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flashman
27-05-07, 10:50 AM
What is the correct way to check and adjust ignition timing on a gpx 250.
Ray

MIKER
27-05-07, 11:39 AM
^^
sorry mate , i cant help ..

dude880GPX250
28-05-07, 08:43 AM
hi mate i downloaded a manual from here http://www.bettermoto.com/motorcycles/index.php?ACT=register all you have to do is register and it will let you download max of 2 manuals in a month but thay help so check it out http://www.bettermoto.com/motorcycles/index.php?ACT=register

flashman
29-05-07, 10:14 PM
I downloaded the manual, it gives me the timing spec's but does not tell me how to do the check. I presume that you need to shine a strobe light through the top of the clutch housing:confused:
Ray

wheelbarrow
29-05-07, 10:17 PM
I know nothing about the 250 but does the manual tell you where the timing marks are? Just a thought.

graham979
30-05-07, 07:25 PM
There may be no need to adjust timing because it is fixed on a lot of bike now.

planezrx
31-05-07, 09:11 AM
I know nothing about the 250 but does the manual tell you where the timing marks are? Just a thought.

I don't know too much about 250's either, but I'd hazard a guess to say that you have electronic ignition and therefore the timing is set at a particular setting.

The marks on the ignition rotor (on the end of the crank shaft) are there so that you can psition the pistons correctly when you are performing a valve adjustment.

http://i11.photobucket.com/albums/a160/PeteLane/Valve%20Adjust/ValveAdjust017Large.jpg

The way to adjust the timing is by replacing the ignition rotor (Ignition Advancer). Mine has been changed from 2.5 degrees before TDC to 4 degrees before TDC.

Cheers,
Pete

MIKER
31-05-07, 09:38 AM
^^
i dont mess with ignition timing myself , but thanks for the pic ..

btob
31-05-07, 09:52 AM
^^
i dont mess with ignition timing myself , but thanks for the pic ..

Isn't the timing on the new bikes with fuel injection regulated by the ecm (brain)? Or is the timing still adjusted manually?? :confused:

planezrx
31-05-07, 11:43 AM
Isn't the timing on the new bikes with fuel injection regulated by the ecm (brain)? Or is the timing still adjusted manually?? :confused:


On fuel injected bikes, yes.... On old antiquated bikes like the GPX and the ZRX that run carbies, they just have electronic ignition. Sort of a very basic ecm I suppose.


^^
i dont mess with ignition timing myself , but thanks for the pic ..

Changing the ignition rotor was the first mod I did to the ZRX Mike. Took me all of an hour and a half!

It didn't do anything noticable to horsepower, but made the throttle responce much crisper.

Cheers,
Pete

MIKER
31-05-07, 11:44 AM
^^
thanks for the heads up "pete" .. ;)

flashman
02-06-07, 07:56 PM
Thanks for your help boys:)

Ray