TOPIC:

and has a bum leg.
Hi All, I put this in the engine forum because I have several general issues.
Introduction:
I was able to get her fired up yesterday for the first time in 11+yrs. The first time she fired up I needed to use ether and a bunch of kick starting. After she was running awhile I was able to stablize her idle at around 1K rpm, on full and half choke. When I go below 1k she stalls, and when I go to no choke she wants to stall, unless I keep the rpms up and then runs really rough w/some backfire. After I got her warmed up she fired up w/a little blip of the starter and maybe a quater kick. I must have started her a dozen, or more, times, all afternoon and into the evening. Pulled the plugs and they had a fluffy black carbon deposit. Today I expected to be able to just start it w/no problems and go on to other problems. Before I tried I pulled the plugs and cleaned them up just to get the best spark I could. I tried to use the starter and ran into a problem I've been having but thought it cleared up when I got everything loosend up after it's long slumber. More about that below. Since the starter didn't work, I started to kick it...no luck. I then went right to the ether, Bang started right up. Got her warmed up and everything stablized like yesterday. No problems starting it using the starter and the kickstart. Decided to do a higher rpm test. Cleaned the plugs and ran it a around 4K rpm for about 5 min and killed the power, got a little backfire. Pulled the plugs and they are still black but no fluffy deposit and looks cleaner, more burned than fouled. Since I was stumped on the engine issue, I started on reinstalling my front disk brakes. No problems hooking everything up and started the odious task of putting brake fluid into the systerm. Using the technique of putting a hose on the bleeder valve and putting the end in a container w/brake fluid. Pumped and pumped and bleed and bleed for a long time, got the pressure up, most of the black old fluid and no more bubbles came out of the tube but the breaks still feel really mushie.
Data:
I haven't adjusted the cam tentioner nor have I done anything w/the valves. The petcock is working correctly. I've totally cleaned and rebuilt the, Mikuni BS34 carbs, all new jets, including the o-rings and the little screen baskets on the float valves. Stock pilot needle w/no adjustment slots. Floats are bench adjusted to 18.6 +-.1mm. Air/fuel is adjusted 2.5 out from needle seat. Replaced #115 or #112.5 stock main jets w/117.5 and stock #40 pilot jets. Intake/exhaust mods which might effect the system are Mac 2-1 pipes and K&N pods, including crankcase filter.
The starter chain jumps the lower sprocket, when the engine is cold but works fantastic when engine is warm. I've already changed the chain, w/a less streached used, chain.
Brake caliper has been rebuilt by my used parts guy. I bought a used replacement master cylinder and brake line. I trust him to not knowingly give me bad parts.
Summery:
3 issues, Bad Idle, Mushie brakes and Starter.
Conclusions and Suggestions for subsequent experiments.
This is where you guys come in. HELP...Any thoughts or suggestions would be really appriciated.
The only thoughts I have are: maybe I didn't clean the carbs as well as I thought.
I may need to replace the lower starter sprocket.
I just need to keep pumping and bleeding the brakes.
Acknowledgments: Sorry this post has been so long but I've seen several posters be chastized for not including all information, when asking for help. Sorry, again, if I broke any group rules about combining and asking multiple questions in the same thread.
Thanks and I hope everyone is enjoying their Labor Day weekend:)

Even w/these issues, I'm really happy that she's been revived

Post edited by: ronjones, at: 2006/09/03 21:13

Have you checked the ignition system yet? If not, then I suggest checking the plug caps, wires, and coils resistance, all these suffer with age.

Are you sure the chain is jumping the sprocket? The sprocket would have to be totally shot for that to happen. Generally what happens on the 750 twins is the small round shoulder on the sprocket that the rollers engage gets hammered over time, so the sprocket will engage, release, and engage again, sometimes repeatedly. I have seen one sprocket on a 750 twin on which the teeth were bad, and on that one half the teeth were missing, in that case the chain came off and ate the stator.

Thanks for the reply, Steell.

steell wrote:

Have you checked the ignition system yet? If not, then I suggest checking the plug caps, wires, and coils resistance, all these suffer with age.

It's an electronic ignition, and unless the ignitor is bad I understand that the igniter is a works/don't work and if it doesn't work, nothing happens. I do have another igniter, I could try. I hauled her over to Dean's (my used parts guy) the other day, before I got it running and he found some stupid mistakes I'd made and also said that the spark wasn't as good as he would have liked to see.

Bad/weak coil, that is a good probability . Any suggestions for options?

Previously I'd brought my coil and wires to Dean to run some bench tests, at that time he trimmed some of the wires that had some corrosion. They then gave good resistance through the wires and plug caps.

Are you sure the chain is jumping the sprocket? The sprocket would have to be totally shot for that to happen. Generally what happens on the 750 twins is the small round shoulder on the sprocket that the rollers engage gets hammered over time, so the sprocket will engage, release, and engage again, sometimes repeatedly. I have seen one sprocket on a 750 twin on which the teeth were bad, and on that one half the teeth were missing, in that case the chain came off

I'm pretty sure. When I had the case drained and the covers off, I could see it jumping, the lower sprocket. Makes a god-awful racket . I also remember that I had occasional problems w/the starter, when I rode it before. When Dean gave the the less streached chain he also gave me a different upper sprocket. Got the same jumping and noise. The lower sprocket doesn't really look damaged. I thought it would stop, when I put oil in it. It almost seems that there is too much resistance when it's cold. I do get some kickback when I use the ether on the first couple of kicks, before it starts. It's like there should be a chain tentioner in there but there isn't, or the starter isn't seated correctly. Dean has also reworked the starter clutch, which was the first thought.

and ate the stator

Ugg ;ohmy: is that legal?...OH, you said stator...I thought you said Senator:)

Thanks for the ideas...keep em' commin'

BTW the bike is an '82 and has 17200 miles on it. I bought it around '90 and it had set in a shed for a couple of years, before I bought it. PO put most miles on it, does it seem that it was ridden hard in a short time? '82 to aprox '88-'90, 6 to 8 yrs?

Post edited by: ronjones, at: 2006/09/04 00:15

Yeah, I'm aware that it has electronic ignition, I just installed an 82 KZ750M electronic ignition on my 79. I could use a couple more if you run across any (pick up, timing advancer, and igniter)

Did you check the supply voltage at the coil? Should have near 12 volts there, if not, then a weak spark will result.

You should have heard my 79 wnen I tried to crank it when I first got it. The rotor bolt was loose and the rotor was bouncing against the engine sidecover

It had been loose long enough that it had chewed up the end of the crank, so when I tightened it, it spun loose again. Loctite works wonders

If the starter chain is jumping off the sprocket and slipping around it, there is a serious problem somewhere. The starter is supposed to be a fairly snug fit in it's mounting hole, amd you should not be able to wiggle it. Is that the case? Are the starter bearings good, as in no play in the shaft when you try to wiggle it?

I'm fairly familiar with the 750 twin starting system, having replaced a few starter clutches, a couple of starters, a couple of rotors, and converting two 76-77 motors to the later style charging system, on motors with anywhere from 7k to 30k miles on them, and I have never seen anything like you describe. I'm starting to wonder if you don't have a bent crankshaft or some other unusual problem.

Post edited by: steell, at: 2006/09/04 00:25

steell wrote:

Yeah, I'm aware that it has electronic ignition, I just installed an 82 KZ750M electronic ignition on my 79. I could use a couple more if you run across any (pick up, timing advancer, and igniter)

I figured you did, I just included that bit in the interests of clarity. I'll ask Dean, what he has in the way of ignition systems. He's where I got the extra ignitor, I have. Do you just want '82 M1 systems?

Did you check the supply voltage at the coil? Should have near 12 volts there, if not, then a weak spark will result.

No, I haven't yet, thanks for reminding me. Should I check it when the engine is running or not? How far off, 12v is acceptable?

You should have heard my 79 wnen I tried to crank it when I first got it. The rotor bolt was loose and the rotor was bouncing against the engine sidecover

It had been loose long enough that it had chewed up the end of the crank, so when I tightened it, it spun loose again. Loctite works wonders

Man, that's a bummer. Everything looks good in the rotor housing. The advancer mechanism was pretty rusted but I cleaned it up and WD40'ed it pretty good.

If the starter chain is jumping off the sprocket and slipping around it, there is a serious problem somewhere. The starter is supposed to be a fairly snug fit in it's mounting hole, amd you should not be able to wiggle it. Is that the case? Are the starter bearings good, as in no play in the shaft when you try to wiggle it?

Nah, the starter is pretty firm in it's mounting hole, it doesn't wiggle at all and I dont' feel any play in the starter shaft. I just threw that out as an idea to tighten it up, but I guess that's not a good idea.

I'm fairly familiar with the 750 twin starting system, having replaced a few starter clutches, a couple of starters, a couple of rotors, and converting two 76-77 motors to the later style charging system, on motors with anywhere from 7k to 30k miles on them, and I have never seen anything like you describe. I'm starting to wonder if you don't have a bent crankshaft or some other unusual problem.<br><br>Post edited by: steell, at: 2006/09/04 00:25

Sorry, If I'm stating the obvious to you, Steell. I know some of the twins had points, and if I didn't know I had an electronic, I might think some of my problems are points/timing related. I hope there isn't something serious like a bent crankshaft. Could my bad idle be related to that or would I even be able to get it to run as well as it does w/a bent crankshaft?
There was one odd thing, I saw when I removed the oil pan. There was this one very long bolt, it reached way up into the engine. It had totally come loose. It wasn't damaged and didn't look like there was any damage around it. I have no idea how long it had been like that but it must have happened when I was riding it before. I reseated it and tightened it. If the engine hadn't been upside down when I removed the pan it would have fallen out and I wouldn't have known where it belonged.
I always seem to have the strange problems no one else has ever had or even heard of I wanted to at least get it on the road, this fall. Then, if needed, do a major engine teardown over winter. The starter problem is, to me, minor because I mostly use the kickstart, but if it is something like a bent crankshaft, gittin' it on the road this fall ain't gonna' happin'. I might as well not get it tagged and insured until next spring. I've got to get into the alternator case anyway. I've got a leak and I may need to replace the stator, I think I crossed the 2 yellow wires and fried it. They are disconnected, now, and I've had the battery on a charging tender. I've wanted to put that off until I get another new gasket. When I do that I'll check for any wobbling in the shaft.
Thanks again for the help, I can use all I can get.

The very long bolt inside the motor sounds like a case bolt, one of the bolts holding the cases together, was it one of the two bolts inline that are towards the front of the motor?

If the crank is bent the motor is really going to shake, if the motor does not have a really bad vibration when it's running then chances are the crank is not bent.

Shorting the two yellow wires together might have a bad effect on the stator, (I'm not inclined to try it to find out), but it does not matter which yellow wire from the stator hooks to which yellow wire from the reg/rec.

The thing with the chain slipping on the sprocket is unknown to me, so I need to discover what's going on and why so I can add the info to my knowledge base, otherwise it will drive me crazy until I figure out the "why" part

I assume you have checked/adjusted the valve clearance?

11.5 volt minimum at the coils with the ignition on and motor not running is what I would look for. Battery voltage would be better.

440 or 750 twin electronic ignition componets will work, I can make the igniters, but I need to find the timing advancers and pick ups. Worst case I can use the slugs off the four cylinder advancers by pressing them off and flipping them over before pressing them back on the 750 advancer shaft.

I have a set of 82 KZ750 carbs disassembled in a box if you need any parts such as diaphrams/etc.

Keep bleeding the brakes, you are not done yet

I think you are not getting enough fuel at cold start, start a thread in the carb forum and maybe WG can help.

And check/adjust the valves, that very well could be important at this point.

Hey again, Steell,
That long bolt could very well have been a case bolt. I just looked on the parts diagram and it said that it was a 105mm bolt, which would have made it the right size. I really didn't pay attention to its positioning at the time. I just put it back where it looked like it belonged and tightened it up.
I'm really not getting a lot of vibration, it's running a little rough at 1krpm but not like you are discribing. I don't see any wobbling on the ignition rotor either.
I think that I may not have had the alt. wires insulated correctly and they may have shorted to the case, when I was trying to start it. The connectors look blackened.
I don't like having mysteries either. When/if I find out what's happining, I'll let you know. It could just need a shorter chain.
I haven't checked the valve clearance. When I had the engine out of the bike, I just didn't think about it. I wanted to stay away from a major engine teardown. I thought if the engine was working when I parked it, there couldn't be that much wrong in the engine. Would doing a compression test tell me if the valves need adjustment?
I'm getting 12v at the battery when the ignition is turned on and 12.75 w/the ignition off. I'm getting 11.25v at the coil. All the readings were done the charger disconnected. These reading would indicate that I'm not getting enough juice to the coil? Does this mean that I need to do WG's "coil bypass mod"?
I'll check w/Dean about those ignition parts.
Thanks for the carb offer, I have an extra set of body assemblies, that I used the diaphrams from. I was thinking of rebuilding those, to have a spare set. If I do I'll talk to you about the diaphrams.
I figured that I was just gonna have to keep pumping and bleeding the brakes. I just wanted someone to tell me I was wrong
Thanks again for the help and advice:)

Checking/adjusting the valves is not hard, and Z1 Enterprises has a few shims if you can't find them locally. No, a compression test won't tell you if the valve clearances need adjusted, only measuring will do that.
Might need a cam cover gasket, but that's it (aside from maybe a shim or two).

I would at least try cleaning all the connections in the coil supply circuit, and the coil mod would not hurt.

steell wrote:

Checking/adjusting the valves is not hard, and Z1 Enterprises has a few shims if you can't find them locally. No, a compression test won't tell you if the valve clearances need adjusted, only measuring will do that.
Might need a cam cover gasket, but that's it (aside from maybe a shim or two).

I would at least try cleaning all the connections in the coil supply circuit, and the coil mod would not hurt.

It's that cam cover gasket that is the problem. I had to make the one I have on now. Thats one of the reasons I'm not too anxious to do the valve adjustment. I was hoping to get a whole engine gasket set, when I break it down this winter. I did clean my connections and put dielectric grease on them also. So it sounds like the coil mod, is in my future. If I remember correctly the mod is written for 2 coils. Do you know what I need to do for only 1 coil? Or is there a link for the single coil configuration? Are there any aftermarket coils that can handle a lowered input voltage?
Thanks again.
BTW I've decided to be optomistic, I got insurance from progressive, $87, and am tagging it tomorrow.

Since I just bought another complete gasket set on eBay, I figure I can let go the NOS cam cover gasket I have (I think, need to check to make sure I have not used it). PM me if you are interested.

I don't believe there is any difference between one and two coils when doing the mod.

Thats really nice of you, Steell. I'll be pming you soon. Thanks for the offer.
I've printed the procedure for the coil mod, you're right, there really isn't any difference.
Thanks again
Ron