250cc Jonway sounds like a Diesel Engine By drv1ru5 (Read 2,216 times)

[drv1ru5]

I have a Jonway 250cc scooter 172MM engine. So the prob is this, the bike was running strange and really started to have a Diesel Engine sound to it. I took it to my mechanic and at first we he thought it was a cracked air valve, but it turned out not to be. He adjusted the valves, inspected the rollers, blew out the carb, and cleaned the spark. The bike is running much better, but, we have no idea why there still that strange diesel engine sound, and the bike is running much hotter that it use to “top orange line before red”. Anyone have any idea what could be wrong? I have about 4,200 miles and I am using Amsoil scooter blend in the engine.

[speedracer]

The diesel engine sound was more then likely loose valves. Since it is now running good, your mechanic did something right to fix the problem. Running hot is not good at all. Is your fan kicking on at all? Have you checked the coolant level? Is there coolant in the over flow tank?

[yoster]

When I first started reading this I thought, ahh, valves! Then as I read more I thought.. wait, no, they checked it. Then I thought, something in the CVT! Wait no... lol

Looks like the mechanic checked all the primary culprits for a diesel sounding scooter. My next guess would be that something is hitting somewhere. I.e.: In my scooter, due to the way these little motors vibrate, something on the carb is hitting this piece of metal, SOMEWHERE (I've never been able to determine), and it always makes a fast rappity-tap tap sound. If I put my hand on it or brace it so there's less vibrating, the sound instantly goes away.

Any chance you could post up a vid so we could see/hear?

[yoster]

Oh yeah and welcome to Scooterdoc!

[drv1ru5]

I'll take a video with sound so all can hear and post it! it really does not sound like something rattling around, almost like a vacuum compression sound. Very much like a diesel engine would sound like.

Thanks all for responding, I am stumped!

[Alleyoop]

It could also be your Starter Clutch, they do make a racket because it is not disengageing. When you start the scoot does it ever KICKBACK on you when you press the start button?
Alleyoop

[drv1ru5]

what do you mean by kick back on me?

[speedracer]

Isn't his problem now running hot along with the diesel sound?

[drv1ru5]

yes, that is the issue. formost the diesel sound and that fact when I'm on the freeway it gets hot. on a side note, the fan does come on.

[sunlproblems]

check the waterpump it could have a bad bearing in it

[drv1ru5]

That could be a plan, does anyone have any pics or directions for the water pump?

[bhinch]

Just a note...check the center stand rubber wheel....it will touch the engine case and sound like you have a rod knocking....enjoy the ride.....thanks...

[hitmusicinc]

check the rubber intake manifold to see if it is cracked