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Sun Jan 05, 2003 1:13 pm

I have a bone-stock 1200 that I just replaced the clutch on. The pressure plate rubbed on the inside of the bellhousing, so I clearanced where it was bumping and now I have a new issue. When I get going in first, the motor revs right up until I hit about 5 mph. Then it sounds like the motor really struggles up to about 10. Then if I put it in second and try to accelerate it loses speed and begins to backfire real bad. If I come to a stop after shifting out of a gear it wants to die on me. If I'm just sitting there in neutral, I can rev the motor up all day long and it will never miss or backfire and will not try to die when I get off the gas, but it occaisonally backfires on startup if I have to feather the gas. Anyone have any ideas what it might be? The first thing i thought of was timing, so I reset the timing which was off because of a loose cooling fan, and I'm just wondering if I may not have a burned valve or a weak valve spring. But it only backfires under a load and it has no power whatsoever. I'm getting ready to run a compressing check, see if it says anything. It wasn't doing any of this until I replaced the clutch.

Sun Jan 05, 2003 3:25 pm

Sounds like your motor is fighting against your clutch. If all things were fine till you replaced your clutch I'd make sure the clutch set up is right first. Are you certain you have the correct pressure plate? that might be the rubbing issue that first came up that you tried the clearencing. I bought a new clutch disc, pressure plate,for my bus many years ago and the new part was off by 1/32 and it was rubbing and making all kinds of noise, instead of trying shimms I returned it and got a correct plate and all was right again. I would start there and not risk damaging my motor. The 1200 bell housing is smaller than the later units, when you order parts you can get hosed real easy, I'd first make sure my replacement parts are correct. If you don't have one already, get a bently manual as they are the best books to refer to in these types of situations.
Good luck and keep the faith

Sun Jan 05, 2003 5:18 pm

I started by going back to the place I bought the plate from, and they compared it to another an they were the same (these are 200mm plates). I watched so I can attest to it. Just ran a compression test and I had 2 cylinders test at 90, one at 60 that went to 90 with a shot of oil, an one at 70 that went to 80 with a shot of oil. Looks like it's time for a set of rings. The rings were probably borderline and the shocks from the plate hitting the bellhousing probably pushed them over the edge.

Sun Jan 05, 2003 5:35 pm

So your bone-stock 1200 is 12v. And you know 6v is 180?

Mon Jan 06, 2003 1:44 pm

that isn't bad compession for a 1200.not bad enough to run that bad! do you have to stock vacuum advance dist.? maybe the vacuum unit went bad or the line from it to the carb is bad or disconected ? other things to check is something stuck in the main jet of the carb? or bad condenser or points? whatever it is has nothing to do with the clutch. good luck steve

Mon Jan 06, 2003 8:51 pm

My bonestock 1200 IS NOT 12v, it is still 6 v. I installed a flywheel off of a '65 bus (6v dimensions, 200mm face), and before you even ask, yes, I did reset the endplay. As for the vaccuum advance unit it is operational. The vaccuum line popped off once and it didn't even run this bad. points are good which points to a good condensor, carb is not plugged up (all things I already checked). I'm sticking rings in it anyway, then i'm gonna spray paint the inside of my bellhousing, reinstall the motor, and see if anything might still be rubbing, also going to check the all the valves, I think one might be burned on cylinder 1, it's the one that read 70 and bumped up to 80. I have until Saturday to get it to run, so it looks like i'm gonna be in the garage quite a bit.

Mon Jan 06, 2003 10:54 pm

Did you do anything to your plug wires at all? I'm embarrassed to say that the same thing happened to me and it turned out to be my wires were on in the wrong order and they were mis firing.

Tue Jan 07, 2003 2:14 pm

already thought about that one, plug wires are right. Along the lines of waht sgmalt46 said, the main jet isn't plugged, but someone else said to look into fuel starvtion, gonna see if the fuel line might not have gotten bent or kinked.