350 timing advance

The 3 1/2 forum
Post Reply
fastharry
Posts: 63
Joined: 06 Oct 2011 10:38
Location: leicester
Location: Leicester

350 timing advance

Post by fastharry »

Im working on a 1999 350 it wasn't running very well when i took it in, but that turned out to be a split carb rubber. It is better now it has 2 new rubbers but it do's not pull well over 60mph. it go's a bit flat , i strobed the timing and the front cylinder is advancing and i adjusted until it was spot on, It advances upto the mark but at about 6k it gets a bit erratic and it retards a bit, There is no mark for the rear cylinder but i noticed that front one is 2 fins on the flywheel so i put a mark 2 fins in front of the rear cylinder Tdc, when i strobed that mark it was way off, it was advancing but no where near the dot in the cam belt bolt, Am i doing this correctly ?
Attachments
20190315_165732.jpg
20190315_165732.jpg (356.74 KiB) Viewed 3831 times
User avatar
72degrees
Posts: 1549
Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: 350 timing advance

Post by 72degrees »

I have a flywheel with all four marks on my desk but it is an early one so they are positioned to line up with a crankcase mark - not the cam. However, the relationship between PMS1/ANT1 and PMS2/ANT2 is the same, but not a full two fins. But the non-electric start version may have a different number of fins perhaps?

If I find a tuit I'll try to be more accurate with measuring the spacing.
George 350
Posts: 450
Joined: 16 Jun 2007 09:43
Location: Northampton

Re: 350 timing advance

Post by George 350 »

Get a piece of masking tape, stick it on the flywheel so that it covers the ANT1 and PMS1 Mark's. Using a pen, mark where the 2 lines are.
Peel off and stick it back onto the flywheel so that the mark that was on PMS1 is now over PMS2.
You now have a 'ANT2' mark on the tape.
Provided that the flywheel was grease free it will stay in place while you do the timing check.

George

PS: my old red pickup behaved just as you describe and it didn't rev out. I fitted the NLM pickup and all was well.
George
350 sport 1978, 350 Strada 1978
650 Norton 1967, 650 Kawasaki 1977 and 650 Enfield 2019
User avatar
P&S
Posts: 84
Joined: 21 Oct 2017 18:18
Location: Rome Italy
Location: Roma

Re: 350 timing advance

Post by P&S »

Could anybody post a picture of the NLM pick up please?
mad muller
Posts: 182
Joined: 19 Aug 2011 11:29
Location: liverpool, england

Re: 350 timing advance

Post by mad muller »

i may be wrong on this but 6k 0n the rev counter would propably be full advance on the ignition, iam, sure ive tried this when had probs similar to what you describe ,i fitterd a slack timing belt and the the timing marks were jumping around, try another belt , if you have one just a thought. muller
Post Reply