SOHC.co.uk Forums > CB350/400
Adjusting points/contact breakers driving me insane!
K2-K6:
If you have decent spark it seems you're more or less ok on routine of setting them.
The point earlier about something assembled wrongly, you can assemble the rotating part of the advance and retard mech at 180 degrees out (the cam lobe being in the wrong place) which would put the timing at near bdc!
You can do a quick test for that by swapping the two coil to points wires over with each other to see if it fires. If it goes, then you need ultimately to correct the assembly and swap them back. But try it first to see if you get a response.
JezzaPeach:
Good point, or take a plug out and compare the piston position with the T mark on the plate.
TrickyMicky:
Just as an added point, I would NOT let Easy Start anywhere near any of my vehicles. When petrol vapour burns in the cylinder, it does so at a predetermined rate, (the old octane ratings), this is a small part of the reason for ignition taking place a little before TDC. If you use Easy Start, it burns so fast that it is virtually exploding, and could be the reason for your backfire, and feeling the 'kick' through the throttle cable. If ever you've heard an old diesel being started on Easy Start the sharp cracking noise is unbelievable, and knocks hell out of the bottom end. You often see adverts from people selling 'barn find' imported bikes that have stood for years, and they state that they have managed to get the engine running with a bit of Bradex. Thanks, but no thanks. I've just bought an old CL160, the dealer told me that he had not had it running, just turned it over on the kickstart to ascertain that there was compression, that was good enough for me.
On my 400, I still use points ignition. The one big problem I had some while ago was using a "Ready to Fit" fully assembled backplate. There was not enough movement in the adjusting slots to be able to set both points as required, so it became a compromise. This was followed by one of the condensers failing which gave me my 1st ride in an RAC Recovery truck!
I still had the OE backplate, which was re-installed along with new OE components from DSS. Bliss!
Just to show that I still push my luck, I use a cigarette paper to time my ignition! Please keep the replies polite!
Stay Safe. Mick.
K2-K6:
--- Quote from: JezzaPeach on April 30, 2021, 07:05:40 AM ---Good point, or take a plug out and compare the piston position with the T mark on the plate.
--- End quote ---
I think the marks stay the same as pegged to crank position, but just the cam lobe moving as it rotates independent of the other parts.
In effect it looks ok from initial inspection but the cam itself is 180 out from marks.
To swap it you have to swing the counter weights out of the way and swivel the cam then re-establish the weights.
There's some good pictures on here of the units with align check marks but I can't immediately find them.
Bryanj:
Its the fact the plate is a smaller circle than the hole formed by the posts,
On a really bad one i made 3 bent curved shims held by yhe screws that hold the plate and bend round the edge of the plate to remove any play, there are other ways and any that work without damage are OK
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