can't solve rough idle

[gearhead13]

What part of Vancouver island do you live?
I am in victoria.
I could try to help out if you could come by.

[TheCafeKid]

Uhmmm. I didnt see anything about replacing the AIRBOX BOOTS.... They are rubber, they shrink, they get old, they dont seal...they make sucking noises like a kitten on its mothers teat...

Also, I know your floats are BRASS, but they will STILL develop leaks from time to time....If they fill with gas, they will sink, the fuel flow wont stop and the bike will drown. Did you check them? Youve done alot, and I applaud your efforts. Dont give up now! Its almost there. Its riiiiiight in front of your nose... You just have to uncross your eyes to see it. Bikes are simple when you get around the frustration...

It only needs three things
AIR
FUEL
FIRE

its getting too much of one or more of these things...

[trippivot]

a rough idle has only a couple causes.

you have the mixture of fuel and air .

you have timed ignition .

you have the sealing integrity of the valve and seat.

it is a little oversimplified but essentially that simple.

if you are sure that you have checked everything:
I suggest removing a plug wire 1 at a time. when you do this you are looking for the cylinder where removing the wire does not change how it is idling.
what that tells you is that you have a mechanical sealing problem between the poppet valve and valve seat in the cylinder head. time to remove the head and get a valve job.

[azr]

Yes the airbox boots have been replaced. As far as I can see the floats are working fine, but yes it is getting too much fuel. There is remnants of fuel in the intake boots, airbox boots. I've checked the spark, good, done a coil mod, good, checked the coils, good. Airbox has been rebuilt, twice, new airfilter, no air leaks. I'm sure I"m missing something simple (I hope). I did my compression yesterday 125, 125, 115, 125. Curious about the 115. I'll try removing a wire at a time, will be interesting to see the results. Hey gearhead13, thanks for the offer, I'll PM you.

[rustybronco]

At this point, if it hasn't already been suggested, I would make a tube to fit in the carb drains to externally check the fuel levels for each carb.

[azr]

Update. Tried taking off one plug cap at a time but didn't make any difference. Replace a shim that was just on the edge of being tight. Put the fuel and air screws at 5/8 and 1 1/4 (which was no way close to what the colortune had them set at, some were 1/8 and 2", go figure). The bike ran way better, sort of until I tried to run it hard then same old same old except a bit better rpm in lower gears...arrrrr...so...decided to pull it all apart again (why not) and fix the leaking and what apeared seized cam tensioner. Fixed that (nice to not have it leaking) but now its running a bit worse....ha,ha,ha....picked up a better voltage meter, checked the coils (with a bit of help from here) and it's showing both coils are no good (0.7 ohms on the primarys and 20'000 on the secondarys and thats with the stock points. So....if anyone has advice on where to get coils that won't break the bank that would be great.

[azr]

update

Well it turns out the coils are fine. With the help of Gearhead13 leaned the floats out, all are set at 24. That seemed to help. Before they were more on the 23 side, and I was setting the floats by letting the float fall on the spring loaded needle by gravity, instead of measuring as it just touches. Valves are all set. Points are done and timing. I was told my dwell shoud be about 22.5 but I am getting 42 on both. I figure as long as they are roughly the same it should be fine. Seems most people on here don't use a dwell, feeler gauge is more than good enough. The air and fuel mixtures are at the stock settings. So..the bike is running better, pulls better from a stop and the idle is better than before, but still has a rough idle, stumbling, and anytime I try and push it past 5000 it bogs, doesn't matter what gear. While we had the carbs apart I finally tried moving the clip down, so its now in the middle, 3rd from the top. But no improvement. On Gearheads suggestion I've ordered another set of 102.5 mains as mine were looking a bit worn. I have another bank of good carbs, so when those main come in I'll have another bank to throw in and try. I'm going to leave those clips at 2 since moving the others didn't seem to help. ....the saga continues. But on a good note while muckin about I painted the rear caliper, looks way better. So she's on the road once again, ha,ha,ha.

[gearhead13]

I would say that the difference in spark performance between 22.5 and 42 is quite large, doesnt matter that they are the same, imho. Changes your timing as well.

[azr]

I've got the points set towards the narrower side of the specs right now. If I try and bring the dwell down further I will outside of the specs. I'll try setting it again though with the dwell meter on while I change the points gap. I suppose I set both points and then do the timing. I looked around a bit and found some other specs that taked of 45-49 for the dwell. And actually it looks like a dwell meter isn't the most accurate as they are designed to work on a car which doesn't rotate as much as the DOHC.

[gearhead13]

As I remember when i used a dwell meter, I think it had a selector for # of cyls, so your 42 could be 1/2 that at 21 degrees.
If it were me and I could afford it, I would go with a dyna-s on there, points are a pain.

[azr]

down for the count

Well took her out for a ride with the girlfriend for a couple of hours. Died several times. Would loose all power, RPMS would go up but she would just bog. Blew a hole through the right muffler that got bigger and bigger.. and one rear shock blew out, nice (nothing to do with her weight!) so...now I'm looking at do I repair (or probably a full rebuild with all the problems I've been having or scrap her and try and find a better one to start with....arrrrrrrrrr

[Macguyver]

Hang in there.

I am in pretty much the same boat right now. Same symptoms.
I have done most of the same procedures(multiple times), and I am getting a little weary of it as well.

Yet I am still going to proceed with trying to get the old girl running right.

I had a crazy thought the other daywhile doing a road test. It seems my engine gets very hot, hotter than I would like, even on short trips up a concession road and back. I am going to put a couple of the temperature dot indicators on it and go for a run to see how hot she really gets.

I was wondering (feel free to say I'm nuts), but is it possible one of the oil passageways is not getting flow? Gunked up? The resulting loss of cooling and lubrication from the oil could cause the metal to expand and contract in an unpredictable manner, maybe causing drag in the engine?
How clean was your oil last time you changed it?

Has anyone heard of something like this happening? I know the engine is designed to handle oil as a low pressure operation, maybe it doesn't have enough pressure to keep the passageways clear? Have you tried seafoaming the engine yet?

I think I am going to pick up another can of seam foam from work and let it sit for a day before running it out. In the oil and just to make sure, in the carbs as well.
This is just a longshot, but you never know. If I find it improves my engine, I'll let you know, maybe it will do something for your bike.

[gearhead13]

Put 1/2 the can in the oil, 1/2 in the gas tank, run it long enough to circulate it, and let it sit.
I think that if there was enough friction to make your engine overheat, it would start knocking louder and louder then die or sieze. How do your plugs look? are you running lean?

[Spyderman]

..arrrrr...so...decided to pull it all apart again (why not) and fix the leaking and what apeared seized cam tensioner.

umm just a thought but
if your camchain tensioner was seized (has it been fixed free moving and tensioning the cam chain properly )

have you checked the cam timing cause if the tensioner was seized and the chain was loose then it is possible that the chain jumped a tooth or 2 and well it won't run very well if the cam timing is off by even 1 tooth
so at this point i would look at the cam timing and see what it has to tell you

[azr]

Over heating is a good thought, I've always thought the engine was too hot but don't have anything to compare to, and like Gearhead, I just thought I would 'hear' it overheating. I've done the seafoam but only in the gas, in the oil's a good idea. I've done my oil changes and they've been sorta dirty but nothing in the oil to worry about. I fixed my oil leak at the cam tensioner and thought the same thing about skipping (was a bit excited thinking that could be it) but I pulled the cam cover (again) and checked and all is good, teeth are fine, markings line up as described in my shop manual. At this point I've ordered a new set of Hanell exhausts, I'm putting together a new rack of carbs with new mains and we'll see what those do and the new exhaust is bound to help. But I am not holding my breath about either. I've thought about ordering a new pair of coils but I know that's not the problem since the rough idle is there cold as well. I'm actually thinking there is damage to the valves that I'm not aware of.