Strange behavior...

[BlueJ]

So over the past month or so, every once in a while while I'm zipping along, the motor just stops. No red light still have power, a blip of the starter or an easing of the clutch and it comes right back to life. It only happens on decel - could be at speed when I pull in the clutch and start braking, could be right as I come to a stop, but it's always on decel. And it always lights right back up again. This has spanned a couple tanks of gas, so it's probably not a plugged vent to the tank. And the 'lectrics are always still available so it's not my battery connection (although that's been checked and confirmed tight). Any ideas? Could it be that I need to clean my K&N's? How do you clean paper filters? Could it be float valve issues (but I haven't had the carbs open in months, and have been riding off and on all winter)? Early failure signs of the stock ignitor? Old plugs?

Thanks guys!

 

[CBJoe]

Does ever happen under engine braking (ie. when you're still at Higher RPMs)? Or only when you go from a high RPM to a Low RPM?

How low is your idle set?

Regards, Joe

 

[CBJoe]

Could also be out of sync carbs....

 

[buckstoy]

Have you balanced your carbs? Mine has been doing the same thing and I'm going to try the old carb balance...... On a completely seperate note, I've never had so much trouble reading on the internet as I did when I tried to read your post:cheers:

 

[BlueJ]

Not out of sync carbs - they are spot on (yes I do it myself). Idle right around 1000 RPM, I wondered if it might have been low idle speed but I cannot explain why it would happen - sort of like a candle going out??

Not really under engine braking, because in that case the clutch is to some extent out - usually only happens when clutch is fully in and revs are going down - not under load - when it happened today, I was going my usual lesiurely pace :motorbike2: and hauled in clutch in prep for a downshift and out it went, revs right down to zero, so I feathered the clutch out and it lit right up again (without me touching the starter - sort of like jump starting). That's what makes me think it's not electric.

Sorry about that slow reading problem. Too much beer??

 

[sweatmachine]

maybe a wet ignitor? You might just loosen that connection and slather some dielectric grease on it to eliminate that variable.

Also might pull the float bowls just to see if there's any crap in there. I just pulled mine and they were totally full of shit and were causing my bike to run funny.

 

[Speed3Chris]

Intermittent issues are the toughest to diagnose as you know because there is no blatant failure here. Aside from what the other guys mentioned, a general good rule, is PM stuff if not performed in a while is always a good starting point as PM needs to be done at some point anyway. Clean or replace air filter...and even gas filter if not done before. If mine, I would start with change and gap or at least gap and clean the plugs and check the ignitor gap and set it to low side of spec. Never a bad idea to pull the connectors apart and repack with di-electric as Sweat suggested. Check battery voltage both running and with the bike off after a day or so. These bikes don't charge under 1000 RPM so a mild bump in RPM is never a bad idea...maybe losing a bit of spark. Rectifier/regulator maybe slightly under charging overall....simple stuff first and good luck.

 

[cafenoir900]

Hmmm, does it only happen with use of the clutch? If so, might be in the clutch handle cut out switch. This is linked as well with the kickstand switch. I had a problem with the kickstand switch (would not idle well, and would cut out intermittently with the stand down) and just removed it, problem solved. Check the "safety" switch at the clutch handle and the related circuit.

 

[Texas94fs]

It probably just wants you to get off and to be ridden by your wife instead.


On a more serious note, the clutch relay sounds like that may be it. Especially if you are able to start the bike again with just letting the clutch out. I was under the impression that you coulnd't push start these bikes due to some interruptor or other thingamajig (bla bla bla insert interesting technical speak)

 

[Baltobonneville]

You can't push-start if the battery is dead, something to do with the ignition circuit. Otherwise, you can.

I don't see how the problem could be the clutch switch, because when you're riding, the system doesn't care if it's on or off. Right? And what is the "clutch relay", Texas?

Side stand switch? Somehow?

 

[BlueJ]

It has only happened with the clutch in. Although I usually remember to put the sidestand up before going 75 mph.

It is very infrequent - has happened once or twice sitting at a redlight, and a few times at speed (but then only on decel, not on the brief blip of the clutch as I accelerate).

I'll turn up the idle a touch, pull the float bowls, and either clean or replace the air filters and keep you all posted. Thanks!

It probably just wants you to get off and to be ridden by your wife instead.

No, she doesn't like riding my bike at all - she much prefers her own!!

 

[RICHW]

...a pesky loose wire in the key-ignition switch maybe?

 

[CBJoe]

I'm still voting on an Slow Jet / Idle Circuit Issue that hits when going from a high running rpm to nada with the clutch pulled in. Could be an electrical issue... but I would think that more random running scenarios would happen.

This is something that I have had happen to my bonnie when trying to ride when not warmed up all the way and no choke. Ie.. push off the choke when riding and it seems fine, but you pull the clutch and revs drop low and bike stalls.

How's your air filter(s)?

Joe

 

[cafenoir900]

I mention the kickstand switch because it is in the same "safety" circuit. Still sounds electrical to me, not fuel. Try over riding the clutch handle switch and see if it still happens.

 

[coopv2]

I also dont have a magic answer to your problem, But if it makes you feel better. I have noticed on throttle back off as I button off for a corner, I feel like I get fuel starvation for a second, and it seems to need a smidge more throttle to come back to life, but not cutting out like yours.
I say raise your float level just a little, and see what happens.
I think as your clutch is in and no forced momentum from the back wheel. there is brief second of fuel loss and she dies.
That or someone put a sock in your air intake. Do you live near sweatmachine? ;-)

 

[philodilemma]

Did you ever figure out what was wrong with your bike? I am having the same problem.

 

[Baltobonneville]

Someone on TRat just posted the same problem: Engine cuts out when he pulls in the clutch at speed (2007 carburetor model).

 

[coopv2]

THE SOLUTION TO THE PROBLEM IS..... faulty side stand switch. both the side stand switch and clutch switch have a black wire with a red stripe. and a ground wire, both switches go to ground, with only a twin wire circuit. I am sure if you start be replacing or checking the switch on the side stand. you will eliminate the problem.
The bike has a safe guard, that cuts ignition when the stand is down and the clutch is pulled in. has to be the side stand. as a faulty clutch switch would cut out the bike from starting.

 

[BlueJ]

The side stand switch is a nice theory, but I know my side stand is up when I'm whizzing down the road. And furthermore everytime it happens the starter works fine. I've only ridden twice since my post (pollen is killing me and I had to travel for work), but bumping the idle seems to have helped a bit.

 

[KingOfFleece]

I'd still switch the switch, so to speak. Electric issues have a strange way of acting that OFTEN defies a logical answer. The only way to know for sure it's not the side stand switch is to replace with a know good one. Much stranger things have happened with electrons....
I've often found that even if one part of a circuit works another may only work part of the time, even when that's not supposed to be possible. I'd also look for a worn wire and/or wire loom that makes contact when the cable is pulled which causes it to move slightly. It may be grounding out for a very short moment. These kinds of issues can sometimes be a real bugger to locate but as I mentioned, it seems often that it's something I thought I had already checked or was sure was ok....and then it's not.
Let us know how it all shakes out. And thanks for the button last year.