Last ditch effort before taking it to the stealership...
 

Hello everyone,

I recently gained back the motivation to fix my bike before surrendering and taking it to the dealership. The problem arose after installing my MCCT over the summer. After putting everything back together the following happened:

• Starts and idles just fine
• After the temperature gauge hits middle the bike GRADUALLY starts dying
• As the bike is dying you can hear little 'clicks'
• It will start dropping revs at an increasing rate and eventually it will drop so far that it completely dies
• After letting it cool down it will start up again just fine
• This happens both with and without riding the bike

I started this thread a while back and no conclusion was made. I've tore everything apart a few times and made sure my timing was right and everything was put together correctly. Yes, my petcock vacuum line is plugged in the back and my carbs are synced.

I've spent the last hour or so diving into threads and have come up with a list of some possible causes for my problem:

• Kickstand switch (as the exhaust heats up it opens the switch and kills the bike, cooling it down re-closes it)
• Vapor lock (I'm going to get a second key tomorrow to test this theory)
• Petcock diaphragm
• Bad gas/water in tank
• Dirty Carbs (needle valves)
• Ignition Coils

I'm asking for some help from you smart people to confirm/disprove my theories and hopefully come up with some more. I understand most of these are easy to test, I'm just looking for some direction and advise. I'm planning on updating the thread as I start knocking through these theories.

Kick stand switch would be more abrupt on/off if it were opening. I think you can jumper it to bypass the switch and/or test the switch with a multimeter when it's cool and hot.

2nd key OR unbolt the gas fill to ensure equal pressure on the tank.

Petcock diaphragm could be tested with tank off and applying suction to see if it opens and closes properly.

I think a bad R/R would kill the battery and it wouldn't start after a few start/stops.

A question of bad gas/water is easily remedied.

Usually bad battery is manifest in attempting to turn the starter motor, as in, it won't.

Needle valve(s) may be sticking due to fouling on it or on float arm. IF the fuel can't fill the bowl fast enough, then the engine will run leaner and leaner and drop revs until the F/A ratio can't support combustion. Sometimes fuel system cleaner can clear light fouling pretty quickly, but heavier deposits require at least pulling off the bowl and breaking out the q-tips.

Sometimes coils and/or spark plug wires can create electrical opens when hot, then act fine when cool.

Good luck, and let us know how it goes. :)

Thanks for the input ion!

That's what I was sort out thinking. But I figured it would be easy enough to bypass it and rule it out.

Good idea! I'll give that a try.

True. It definitely doesn't have a problem starting after it cools. Could probably rule this one out.

As a first order of business I was going to drain the entire tank and start with fresh gas; who knows how old the gas in the tank is.

I hadn't thought of that. I still have yet to pull a part my carbs so I'll have to read up a bit. As I start ruling some of these theories out I'll definitely consider this!

Another good idea. I'll add it to the list!

Just to emphasize this point; I didn't have this problem until I replace my CCTs and put everything back together. The bike was running just fine both all of that. So this is either a big coincidence or I did something wrong in the process...just something to think about...

I just replaced the CCTs with MCCT design myself. I think if you got the tension on them even remotely close to spec, the engine would run fine, or maybe have a constant chain slap sound, but not die. To replace the CCTs, though, other things were moved around and disconnected/re-connected, and a flaw may have developed there. For instance, maybe moving a plug wire caused a fracture to develop in the conductor, which when cool works fine, but opens when hot.

The symptoms point at something causing both cylinders to lose combustion, and not one firing fine while the other dies out. I'm thinking it's a fueling issue, and I'd check out the gas and petcock situation first.

Long shot,

Check the dreaded plastic choke fittings aren't broken or cracked.

Just a thought !

Pinched fuel tank vent hose? Easy to check just try blowing through it.

What about the pvlir or whatever vacuum hose onto the fuel tank? Do the test by putting a hose on the vacuum part of petcock and supplying vacuum by mitivac or by mouth to see if fuel flows.

What if the CCT is holding the chain way too tight.? It would get tighter when warm and cause issues maybe?

I had the no restart when hot that had the sidestand switch as the issue. I would not overlook the choke fittings either. They break if you think about them wrong and would cause issues.

I would not suspect carbs unless you rebuilt them at the same time as ccts (that would be a wrong thing to do).

Hey smokinjoe,

When I go to drain the tank I was going to check the vacuum at the petcock.

I don't think the CCTs are too tight. I messed with the tightness a few times and nothing changed.

I didn't rebuild my carbs.

Well, you are half checking that you are getting vacuum but half checking that the petcock flows fuel when vac is applied.

You may have connected the vac hose to the superfluous nipple on the petcock. In this way, the bike isn't dying due to warming up, but due to fuel starvation.

It just happens to be getting warm as it runs dry of fuel.

Looking through the troubleshooting section of the service manual, most has been covered here. Re-routing the choke cables when re-assembling was kind of a PITA for me, so make sure the choke is functioning properly. Also, I thought my carbs were seated then gave them a hard wiggle to find out they weren't. An air leak around the insulator/boot would cause the motor to run and warm up, then die.

Get some WD40 or such and start the engine.

Spray the fluid onto and around the intake rubbers/ carbs and see if there is an air leak.

Might help you !

Don't do it. You can get this sorted out. It seems clear (to me) that it's an air/fuel problem. Do as others have suggested. Don't assume.

Just to fill in the blanks. If you spray wd40 and it gets sucked into a leak (like a carb boot, etc) it will change the way the motor runs or stall it.

Simply spraying it wont help, you must observe the result.

Alright. So I finally go found some times to work on it. Below is a list of everything I did:

1. Made sure the bike started before diving into anything
2. Took off the tank and blew through the vapor hose. Air passed through it no problem.
3. Took off my air box and tighened the carb boots. They weren't loose but I tightened them up anyways.
4. Unplugged the sensor on the carbs and inpected it (not sure what the sensor it). It looked fine.
5. Drained my tank completely and filled it with new gas
6. Disassembled by petcock to inpect the diaphram. No cracks ot tears.
7. Applied vaccum to the petcock to make sure fuel flow out of it

And after all of that...THE BIKE RUNS! :D Its a miracle! I have no idea what ended up fixing it but one of the things above did the trick. The bike is having a bit of a rough idle (going between 1250 and 1500) and I'm getting the occasional carb farts (even though my carbs are perfectly synced. But at least its running! Any suggestions on how to address the carb farts?

I shoulda mentioned to avoid this in the future install some fuel filters. You coulda had bad gas.

Or the vacuum on the wrong petcock nipple. (sorry, those are correct terms)

You said you unplugged the sensor on the carbs. It's TPS and have to be positioned carefully. If you moved it then it can cause wrong mixture.

Well, it's always a mystery when you do a bunch of things at once, but it's a lot more efficient when you have the tank off to poke at multiple possibilities. I did the same yesterday getting a leaf blower working. Now if you simply unplugged/re-plugged the Throttle Position Sensor (located on rear carb) and didn't unscrew it and turn it any, then it should be close to fine. I'd say for the rough running, try running a tank of fuel system cleaner through it (my favorite is Sea Foam), then go from there. If the bike sat for a while and got the carbs gummed up but still runs, usually that will clear up with a chemical cleaning and running.

The TPS won't cause the issue that were described.

You can unplug the TPS and the bike will run just fine, though a bit down on power as the ECU goes to the default map.

Sounds like bad fuel but who knows for sure.

Glad you got it sorted.
I had the same issue when I rebuilt mine. I think my petcock wasn't on all the way.

from JUST the above I'd guess the MCCT are adjusted too tight..Simple to rule out, reinstall the ACCTs.... double, no TRIPLE check cam timing, have a second person not previously involved in the task read the timing check procedure and check for you.

Have them READ the procedure and you check.

More times then I can remember, I have seen a home wrench perform the task wrong, and then when told to recheck the work, checked it again using the same WRONG process, not because of a missed step, but a misunderstanding of the step or observation
So of course on recheck they did it exactly the same WRONG way. Not saying that is your issue, but again, simple to rule out, have a helper check.

I wanted to make a quick update on this old thread. It turned out that the after everything I did above the bike still didn't run; it would continue to die as it heated up. But, 7 months later, I'm happy to announce that it is officially fixed; for good this time. I had given up and was days away from taking my bike into the shop when I figured out the problem; sort of by accident. My father and I were working on our project bike and looked up how to test a pickup coil. The video we found happened to outline EXACTLY what my problem was: runs fine cold, dies as it heats up. So, I replaced my ignition pulse generator and...well...it was better but not fully fixed. So, sort of a shot in the dark, I decided to replace my front ignition coil and VAULA! It rides like a dream now! I rode over 100 miles today and it never died! I was too busy chasing what I did wrong in my MCCT install that I didn't even consider that it could be something completely different. It was just unfortunate that it decided to crap out right after my MCCT install. So, I hope this helps someone in the future. Here's a tribute photo of my black beauty.

glad to see a happy ending

Vaula?!

:confused:

;)

Glad to hear you're up and running again though!

Teamwork!