Just a quick note. When I got my bike the plugs were running white. This was a concern on a bike that is known to melt pistons. I increased the jet size twice from .92 to 1.04 before the plugs were running a nice straw colour. The added advantage was that the bike is running cooler and also is accelerating a lot better. It still sucks fuel. 8.5 litres per 100km on the open road.
Flip, what carbs and motor do you have? I've got an M1M with the improved carbs. I've just bought it and working through repairs for a wof. It runs like crap, carbs are miles out of tune. Any info/help would be great.
Mine is a side valve with the basic 28mm (but new) carbs. What is the history of your bike? Post Pics of the bike and the carbs when you can. Mine was running relatively well when I got it, but it did run very hot and the plugs were white. 1, Check the ignition is right. 2, Check that fine filter that is under the main jet is clear, mine was partially blocked. 3, Check the fuel tank filter is clean mine was blocked, remove the fuel tap to check. 3, Check that the carbs are balanced correctly both the idle and throttle opening is symertrical, there is heaps of pages on the web how to do this. There is a lot of pages on the web about correct jet size that all say 1 to 1.05mm for both the ohv and the SV motor. You might check with CJ750 your bike sounds a lot like his.
Thanks Flip, I've got it running a lot better now. Carb sync was miles out, one side the slide was up 10mm before the other moved. After lots of checking the only answer to this was one cable shorter than the other. I put a tube spacer into the carb cable adjuster and got it close. Also checked the valve clearances, 3 were quite tight, this made a big improvement when fixed. I still have one cylinder running rough so will keep checking, I'll go through your list. This bike has been in Wellington for 5 years, it's all black and chrome, the chrome is rusty. The guy I got it from bought it from a mates mate who brought in 2 and kept one for himself. He paid 7200 for it complied and registered. I looked at bringing one in, it was roughly 8 grand plus.
Checked the ignition, points gap was closed up, made a big difference when it was sorted. I drained the tank and unscrewed the fuel tap, was blocked up with gunk. Overall running a hell of a lot better but rich on the RH side. Can't seem to improve it, need to do some more reading on the web. I checked barrel temps both sides with an infrared temp gun, RH side is about 20 degrees lower than left.
Before you try to balance carbs, it is a good idea to check that the main jets are the same size. Do not believe what is stamped on them. Mine had .92 on one side and blank [no stamping on other]?????!!!!!. Also note that the slides can go in two ways, a right way and a wrong way. Just to edge the bets, my set up had one each way. Correct way is for taper to the carb inlet [air cleaner side]. Check also that carby heat shield gaskets do not leak air. Previous owner had all servicing done by a commercial garage mechanic. Probably had never seen a carburettor before. Runs much better. Now to balance the set up.
