bike is detonating, help

so since past winter my bike started pinging and detonating,

at 1st it happened once every 45 days.. with winter temps..40-75degrees

now it pings, probably 1-4times a day!. with temps from 55-90degrees

it happens everytime giving 60% or more throttle, 5th gear going uphill. 60-85mph

is my jetting to lean?

does it sound likes it detonating?

i set it up last summer for temps upto 100+ degrees.

carb setup:



dont know how many turns out.. lost info...

never touched carb since last summer,

i ride it everyday,

i fill up gas everyday from different gas stations

i tried to get it on video but in 5th gear there is too much wind noise and you cant hear it on camera

Edited by 707LAKE

Try setup the fuel screw first, jetting shouldn't make that much different as long as the fuel screw is adjusted when condition changes.

160/25, I guess you are running the Mikuni Carb. it sounds ok, I was running the same a year back all year around.

yes stock mikuni carb

The fuel screw will have no affet on a motor operated under load. That is just for idle and off idle transition.

Ping or detonation under load is the result of fuel burning in an uncontrolled condition. Generally due to fuel octane too low, ignition too advanced or compression too high.

You have not much control over ignition advance, you can buy higher octane fuel, you can lower the compression. You did not say what mods if any that might affect compression.

Over time deposits can build up in the combustion chamber and increase compression. Might be time to take the head off and clean things out. If it only pings under heavy load, just back off a little and live with it.

I had (have) and old GS1000 Suzuki that liked leaded premium, when leaded fuels went away it pinged like a mother. It just liked leaded gas. A rebuild mostly cured the problem.

+1...Try running high octane fuel would be the first thing to do.......

What needle are you using?...How many miles on your engine?...

Are you stock displacement? Have you installed a single base gasket?

motor is all stock,


never rebuilt

always use 91 which is highest they have for me here

You keeping up on valve adjustment's?

I think t is a combination of 33,000 miles and CA 91 (pump average octane) fuel. Live with it or rebuild the top end and clean out the combustion chamber.

The stock carb is jetted lean from the beginning, so it's not going to take much to upset the balance.....i.e. carboned up combustion chamber increasing compression, average grade fuel...

Noble has outlined a good plan..... :thumbsup:

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