Bike 'banging'

[john2]

Hi,

I finally got my bike together, but it is 'banging' when I first start it.

Is it because:

Needs a 'advanced key timer'?
I used 1 week old fuel (unleded)?
Needs to be tuned (on stock settings)?

Can I use premium in it? Or do I need an advanced key?

Thanks,
John.

[Brandon]

u mean u didnt mix 2 stroke oil into the fuel

[SAMMY]

i always use premium unleaded and mix it with 2 stroke oil

[SAMURAI47]

it means its leaned right out and/or the timing does need to be advanced, which carby do you have? let me know that ill tell you how to fix this problem.

[mac90]

what do you mean by banging
id be pulling the engine down & inspection the squish
to make sure the piston is not hitting the dome or plug

also make sure your spark plug has the washer on it i have found a there few plugs without the washer & this will cause the piston to hit on the plug electrode

[RD RACING]

yes it could be the head clearance, if your engine still runs with this banging sound its not sparkplug rod end clearance as the problem. as mac90 mentioned firstly check your squish clearance then if it still does the bang i would remove the head and check the piston bearing to conrod as some bearings are not the exact size. just hold the piston in one hand and move it up and down without turning the engine to see how much play there is between the bearing and the little end of rod. if you feel there is play you must replace this bearing. i have noticed this before in cag engines with replacement bearings that are designed for piston port engines , the diameter is about .5 mm difference.

[john2]

It is the sound out of the exhaust that sounds like 'banging'

I have a HP carb ans stock timing key atm. (stock exhaust too)

[john2]

Ok, I gave it a run in the rain.

Only, when it gets to full throttle it dies.

Would the rain make any difference(water in thing)?

[mac90]

id be pulling the cylinder & head off & inspecting it as you could be causing internal damage if the squish is incorrect or as RD said there is play in the bering

[john2]

Its ok now; only when it gets up in speed it is not going smooth.