[mshowe]

Owned my '83 since it was new.  Getting tired of not being able to ride it (reliably) for over 5 years.  So, after taking to a mechanic - where it performed almost flawlessly, I decided to remove the carbs myself. 

I've posted this before, but i'd lose a cylinder after doing a wheelie.  At first, I thought it was electrical.  I believe to have ruled that out, so what I believe is happening is float was/is getting stuck  -perhaps, in either the wheelie or as front tire came back down to earth.  I am attaching a couple of questions that perhaps could confirm that.  I found a piece of the float "Flaking" off on one side.

So, now that I have these puppies off, I suppose I should rebuild them?  Or should I just clean, put back together, and hope my problem is fixed.  Think it's ok to have that piece of the float "Flake off"?  I believe i've read that floats are very hard to come by??  I am not 100% confident doing it myself.  Any advice here (either encouraging me or offering to do it for me) is welcomed!

[Walt_M.]

I wouldn't be too worried about that little bit off the float as they are virtually impossible to come by. First question,  have you disconnected the rev limiter? It kills the front cylinder when it fails. If the answer is no, squirt some carb cleaner around and put them back. Now you will have to synchronize the carbs but you shouldn't have the dead cylinder problem.

[mshowe]

Thank you for your reply.

I have cut the revlimiter wire, sometime in the past, in an attempt to fix this problem.  It didn't change anything about my predicament.  Is your answer the same?  Think I should do some carburetor cleaner and put it back together then?

Do you think that flake could have hung the float up?

Thanks!

[fret not]

Highly unlikely for debris from the float to obstruct the float valve, as it would have to flow uphill to do that.  The important thing is to set the fuel level in the float chamber, and this can be checked with clear tubing attached to the drain vent and held up to the top of the carb  body.

[Walt_M.]

Since you have disconnected the rev limiter and you have the carburetors off and partly disassembled, go ahead and give them a thorough cleaning. Just be very careful. There are few replacement parts available if you break anything.

[Rikugun]

This reminds me of my brother's gas powered tree pruner. Sitting on the ground it starts and accepts the gas well. When you lift it up to cut a branch, the engine falters and dies.   

Just spraying some carb cleaner in the general vicinity will likely do little. On the other hand, to do a thorough cleaning and rebuild with no experience (I'm making an assumption based on the post title) may result in irreparable damage. Breaking a float pin carrier post for instance, is not uncommon when driving the pin free. I'd tread lightly here. If it runs well other than doing wheelies there is an obvious solution. If it is happening at other times, consider having the carbs professionally cleaned. Even then, YMMV dramatically depending on the experience of the person performing the work.

[mshowe]

I really appreciate all of the replies. 

Here's the good news, I was able to re-assemble everything and put the carbs back onto the bike and it started. 

The bad news, the problem still persists.  I am having a problem finding where the rear carb overflow hose attaches.  Not comforting having a hose dangling that used to be connected to something.  I must be blind.

If it ran ok when not doing a wheelie, I'd "not do wheelies".  Although, it doesn't.  In the past, when it happened to run correctly - I could initiate the problem by doing a wheelie.  I always thought it was electrical, especially after I put on a new R/R and Ricks/Stator and it ran like a top for a year or so.  There were a number of corroded connections, etc, that were remedied.   But then, after I took it into the shop (and it performed ok for them - and when I picked it up - sure enough it ran fine) after I got it back it didn't run for me.  At that time, I was getting fuel running out the overflow.  That's when I thought it had been a carb issue - and perhaps the overflow hose had been plugged or something.  I know, I am reaching.

I have never replaced the pickup coils, although I have an extra.  I am getting spark.  Should I test the pickups?   Can I test the pickups?

If anyone is close to NW Iowa, I'll trailer this puppy to you and pay you for your time. 

Thoughts?  Be nice.

[fret not]

Generally, if you are getting spark that isn't the problem.  Must have spark, compression, and fuel.  If you have all those things then it could be erratic delivery of spark (timing) or intermittent delivery of fuel.  Another possibility is a failing safety lock out switch on the side stand or clutch.

[Rikugun]

If it ran ok when not doing a wheelie, I'd "not do wheelies".  Although, it doesn't.  In the past, when it happened to run correctly - I could initiate the problem by doing a wheelie.

The problem was described as having ONLY happened when the bike was doing a wheelie. Now we know it happened at other times. This is helpful but still not much to go on. Since intermittent problems are notoriously difficult to diagnose, take a step back and describe all the conditions under which it occurs.

What lead you to think doing a wheelie would initiate the problem or was that happenstance? Is it hot or cold out when it happens? Is the engine hot or cold? With tank full or not? Any non-stock electrical accessories on at the time? Does it idle when acting up? What are the symptoms exactly and do they vary? How long before it's running better again? Does that recovery time vary? Did it ever happen prior to the electrical work? List all the work performed thus far to correct the issue and how confident are you that work was performed correctly?

[mshowe]

The times and which this has occurred has changed a bit over time.  When it started, several years ago, it would come and go.  There's no correlation to whether it's cold/warm or how long it's been running.

The fact that when it would run fine, and a wheelie (which we can all agree causes a change in the bikes attitude and shaking to the entire bike when the front wheel settles back down), shouldn't necessarily confuse us of the root problem.  The problem would be "in waiting" regardless of how it occurs.  I suppose it could occur going over a very rough railroad track.

This is the way the bike is all of the time, now.  I couldn't believe it when I did take it into the shop last year and he said it ran fine.  I thought, "Well, he doesn't really know how it's supposed to run I guess".  I went up there (40 minutes away), and sure enough, it ran fine.  I am tempted to load it into the truck and drive it around - if one believes in gremlins. 

It does have spark, it has new gas and appears to be getting gas, seems to have compression - although I don't have a method of checking how much.  I think I'll take it back into that mechanic, who seems pretty accustomed to working on older stuff - although he said he's never worked on a vision.  I sort of trust his depth of experience. 

I am going to try and add some video.  Thanks for everyone's comments.  They are appreciated.

Here is a video of a start.  It's been setting 1 or two days. 

https://www.facebook.com/seanh.rgi/videos/10207972694208479/

[Rikugun]

I just watched the video and would agree it sounds like running on one cylinder. Do the test again and from the time it starts, feel the front and rear exhausts close to the head. It's important now to find out which one isn't running. Does one stay cold while the other gradually gets warm then hot? Or, do they both get temperature but one significantly more than the other indicating one running and the other intermittent.

The more information you can supply your technician, the better armed he'll be to diagnose the problem.

What makes you think the offending cylinder has spark under these conditions? If you can prove it does then it's likely fuel. If not, then ignition is also a culprit. How long before it runs good again? Does it come back suddenly or gradual?

[mshowe]

I appears to be the front cylinder not "working".  I can remove the plug wire from the front and back.  It runs the same (as when both plug wires are on) - after removing the front wire.  When I remove the rear wire, it doesn't start.

To answer your prior question: it never starts running correctly.

It appears the front cylinder is getting spark by holding spark plug against cylinder and turning it over. 

when looking down at the cylinders with breather off, you can pump the throttle and it appears to shoot gas into the cylinder.

so, because cutting the revlimiter wire (which I did) - deals with the front cylinder - I am planning to revisit that wire and make sure I have the black with yellow tracer cut.  I may try re-connecting.  It's probably not as simple as it having spark on the front cylinder negate that it could be revlimiter wire?  If that makes sense.

Thoughts?

[Walt_M.]

It is not the rev limiter. That kills the spark to the front cylinder and you said you have spark. You said you can see gas when you work the throttle. That is from the accelerator pump and independent of jetting. I think you have some crud in your pilot or main or both. Just for grins though, have you ever changed your sparkplug leads and caps, try swapping coils. Sometimes a little spark in open air is not enough to fire in the cylinder.

[mshowe]

Thanks for your reply.  Through the years, I've accumulated (I suspect like many of you) some extra parts.  Last year, or the year before, I did pickup some used coils and wires.  I replaced them both in an attempt to fix this problem.  The behavior was the same.

Since I've already had the carburetors off - I guess I could do it again, how successful - ya think -  would I be at identifying and cleaning the pilot, main - or both?  Or, does that require a rebuild kit?  Would I be able to visually see the blockage?

I did run some carb cleaner through what I could see.  That didn't change the behavior, but I really don't know what I am doing.  Having said that, I don't think I did any harm either as I am pretty careful.

What about vacuum?  Could I have a blockage that would cause the same affect?

Thanks again for the advice!

[fret not]

Is the fuel pump healthy?

It may seem daunting to take the carbs apart for the first time but I suspect this may be where your problem lies.  The jets have rather small orifices and it doesn't take much to block them.

Be very careful disassembling the threaded parts from the carb bodies, as sometimes they get frozen together.  If you break off a jet in the removal process you can pretty well scrap that carb body.  I have a couple sets of '82 carbs that have broken jets, and I thought I was being careful. 

[Prophet Of Doom]

You need to zone in on the problem else you will just run round in circles.


Do you have a spare TCI? Swap it over.  Same problem? it's not the TCI
Now swap the TCI inputs AND outputs left to right.  Same problem it's carbs.  Problem moves to the other cylinder it's electrical.

[mshowe]

I do have a couple of TCI's.  Same results.  I don't understand "Now swap the TCI inputs AND outputs left to right".

As always, I appreciate everyone's input!

[QBS]

Just viewed the video.  Reminds me of dirty carbs.  A blocked main jet or two, would make it run like the video.  Starts and runs only on the low speed circuit.   Again, which cylinder is running cold or cool to the touch?

If you decide to clean the carbs: the floats do not get disturbed with jet removal and, if I'm correct, the carb top can be safely ultrasonically cleaned with the float in place.  Your situation may provide you an opportunity to re jet the carbs and get desirable drivability benefits.

[mshowe]

Ok gents.  According to the picture in http://ridersofvision.net/rovforum/index.php?topic=8633.0

I removed the "Main Jet" (easiest to get to now that carbs are back on).  When I remove the front screw, gas pours out.  When I remove the rear screw, some weeping but not pouring.  Normal behavior?  I had pet cock in both on and prim positions with same behavior.

Now what?

[QBS]

No.  Sounds like a fuel delivery problem in the rear carb, possibly float valve related.