Popping noise on decell and at idle.

[ricksbike]

Hello all,well i still have my strange noise on decell and at idle,I have checked valve adjustment,checked cam chain tensioners,spark plugs, compression balanced carbs,replaced both rear cylinder plug caps,checked carb operation and diaphrams,checked for airleaks,I have a little noise in my clutch and it`s starting to slip,so I`m going to replace that next,I`m wondering about air cut-off valves or coils,any help or comments would be greatly appreciated.

:confused:

[Venturous]

I know you said you check for air leaks... but my bike did this when I had worn/loose exhaust to engine gaskets. Could not feel it with my hand... but found it by taking a long grill lighter and moving alone the pipes with bike running. As soon as I got close to those gaskets... it was trying to suck the flame into engine. Tightened... pop went away.

[Vonwolf]

I have had that same popping at deceleration forever that sounds like an air leak in the exhaust, that lighter to the gasket's sounds like a good idea. Both my exhausts have a hole at the bottom right where the collectors are, but I think they were made that way for some reason. I'd be really interested if you figure it out, I haven't had any luck tracking mine down

[KenP]

I used to have a First Gen.....this is the procedure I found to work for me......

 

Pilot circuit (zero to 1/8 throttle)-

The mixture is lean if:

the bike surges while holding a steady throttle at about 4000 rpm in second gear.

there is excessive back-firing on closed-throttle overrun.

the throttle is lightly 'blipped' and the idle speed 'hangs up' before dropping to the set idle speed (set the idle to 1000 rpm to start).

Correction: turn the pilot screws OUT 1/2 turn or so. If the pilot screws end up turned out very much more than three and one half turns total (stock is about 2 1/2 turns), you should use larger pilot jets.

The mixture is rich if:

the plugs are excessively soot-ed up or fouled.

the throttle is lightly 'blipped' and the idle speed drops below the set idle speed before rising up to the set speed.

 

Correction: turn pilot screws IN 1/2 turn.

 

 

It could be float level too high, but seems like it wouldn't be all the way around. It could be a too cool spark plug (Yamaha recommends an "8" range plug, that is what I run). I'd say check the air cleaner and mixture, and see what happens. And a LOT of troubles have been found to be air leaks at the rubber connection of the lower carb manifold or age cracks on the sync blocking nipples below each carb. The

lower half of the lower rubber carb manifolds have a metal insert for mount integrity and a lot of our bikes develop cracks near the bottom on the outside... this is almost always cosmetic and NOT a leak source, if it's a bother, use some black RTV and smear it in the crack and wipe off excess.

[videoarizona]

Sure sounds like an air leak somewhere....I like the exhaust idea as well....

 

YICS?

Edited April 24, 2015 by videoarizona

[videoarizona]

Oh for clutch info...try here....

 

http://www.venturerider.org/forum/showthread.php?101137-quick-question-about-Skydoc-s-clutch-upgrade&highlight=clutch+replace%3F

 

and here...

 

http://www.venturerider.org/forum/showthread.php?99519-Clutch-Upgrade-using-Skydoc_17-Kit

 

david

Edited April 23, 2015 by videoarizona
added another linkie goodness