818]

Torque818 » Thu Aug 29, 2013 8:34 am[/url]":2qzls6hc]

dan filipi » Thu Aug 29, 2013 6:41 am[/url]":2qzls6hc]
Have you adjusted the valves?

I don't believe carb sync has anything to do with the typical pop back like your getting, mine does it real bad and I'm pretty sure the problem is all in the rear pickups and the coils getting a random or non-precise spark signal.

There are times it spits back less and times not at all. I haven't discovered any rhyme or reason for it but it does do it worst just off idle and engine cold.

Thanks Dan, I believe the rear pickups are a drop the motor out to inspect/replace procedure? My igniters have had the tar insulation melted off but are still working, could they be intermittently failing? the motor runs strong when "on the gas" but idle and steady cruise is when I get most of this issue.

And Yes I have the valves adjusted nicely, .004 intakes, .005 exhaust.

 

[slabghost]

No the rear ignition pickups do not involve removing the motor. Just the rear of the bike and fuel tank. It's not easy or fun but can be done. The 80 has both vacuum advance and mechanical advance. Trouble with either can cause backfire problems.

 

[dan filipi]

2 ignitors going out in the mail today.

 

[Torque818]

dan filipi » Fri Aug 30, 2013 6:26 am[/url]":1bs7lkbt]
2 ignitors going out in the mail today.

Thanks Dan! :thanks: :salute:

 

[C5Performance]

joedrum » Thu Aug 29, 2013 10:35 am[/url]":2vtgsgaz]
yes

+1!!

When the potting material starts to melt, that's bad. It could be a spark issue but listen to Dan, and verify your valves are adjusted.

Had this problem started over a long period of time or just a recent thing?

 

[Torque818]

C5Performance » Fri Aug 30, 2013 9:11 pm[/url]":g51ntn7w]

joedrum » Thu Aug 29, 2013 10:35 am[/url]":g51ntn7w]
yes

+1!!

When the potting material starts to melt, that's bad. It could be a spark issue but listen to Dan, and verify your valves are adjusted.

Had this problem started over a long period of time or just a recent thing?

Just bought bike used 3 mo. ago or so and got it running 2 mo. ago and have been fighting this and other issues (blown head gaskets, final drive gears Carbs clogged etc....). valves are spot on, .004 intakes, .005 exhaust.