Sudden loss of power and heavy vibration

[skids]

The ignition box, the pickup unit (including the vacuum advance and centrifugal weights etc) and the coils (3 ohm or 1.5 ohm) and the ballast resistor are all specific for the system. I would look for that 4RO box as a replacement. I just sold one this year for 50.00. In your case, because it seems you want the 81 system, you need it, You need the pickup assembly for the 81, the 3 ohm coils (check them), and if you have the older frame, bypass the ballast resistor. I am not sure that the ballast resistor would even have leads to the 4RO box but I would bypass it just in case.

If you want to use the older box, yes, you need the entire pickup assembly. Also if you have the older 1.5 ohm coils, use the ballast resistor.

[skids]

I zoomed-in on that board pic. That thing is completely separated all the way across on the right hand side! But I am sure you know that.

[motoman]

Hi motoman,

Would it be possible to install a mechanical advance mechanism on a '81 model and use a 2H7-10 ignition unit?

Yes, but some wiring changes will have to be done. Am no help with that, but there are a few more knowledgeable folks here that could be of help to make that change. IMO, the correct attack would be to plug'n'play the correct TCI. It's advancing set-up is better matched to the later model cam profiles, overlap time, duration etc..

[DiverRay]

Yes it would. If the '81 does NOT have the vacuum advance mechanism, that could be a minor problem. You would mostly notice a drop in fuel mileage.

[Phare Est]

I zoomed-in on that board pic. That thing is completely separated all the way across on the right hand side! But I am sure you know that.

The circuit board split pretty easily. I think the previous owner may have attempted to resolder the connections. I've had my '81 XS11LH for 2½ years and it's been causing me a few electrical issues, most notably a charging problem, and now this. I don't believe the PO had properly stored and maintained the bike over the years.

I've checked the ignition coils with an ohmmeter and they are both working fine (I have the 3 ohm coils). I will be purchasing a 4RO-10 ignition unit, since it's the easiest fix.

[DiverRay]

Check with andreasweiss. He has parts for these, and lives in Canada. He is close to the border so ships both ways without the usual hassle.

[Phare Est]

Check with andreasweiss. He has parts for these, and lives in Canada. He is close to the border so ships both ways without the usual hassle.

I was able to find a working 4R0-10 unit at a decent price. I should receive it within the next two weeks.

Thanks to everyone for the input! I'll keep you updated.

[Phare Est]

I received the ignition unit sooner than expected. All cylinders are now working properly and the bike has the same power and torque it had before the old IU failed ☺. The engine also runs much smoother. The bike still needs a carb synch, as it idles a bit erratically and it produces the occasional backfire. That being said, the problem is pretty much solved!

If my new IU were to fail, it will no doubt want to attempt a repair by resoldering the connections, since those TID 14-04 4RO-10 units are rather hard to find. Is this a difficult/delicate job?

[Phare Est]

If my new IU were to fail, it will no doubt want to attempt a repair by resoldering the connections, since those TID 14-04 4RO-10 units are rather hard to find. Is this a difficult/delicate job?

"I will no doubt want to attempt a repair..."

[DiverRay]

It's not that hard. Pull just the top cover and DO NOT try to remove the board! Take a soldering iron or gun, and heat each solder joint till it melts a little, then move on to the next. IF you can find some OLD solder, that has lead in it, use a little to help the flow. DO NOT USE LEAD FREE SOLDER!! It has a higher melting point, and can cause "solder wiskers" to form. This can lead to shorts on the board. There is a reason that lead free solder cannot be used in communications and space/aircraft applications.

[Phare Est]

Carb synch

I finally got down to synchronizing the carbs with a vacuum gauge kit. This was my first time attempting a carb synch. Although the bike now runs somewhat smoother, I still get backfire on deceleration. Is the engine running too lean or too rich ? Is is simply a matter of adjusting the idle mixtures screws on the carbs (which I haven't touched)? My XS11 is fitted with this aftermarket exhaust: http://www.nichecycle.com/ncs/catego...rformance.html. I'm quite sure there are no leaks at the gaskets. Also, there is white smoke coming out of the exhaust when I fire up the bike (especially on the right side). The smoke disappears after a few minutes. If I pull the choke out to the first position, the engine dies very quickly. How should I go about fine tuning the carbs? Thanks!

[Bonz]

White smoke, probably oil related. Valve guide seals could be wearing and as the bike sits between starts it allows oil into the combustion chamber.

Backfire on decel is usually lean, with those pipes I would expect that to be the case.

[DiverRay]

You WILL need to adjust the idle mixture, and then do the sync one more time.
For the idle mixture:
1. start at the left OR right carb, your choice.
2. When the engine is warm, and you have the fan blowing over it to keep it cool, adjust the idle mixture on the first carb until you get the idle as high as possible.
3. Move to the next carb in line and repeat. If the idle is above 1,400RPM, adjust down to about 1,000RPM before moving on.
4. Once all four carbs are done, re-adjust the sync.
If this dosn't help, you MAY need to adjust the jetting a little for the pipes. Do a search on "carb jetting" and you should find some of the old threads with the information you will need to make the proper adjustments and jet changes, if needed.

[Phare Est]

You WILL need to adjust the idle mixture, and then do the sync one more time.
For the idle mixture:
1. start at the left OR right carb, your choice.
2. When the engine is warm, and you have the fan blowing over it to keep it cool, adjust the idle mixture on the first carb until you get the idle as high as possible.
3. Move to the next carb in line and repeat. If the idle is above 1,400RPM, adjust down to about 1,000RPM before moving on.
4. Once all four carbs are done, re-adjust the sync.
If this dosn't help, you MAY need to adjust the jetting a little for the pipes. Do a search on "carb jetting" and you should find some of the old threads with the information you will need to make the proper adjustments and jet changes, if needed.

Hi DiverRay,

Thank you for the tips! Took me forever to do the carb synch, but it's finally done. I had to start by calibrating the vacuum gauges and synching the carbs one more time before moving on to the idle mixture screws. After adjusting the mixture screws, I synched the carbs again, just like you suggested. The bike was definitely running too lean, as it was difficult to fire up (in addition to it backfiring and having an erratic idle) and the headers were blueing. Had to shut the engine many times during the entire process to keep it from getting too hot (even though I had a fan cooling it the whole time). The bike now runs and idles well and the backfiring has been completely eliminated!

[DiverRay]

Hi DiverRay,
Thank you for the tips!

That's why we are here, to help each other. All I ask is to pass along things as you learn to the next person who needs help.
I actually did a carb sync last year in Colorado at the rally. Bike ran better once I got done with it, and I had 3phase and motoman to keep me from messing up! It's really a BIG difference in the way the bike runs once everything is correct, as opposed to just close.