Author Topic: yz490j 1982 timing  (Read 1098 times)

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RMJJ

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yz490j 1982 timing
« on: May 31, 2009, 08:47:36 am »
Help required fellas
Looking at my mates 490. it keeps flooding when starting. its a damn bugger.
I know the 490 has a reputation but I'm trying to get everything to standard and work from there.
The timing is suppossed to be 2.7m btdc but in the manual I have for it, it says to rotate the rotor clockwise.
When I do this the timing marks are about 15mm out but if I do it anticlockwise its spot on.

I'm trying to determine if I am dong something all wrong and cant see the woods for the trees or if the rotor is the wrong one. The numbers on the rotor are R3T210

Can anyone tell me if this is the correct/wrong rotor or am I dong something obviously wrong.

Its doing my head in now, it runs nice when it starts and in a race it runs well, its just a real bugger to start hot or cold.

211kawasaki

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Re: yz490j 1982 timing
« Reply #1 on: May 31, 2009, 07:02:53 pm »
In my experience never take any mark seriously - ever. Find TDC with a dial guage and the rotate clockwise (on my bikes anyway) the required distance. My Suzuki 400 is 3.2mm BTDC and my 250 is 2.6. 2.7 on such a big bike seems awfully advanced to me.

There is a book 2" thick on the subject of getting it right with these big Yamahas - good luck.

211

Offline evo550

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Re: yz490j 1982 timing
« Reply #2 on: May 31, 2009, 07:45:41 pm »
How are you doing your timing?
You will need a dial guage to find top dead center then rotate rotor back 2.7 mm on dial guage. Then rotate stator plate so the mark on stator lines up with the mark on rotor.

Offline Lozza

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Re: yz490j 1982 timing
« Reply #3 on: May 31, 2009, 11:56:23 pm »
A small point here, the marks really mean very little unless you strobe the engine, and see if the static timing mark and your TDC reference mark on the cases line up at XXXX rpm.
Jesus only loves two strokes

RMJJ

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Re: yz490j 1982 timing
« Reply #4 on: June 01, 2009, 07:26:35 am »
Thanks fellas, managed to sort it now.
Yes was using dial gauge.
I have a strobe and am going to check it with that in a couple of days. My trouble is the miserable old fart neighbours moaning when I fire it up.

Anyway it starts first or second kick hot warm or cold now and runs nice.

Thanks again.