Back firing problems on 86 700.

My bike backfires and I was hoping you guys could help me out as to why. It idles just fine, but when turn the throttlle and hold it around 3000 rpm, it backfires. Actually, it sounds more like it's misfiring.

The bike runs fine, and I don't really notice a problem as I'm riding. It only seems to be noticable when it's parked and I hold the rev steady at or above 3000 rpm.

I changed the plugs and it is still doing it. I was thinking it is the timming, carbs are out of sync or bad spark plug cables.

Thanks.

 

Probably none of the above.....

Timing never goes off unless cams have been removed; maybe...


....try cleaning carbs; plug wires are good for at least 150,000 miles unless rodents have been nibbling.

If you want to experiment you could try backing out each mixture screw a bit and see if problem disappears.

 

Yeah, if I remember right I think backfiring means an overrich condition.
Squirrel has the right idea, adjust your mixture screw and check your air filter, you did not mention if you checked that or not.

 

I replaced the air filter and it's still doing it. I will try and play around with the carbs as you recommend. Hopefully that will do the trick.

Again...it only seems to do it as the bike is sitting still and I rev it at 3K or higher and hold it for a few seconds.

It's probably also doing it as I am riding, but don't really notice it.

Thanks.

 

Probably doesn't do it when you're riding, as the engine is under load. Mine pops a little on deceleration; but I can live with that. I have a Yosh full system and K&N filter. Any similar mods on yours?