Motorcycle Forum banner

1 - 19 of 19 Posts

·
Registered
Joined
·
30 Posts
Discussion Starter #1
Hey Folks,

06 m50 33,500 miles had since new. Never ANY problems till this weird one. Starts up and idles fine , as she warms and idles down slight miss from front jug(I think), after fully warm 15-25 miles when you stop at a light the miss starts, engine slows and stalls. It will start right up with a bit of open throttle and a bit of stutter almost as if she's loaded up. When driving she's FINE I've: replaced plugs, adjusted valves(side note all valves were "tight" no clearance at all) checked for FI codes (none) checked TPS(fine) and added Techron FI cleaner to fuel. In short, HELP!!!!

thanks
Joe
 

·
Super Moderator
Joined
·
12,241 Posts
If there is an idle speed adjustment, be sure it is not set too low.

But this can be a sign of a weak fuel pump OR a bad tank vent making a vacuum in the tank.

If it is too lean when this happens, it could be an intake manifold or air box leak.

Long shot: Battery going bad or loose battery connection.
 

·
Registered
Joined
·
30 Posts
Discussion Starter #6
Aussie Steve:

Plugs were a nice tan as they should be ,that's why this is driving me bonkers!!!
 

·
Registered
Joined
·
6,768 Posts
Intermittent electrical fault? Maybe the ECU is on its way out?? It may be the fault is with the front cylinder only and one isnt enough to keep it idling. Check the plug caps/cables and coils...esp the cap to cable and cable to coil connections
 

·
Registered
Joined
·
30 Posts
Discussion Starter #10
I think you may have something here ,Steve! gonna check all the electrical,intermittent faults are hard to find .thanks
 

·
Registered
Joined
·
30 Posts
Discussion Starter #13
Hey Guys

I think it is solved (HOPE it is ) A DIRTY INJECTOR was the cause , A mechanic friend took the injector out cleaned it then put it back in with a little trick : he put straight Techron in the fuel hose for a shot of cleaner when first started back up. Seems OK for now

thanks for the replies to all!
 

·
Registered
Joined
·
6,768 Posts
I always run some fuel system cleaner through my bikes every now and then to prevent this and, more importantly, to prevent the fuel pump filters clogging up... touch wood haven't had any problems to date...having said that I do have a tendency to throw my bikes down the road before they get to any mileage where these sorts of problems can arise...hahaha
 

·
Registered
Joined
·
18 Posts
I had very similar symptoms and the cause was the TPS (on m50 and my vstrom). They seem ok when cold, and when tested but after riding and when the throttle body gets heat soaked, they fail. I know this is an old post but others probably will have this issue. It is an expensive fix at over 140 bucks but this completely fixed this problem for me.

I experienced stalls on return to idle while slowing at a light, backfiring, misfiring, severely rich smelling exhaust, drastically decreased fuel economy, difficulty starting unless WOT. It also seemed to run OK when on the freeway or when off idle. It didn't start off really bad or happening often, this issue gradually got worse over time so if some of your conditions match up, this would be a quick fix.

Also the newer bikes with a cat and a o2 sensor might react differently. Since the older systems have to guess at how rich the exhaust is, I'm guessing they will react worse, at least in regards to the rich condition.


Hey Folks,

06 m50 33,500 miles had since new. Never ANY problems till this weird one. Starts up and idles fine , as she warms and idles down slight miss from front jug(I think), after fully warm 15-25 miles when you stop at a light the miss starts, engine slows and stalls. It will start right up with a bit of open throttle and a bit of stutter almost as if she's loaded up. When driving she's FINE I've: replaced plugs, adjusted valves(side note all valves were "tight" no clearance at all) checked for FI codes (none) checked TPS(fine) and added Techron FI cleaner to fuel. In short, HELP!!!!

thanks
Joe
 

·
Registered
Joined
·
30 Posts
Discussion Starter #18
Hey Logic,

Thanks for the input. I STILL have the problem. Today (8/30) went for a ride and it did it! I think you are on to something with the TPS. It's not setting a code so I've been hesitant to drop the $140 on the sensor. I've got a goofy idea though: since it is a potentiometer it might be dirty the way a volume control gets scratchy . Wonder what would happen if I sprayed it with electrical contact cleaner? Again Freeway speeds (70/80 mph) fine. Come to a stop idle then stumble and stall if I don't blip the throttle. Also will stumble if you give it WOT quickly in neutral or open throttle wide in a semi-lugging roll-on
 

·
Registered
Joined
·
30 Posts
Discussion Starter #19
Ok Folks,

I don't know if anyone is following this post but, I HAVE solved my problem! It was a bad ignition coil. It DID NOT test bad with the ohm meter but when hot must have been misbehaving. So I am one happy camper once again, in love with my m50. A side note, when I first replaced the coils the stalling ceased but I STILL had a hesitation under load. I took a chance (which is pretty much how did this entire repair BTW) and put new spark plugs ,Bingo no hesitation. My theory : the underperforming coil messed up the plugs. So after 3years and many dead ends (including $400 worth of injectors) I'm good. Just posting so maybe it could help someone else. Safe Riding . Joe
 
1 - 19 of 19 Posts
Top