Check the simple things.

[KDIMD]

I have been having fuel issues for some time. First the bike would die when I hit around 150 kph. But would almost immediately start up again. A month later, the bike died on the way to work, a short 5 km ride at slow speeds. I would coast over, and cycle the reserve and pump would refill the bowls and I could ride til the bowls emptied. But on the ride home, no problems. I checked the sender, fuel light but thought it was the on reserve switch or maybe the fuel relay. Anyway, threw just about everything I could think of trying to find a solution. So I had a spare fuel pump and decided to change that as well. Took off the hose from the tank and noticed a cut at the fuel pump where the clamp had wore through the hose. Impossible to see unless your removing the fuel pump. I had a similar crack in the hose in the loop section and had told my mechanic to change them all but he didn't. Anyway, a short hose later and took her out and she really rips. I forgot how fast she was. Just wish I had more time to get out of town. Check those fuel lines if they are original.

BTW, I scored a new bike. Its a 2018 Softail Heritage Classic 114. Someone won it in a raffle at the casino and sold it straight away for 40% of MSRP, which here in the Philippines meant it was same price as I would have had to pay if shipped in from the USA. It will replace my Dyna Super Glide. I will have to admit that its a great handling bike for a Harley. The mono shock is years ahead of old models. Just waiting on some pipes as its quiet.

 

[Fire-medic]

Don't you have a supercharger and a great big tire on that bike? Your bike 'rips' more-than most VMaxes!

Glad you found the issue, and that it was something cheap to fix.

 

[MaxMidnight]

Many years ago a dealer that I used to visit had a vehicle in with a misfire.
As this car was still within its warranty period they ignored one of the basics.

Now, when most folk check plugs they hold them upside down don't they?
All checked out OK.

For whatever reason someone looked at the plugs with the electrodes facing downwards and noticed that the end of the ceramic insulator on one plug had developed a radial crack around it.
When installed in the motor this dropped down and shielded the central electrode.

Plug replaced and misfire gone.

AS you say, start with the basics first.

 

[dannymax]

That's an oddball one Steve!

I had sort of a similar issue with a VMax I was looking at to buy....it ran strong on the road but at idle it would start running rough, misfire, re-fire then run good again for a few seconds.

The guy said it was a plug fouling then clearing itself out....I thought no, I don't believe that's what it is.

Got home, pulled the carbs apart and the main bleed pipe in one carb wasn't screwed in, it would fall down in front of the main jet partially blocking fuel to that cylinder, then I guess a big burst of fuel from the re-fire would clear up for a bit.

Put about 10K miles on that bike then 4 or 5 years ago chopped it all down and it's been the carb rebuild test mule ever since....a great motor! :clapping:

 

[[email protected]]

At work, we have many trucks, heavy equipment, small engines, etc. Seems most repairs are simple things. The hard part is finding them!

We have a group of family and friends that ride ATV/UTV/Dirtbikes together. We go on a few trips a year. Stuff breaks on every trip. Typically multiple things.

Couple examples from the last 2 rides

1. Grizzly 450 ATV wont rev past 1/4 throttle. Sudden failure
Solution: Diaphragm cover screws fell out. Cover was there but loose. Cleaned diaphragm, installed screws. All good.

2. CR500 throttle moves as it should but engine is suddenly screaming WFO
Solution: Pull sub-frame, airbox, and silencer as a unit while on side of trail. See that a couple chunks broke off the slide and is preventing it from closing. Remove carb, clean, reinstall and ride it out of the woods. New slide needed but still rideable. Better than towing a bike through miles of trails.

3. Ancient Polaris ATV engine bogs above 1/4 throttle. Sudden failure
Solution: Carb vent tube melted against exhaust pipe. Cut tube back.