Installed, runs great, Knocking at acceleration

2-Skinny

As stated, knocking comes when accelerating from idle or accelerating from idle in wrong gear, etc. Only when the bike is well hot and its warm out (85+). Any ideas? Do I need to retard timing? Colder/hotter plugs? More fuel? Otherwise bike runs smooth.

pamcopete

2-skinny,

Check your maximum advance at 3,000 RPM. I forgot what model bike you have, but if it is a '72 to '79, there is a mark for maximum advance.

It's also possible that you are getting the proper maximum advance, but it happens too soon, at lower revs, so watch the advance as you increase the engine speed. It should not get to maximum until 3,00 RPM. If it goes to maximum sooner, then you probably need new advance springs or you can try bending the end of the springs to make them tighter.

If all of this checks out OK, then just use a higher Octane gas, like 93 Octane, and don't buy the cheap stuff.

Other possibilities would include using pod filters without changing the jets to a larger size.

The problem, whatever it is, will be worse in very hot condiiotns, so you could also try a set of xsjohns needles to give you a more uniform mixture and help cool the engine down.

Put a fan infront of the engine when doing these advance tests.

Riding habits are a factor as well. I am in the habit of shutting the engine off at long red lights. I also do not accelerate harshly after waiting for the light, or in stop and go traffic. These are air coled engines, so the higher ambient temperatures can cause them to over heat which can cause knocking.

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Yamaha xs650