TOPIC: New (old) previous member from old forum...

Good evening, gents....

It's been awhile since I last posted anything, I've been away from it all through work and family stuff. My old moniker was Headley, but that's in use now..A question if I may...the last time out with my 1964 650 4cyl. it ran like a bag of poo...it started missing, surging and more alarmingly, it sounded like it was pinging under higher revs and load. I nursed it back to the dock, ran it dry and winterized it for storage. Gas was premium with Merc synthetic oil, fresh fuel pumps and plugs. Could it be a fuel issue or maybe the original coil is breaking down with heat? Points and condenser are fresh, but I haven't taken the fuel inlet screens out yet. Possibly plugged? Ran like a swiss watch the previous two times out, longish runs pushing through 25 gals. each outing. Timing and synchronizing?? Any help at all would be greatly appreciated.

Thanks, John

could be a bad cap or fuel issue. ping could be a cracked flex plate.just reaching check basics first.

Hello Dave, and thanks for the response. I'm in the process of stripping things apart and I'll go over all the basics plus some. I have new carb rebuild kits for the 650, but I still have to get some floats. I've never set the float height on something like this, but the instructions go over it, so i should be ok. You mentioned a possible cracked flex plate creating the pinging noise. Would you be talking about the reed plates? Sorry, but I've not heard of that name before. (still a greenhorn...)

thanks again for writing..

john

The flexplate is part of the flywheel assy. There is a centre hub which bolts to the crank & an outer ring with the starter ring gear & magnets on it. The plate that connects the two is the flex plate.

I have attached a picture of where to find cracks in the flex plate.
Thom

to check the flex plate tap it with a wrench it should be a nice ring to it not dead sound.sometimes you cant see the cracks.

Hi John,
Thinking about your problem, what could have changed between the time it ran great and the next time out? OR what could have failed upon start-up. I would not suspect flywheel cracks, or dirty filters, condition would not have changed while sitting, nor would this be a start-up event. Did you repalce the points between times? It's hard to tell from your description.
Fuel gone bad or contaminated with water comes to mind, this could happen during storage, but again hard to tell how long it sat between outings.
Impellors can fail suddenly at anytime, if it was marginal cooling on previous outings and you lost a vane, maybe motor is now overheating which would run rough and PING! This is bad, check impellor.
I have also seen the black plastic points arm crack on newer points sets, and this creates obvious ignition issues. It's a remote chance but I've seen it happen. This happens suddenly and would result in erratic timing so motor would run poorly.
So I vote for a gas condition, impellor and possible points check.
Good luck!
Randy