2005 Mix spraying out back side of carb and snapping the slides + Video

[slug]

When at idle the bike till make a sound like it is backfiring but i believe it is the plastic slides that control air flow from the air box are slamming down creating a snap noise. The bike runs great besides this and it only happens at idle or returning to idle. I took the air box off and you can see some mix spraying out of either the left or right side, but not both at the same time.

Carbs are new from a 2009 gs (only had 3k miles on it)

My friend and i have done a bunch of work on this bike when there was a hanging idle - here is a thread
http://gstwins.com/gsboard/index.php?topic=67710.0

Here is a video of what is happening
https://www.youtube.com/watch?v=gyzU1HxL1sU

any help would be much appreciated.

Thanks!

[JAS6377]

I'd probably start with float height and inspecting the diaphragms.

[slug]

I just threw on new (3k mile) carbs on and this same thing happened with the old carbs, the new ones looked in great shape before i threw them on so i don't think its the float/diaphrams

[Alan_nc]

Lets back up a bit.

Why did you put new carbs on the bike?

It would seem that the problem isn't the carbs as you have the same problem.

Have you set the valves lately?  Almost sounds like a valve isn't closing and when the piston comes up it is pushing air back through the carb.

[slug]

It all started when my left cyl stopped firing and it had a very high sticking idle about a month and a half ago

My friend and i replaced valve shims to correct spec, swapped coils, lightly honed cylinders , replaced exhaust valves (and seals),  seals between crank case - cylinders - head - valve cover, oil and filter. Measured and replaced shims again. And ofcorse (using propane) checked all over for air leaks.

We got the left side to start firing again but tried everything to fix this high sticking idle. the bike would make this click noise when idling low, but this rarly happened as it liked to climb and hang at ~4k rpm. I gave up about a week ago after no luck for a few weeks and just bought some carbs from 2009 that had 3k miles on them thinking "carbs are usually the issue" the bike now doesnt idle high but this means that "back pressure" happens alot more as it only seems to happen at 1-2k rpm

[prmas]

Is it possible that the inlet cam is 1 tooth out? You say that it idles well but it does not sound like it to me. Mine is much smoother and very even at idle unlike yours. My first step would be to recheck the cam timing. 

Macka

[bombsquad83]

Is it possible that the inlet cam is 1 tooth out? You say that it idles well but it does not sound like it to me. Mine is much smoother and very even at idle unlike yours. My first step would be to recheck the cam timing. 

Macka

Definitely check this.  Also check for a sticking bucket on one of the intake valves.  The bucket should easily spin while the cam is not pushing it down (same position you would check clearance in).

[slug]

Some else i just talked to said this could be the problem. I will open it up today, i swear i double checked it tho.

[slug]

Ok so i opened the top up today and this is what i found.

You can't tell in the photo but the 1 is pointing forward. And there are 100% 18 chain pins from the 2 arrow and 3 arrow on the inlet cam.

The thing that seems off is the pick up i watched a video and they say that you should line up the RT mark on the pick up when the 1 arrow is pointing forward but i don't think mine is. can anyone tell if this is off? Should the pick up line up with the 2 hashes after the RT? it wasn't very specific. This photo is with the 1 arrow pointing forward and the cam notches facing each other.


[attachment deleted by admin]

[slug]

Definitely check this.  Also check for a sticking bucket on one of the intake valves.  The bucket should easily spin while the cam is not pushing it down (same position you would check clearance in).

Buckets spin easily

[gsJack]

The R-T mark is the line closest to the R-T letters with the #1 arrow pointed at the heads top finish so your off a bit.  Pin 1 lines up with arrow 2 and pin 18 lines up with arrow 3 as shown in this diagram.  I put this together from diagrams in the shop manual:

http://img.photobucket.com/albums/v443/jcp8832/gs500signalgenerators_zps2134172a.jpg

[bombsquad83]

The R-T mark is the line closest to the R-T letters with the #1 arrow pointed at the heads top finish so your off a bit.  Pin 1 lines up with arrow 2 and pin 18 lines up with arrow 3 as shown in this diagram.  I put this together from diagrams in the shop manual:

http://img.photobucket.com/albums/v443/jcp8832/gs500signalgenerators_zps2134172a.jpg

There's your problem!

[slug]

Running so much better! During warm up it still sputters sometimes but after about 1-2 mins of running everything seems great

Thanks for the help guys!

[bombsquad83]

Running so much better! During warm up it still sputters sometimes but after about 1-2 mins of running everything seems great

Thanks for the help guys!

So was it off by one tooth on both cams?

[slug]

Yep, can't believe the bike still runs with it off like that

[bombsquad83]

Glad we could help you figure it out!