spits out intake and exhaust. high idle when stop

Hey everyone! I'm a proud new owner of a 1981 csr 1000. It's been sitting for 2 years and not ridden much over the recent years. I have no contact with the previous owner (he had a stroke and is badly demented)

the problem I'm having is this. the bike runs wonderfully, but when I come to a stop, the engine works its way up to about 3000 rpms. if I bog it down by letting up the clutch, she will come back down temporarily but then sometimes work it's way back up. it is also backfiring pretty severely whenever I let up off the throttle and it's winding itself down. and sometimes spitting feul out of the #1 carb air filter pod. I don't know anything about this bike. can anyone please help?

Sounds like a intake tract air leak. If the bike has been sitting for a long time, the rubber intake boots can dry out and crack.

With the bike idling, spray each intake boot with something like wd-40. (not too much, you dont want a fire!) If the idle comes down momentarily you've found your leak.

thanks! and do you have an idea about the backfiring and feul spitting back through the carb?

hwrecker wrote:

thanks! and do you have an idea about the backfiring and feul spitting back through the carb?

Fix the air leak first. It may be causing the backfire problem as well, but it could also be a bad plug in that cylinder, plug wire, coil (less likely), miss ajusted intake valve, bent or sticking intake valve.

Like I said, start with the obvious stuff first!

Intake boots are 55 bucks and well worth it !!!!

start with the boots and new plugs .

I did this just last week and have had great results!!

I sprayed wd 40 on the boots and it didn't do anything. I don't know where else there could be a vacuum leak from! the bike seems to have stopped doing the bad idle thing on its own, but now new problems.

after running beautifully for a week or two (minus a slight hesitation when you first roll on the throttle and backfiring) I was going down the freeway and it began to surge and lurch. slightly at first, then worse. now it will idle for a while then do something crazy! it had a small explosion come out of the air pods, and smoke came out of them for a little bit.

it is backfiring severely. also popping and i think missing. I have the carbs off now and am thoroughly cleaning them. they don't seem to have a way to adjust them. all four plugs were black and maybe fouled. the guys at auto zone said this is caused by the engine running far too rich. how can I lean it out? there only seems to be one jet! it does have k and N pods on it but they are verrry worn out.

I want to adjust the valves but I don't know what the clearance should be. it is an 81 csr kz 1000 m1.

this bike was my stepfathers. it is very sentimental. I'm a halfway decent mechanic, but i'm stumped. any ideas?

OK, this is starting to sound like an ignition problem. Does the bike have points or an electronic ign?

it has an electric ignition.

do you think I have to mess with the valves at all? that cover doesn't seem to want to come off at all.

1) you should do a complete carb overhaul.
2) the valve adjustment should be at about 5000Mi intervals.
3) it is not an ignition problem.
4) check to see that none of the vacuum lines leading to the top front of the carburetors are leaking.

I just got the valve cover off and I can't even begin to understand how to adjust them. I adjusted the valves on a 99 suzuki once but that was on a dohc and there were springs. it looks like you have to take the whole head off to adjust these???

there are no vaccum lines to speak of!
there is one line going from carb 1 to carb 3. one line going from the petcock to to carb 2, and I capped carb 4.

I took the carbs apart and cleaned them, but there doesn't seem to be any way to adjust them. there is only one jet. the other place (where I would assume a second jet would be) just has a plug on it.

the bike was running fine. just super rich and backfiring. how can I lean out the feul?? this new lurching/surging problem just happened. I initially thought that a leaky petcock had filled the engine with gas, it felt exactly like when that happened to my suzuki. changed the oil and got no response. It was spitting feul out of the carbs just once in a while, but then they actually ignited and made a puff of smoke.

I replaced all of the spark plugs, which were very blackened, and the problem still persists. should I need new wires? new coils?