Stuttering while accelerating?

[Graman]

Thanks guys. I couple of months ago I did change both the plug wires and the coil plug contacts. The plug caps are new NGK installed last year. I'm curious about the kill switch circuit. What solenoid were you referring to where I should check the voltage?

[bikerphil]

Starter solenoid under the right plastic side cover. Just touch the + test lead to the red/wht solder joint which is exposed.

[motoman]

Thanks guys. I couple of months ago I did change both the plug wires and the coil plug contacts. The plug caps are new NGK installed last year. I'm curious about the kill switch circuit. What solenoid were you referring to where I should check the voltage?

Kill switch COMPLETES the primary circuit. Plug-in for that I think would be same location on your 79 as 80-81's. If so, its along top right of frame under tank....someone'll maybe chime in as to the two wire color code of that plug.....should be easy as it the only on in that kinda centered location. Key-on voltage drop(compared to key-on batt. voltage) across that two wire plug-in is either connection there itself(unlikely, but should be checked), kill switch(most likely), ignition switch contacts or both.

[Graman]

Thanks guys. You definitely have me thinking. I am going to check this out for sure. Just after I got the bike 5 years ago I installed a hidden kill switch on the bike. Just for anti theft reasons. I live in an apartment building and I park my bike in the underground parking. Break ins are fairly common. I used a common 15 amp toggle switch and tapped into the main ignition line at the fuse box. It's very possible that the contacts in the switch may have some corrosion even though it seems to work fine. I really never use the kill switch on the handle bars. Except when one of my friends turns it to the off position just to screw with me. The other thing to mention is that about a year ago my ignition switch started to act up. Especially in the cold weather. I would turn it to the on position to start the bike and nothing would happen. I had to turn it on and off a couple of times to get the bike to start. I sprayed some contact cleaner into it and seemed to solve the problem. It has never acted up on me since. I am definitely going to check those voltages and connections as you guys suggest. I am going to remove that kill switch and put the connections back where they belong. I want to make sure everything is good with the electrical before targeting the carbs. Again.

[DiverRay]

The handlebar kill switch is just about to go. They are ALL old, and the plastics give out. I have three at home that have done that. The good news, you can get a new handlebar switch set from mikesxs.com. all you need to do is change out the connectors. For your bike, order the one for the 650 special, as it has the longer wires. If he now carries the xs11 version, with correct connectors, you can go that way.

[CaptonZap]

I am going to remove that kill switch and put the connections back where they belong. I want to make sure everything is good with the electrical before targeting the carbs. Again.

Since you sound like you are conversant with electronic components, I would suggest that you take apart the ignition switch and refresh the contacts that are inside. It is a relatively straight forward job, and will give you some piece of mind in the future. There are some components that will want to spring out at you, so do it over a big towel, an uncluttered floor, and be careful.

CZ

ps I soldered the pickup coil wires on my G, about 8000 miles ago, and no problems so far. The point is that the solder joint should not be subjected to flexing, so bear that in mind. (Think shrink wrap, times two)

[Graman]

Thanks CaptonZap. I'm going to take your advise. I thought about taking it out and replacing it when it acted up the first time. It looks like there are a number of aftermarket replacements not too steep in price available on the web but I'm going to take it out and take it apart. Shine up the contacts and give it a clean. Whether it's the cause of my current issue or not it's probably good preventative maintenance. Going to remove my homemade hidden kill switch and check some voltages and connections tomorrow.

[3Phase]

Cap'n: Good work on the pickup coil splice!


Graman,

You don't have to take anything apart, you can check the voltage for the entire ignition circuit by measuring the voltage at the Red/White wire on the Starter solenoid.

The Ignition circuit makes a complete loop from the 10A Ignition fuse to the Starter solenoid, that's why the Start button won't work if someone flips the kill switch.

10A fuse ->
handlebar killswitch ->
the ignition coils ->
the TCI ->
tadah! back down to the Starter solenoid.

You can find the voltage drop for the Ignition circuit by measuring the voltages at the 10A Ignition fuse and at the Red/White wire on the solenoid, then subtract to find the difference.

OR

Measure the drop directly by putting the Red probe on the 10A fuse and the Black probe on the Red/White wire on the Starter solenoid.

Either way, if the result is more than half a volt then something is wrong and you need to go through the Ignition circuit.

Have fun!

[Graman]

OK. I had a chance to check those voltages today and they look good. Battery is probably a bit low. I haven't been riding it too far lately. I've been recovering from a lower back injury and my doctor told me to stay off the bike. Didn't work.

With just the key in the on position I got :
11.23 V @ the ignition fuse,
11.22 V @ the starter solenoid terminal.
A drop of only .01 Vdc. Looks good.

[motoman]

OK. I had a chance to check those voltages today and they look good. Battery is probably a bit low. I haven't been riding it too far lately. I've been recovering from a lower back injury and my doctor told me to stay off the bike. Didn't work.

With just the key in the on position I got :
11.23 V @ the ignition fuse,
11.22 V @ the starter solenoid terminal.
A drop of only .01 Vdc. Looks good.

That's good!.....prim. ignition looks okay.......but question secondary ign. system, voltage TO coils, etc..

[CaptonZap]

Not probably, definitely IS, low. At that charge, the plates are starting to sulfate.
Put a 1 amp charger on it, after checking the water level, and remove the charger at 12.75 V or there abouts.
A battery can be left at 12.5 to 12.65 volts indefinitely without harm. Anything above or below will cause problems.

CZ

ps A Variac on an old time charger can be used to get 12.5+/- Volts for long term storage.

[Graman]

I'm not too worried about the battery. It was brand new last fall. The charging voltage checked good at that time. I think it's a little low because I've been starting it a lot and idling it for long periods of time but not really riding it more than a couple of blocks to a friends place to work on it. I think I need to take it out for a good ride to get the battery voltage up but my sore back has limited me for the last 6 weeks or so. I do have a small automatic 1 amp charger that I use in the winter but I usually don't bother in the warmer weather. It always starts right away.
I did replace the ignition coils a couple of years ago and recently the wires and plug caps. I was getting a real week spark from the originals so I replaced them with the 3ohm Dyna coils. They give out a nice bright spark. Much stronger than the 35 year old stock ones.
I still want to do the valve clearances. I've never done it in the 5 years I've owned the bike and don't know if they were ever done by the previous owner. As advised in previous posts I am going to do this before I do anything else. I have had a problem finding a local source for the shims but haven't had much luck. I found 1 Yamaha shop not too far away that has some. I have to know what size I need before they can tell me if they have them. They won't trade them and want $10 each for them. The problem is I can't work on it at the apartment building where I live. I have to take it to a friends place where he lets me use his garage while his wife is at work and he enjoys helping me. I can't leave the bike sitting in his garage for days while I wait for parts to be ordered. I have to be able to complete the service in 1 day. This makes it difficult. I could take it a shop and have it done for around $200 but I can't really afford that and I hate to pay someone to do something I can do myself. I am going to check some of the local Honda shops. I believe they used the same size shims on there earlier CB models.

Sorry for going on so long.

[DiverRay]

I think it's the smaller Kawasaki's that use the same shim size. I ordered some online about 6 months ago, at about $5 each.
One thing to do is take it over to your friends house, let it cool a bit, then measure all the valves. Once you have the start, pull the cams and look at all the shims, and write down a chart with the "start" size. You can then button it back up, and using the chart figure out what can be swapped, and what you need to buy. Yes, that will be twice to complete the job, but you will then know what you have, what you need, and more importantly where you are for the future.
Here is the link to a good tutorial from Steve: http://www.xs11.com/forum/showthread.php?t=35434 Just checked, shims are 29mm! Be careful, as some Suzuki's are 29.5mm, and look like they will fit, but don't.

[Graman]

Thanks DiverRay. Great tutorial. I have it bookmarked. Your advise is good and I will probably end up doing that way. I wanted to avoid taking those valve covers off twice. Maybe I will get away with reusing the original gasket the first time and use silicone gasket maker when I'm finished the job. I do have the Motion Pro tool but maybe removing the cams is the better way to go. At least the first time to get all the sizes currently installed.

[motoman]

All excellent advice from DiverRay. Something to ponder.....your coil change was all good, but not a 'magic wand' if voltage TO coils is low. That in itself WILL eventually damage the coils. That is why I suggested checking voltage TO coils.....that it be same as batt. voltage, key on.