"TSK" noise 1988 GS450

[Guest]

I have a thread in project section, but I figured this question would get more noticed in here.. While my bike is idling it will randmoly make a "TSSSK" noise that you can see moves the carb and you can feel in the bars.

Here is a link to the video of it doing it (you can hear it around twelve seconds and again around 23seconds

https://www.youtube.com/watch?v=5txlmsDjIbI

[greg78gs750]

this video is private...

[chris032188]

I'm a moron - video isnt private anymore.

[tkent02]

Obviously it's burning all of the fuel / air mixture between the carb and the combustion chamber. TSK noise then the engine slows, as theres nothing there to burn the next stroke. Check valve clearances, cam timing and ignition timing, also just being too lean will do that. Something is letting the flame get out into the intake.

[chris032188]

Obviously it's burning all of the fuel / air mixture between the carb and the combustion chamber. TSK noise then the engine slows, as theres nothing there to burn the next stroke. Check valve clearances, cam timing and ignition timing, also just being too lean will do that. Something is letting the flame get out into the intake.

Thanks bud - appreciate the response

[chris032188]

Thanks bud - appreciate the response

Ok - I just messed around with bike a little (I haven't checked timing or clearance yet, but I did notice something).

The exhaust on the bike is hollowed out. If I hold a rag at the right exhaust (only on the right side) and create some back pressure in the pipe it stops the noise.

Anyone with more knowledge then me would have any idea what this indicates?

Also anyone have a good recommendation of a feeler gauge top get for this job?

[tkent02]

Ok - I just messed around with bike a little (I haven't checked timing or clearance yet, but I did notice something).

The exhaust on the bike is hollowed out. If I hold a rag at the right exhaust (only on the right side) and create some back pressure in the pipe it stops the noise.

Anyone with more knowledge then me would have any idea what this indicates?

Also anyone have a good recommendation of a feeler gauge top get for this job?

It's lean.

Blocking the exhaust makes it less lean.

[chris032188]

It's lean.

Blocking the exhaust makes it less lean.

Gonna try and riddle your mind real quick.. Now since one cylinder is leaner then other (atleast thats how it seems) should i richen up just that side or do both equal like it is now?

[tkent02]

What maintenance have you done so far?

[Mekanix]

That tsk is a misfire, If you've done the maintenance, chances are the carbs are not set up for a free flowing intake or exhaust.

If not, clean the carbs, check the jet sizes, check the valves... lots of little things.

[tkent02]

Not misfiring, it's firing outside the combustion chamber, between the carb and the engine.

Either firing when the intake valve is still open, or it's lean.

[chris032188]

What maintenance have you done so far?

New r/r and stator, and cleaned the cab.

Ordered a set of feeler gauges and the tappet depressor to do the valves on last night so I'll be doing that.

[chris032188]

Well did the valve check right exhaust was .1 with a 2.60 shim in there so I ordered a 2.65 shim - hopefully this fixes the problem