Ahhh, I was wondering because the starter gear it self only spins when the starter motor is going. It would not probably keep up with the motor speed and it might not engage the clutch if it were not going fast enough.
This should be a low wear item that rarely needs replacing.
I had expected some real slop in the play on the rod journal, it moves a few thousandths of an inch and there is a little roughness in the bearing when I rolled it along the counter top, there was not anything absolutely horrible though like I expected.
I told Doug most of this when he picked it up but to refresh his memory and for the benefit of the readers I will try to summarize my experiences with that scooter. I'm not a newbee to motorcycles. Started with a Harley Topper in 1961 and have been riding for 52 years. I didn't count up but more that 20 cycles including 3 Harleys, several Yamahas and Hondas. Then about three years ago I bought my first Chinese scoot, a Znen ZN150T that I dearly loved but when we decided to go full time RVing I knew I needed a 250 and anything larger would too heavy to be practical to haul. (I'll soon post a picture of the way I haul my Reflex which I replaced the Jonway with,) I bought the scooter from Superior Power Sports in City of Industry CA. They assured me that it was a Rocketa MC250B not a Jonway YY250T. And showed on their web site that it had the Linhai engine. My son and I drove from Tucson to pick it up and guess what it was a YY250T. In less that a 1000 miles left fork leaked and they would only warranty it if I sent the old one back first. Bear in mind we are in an RV and move to a different place every week or so. So I bought the fork, they sent the wrong one and would not send the correct one until the wrong one got back to them. On top of that the front forks would bottom out on even a medium bump. At less that 2000 miles, right side leaked. I went to Honda and got seals for a Reflex, put the correct amount of in both sides and corrected the bottoming out problem. Then the Temperature gage went crazy when I was a long ways for home. I changed the temp sender twice but it was the gage. Then one of the screws on the back side of the variator worked out. I tried to replace it without an impact wrench. BIG mistake. Two variators later I bought a 24 volt impact and solved that problem. The starter relay stuck in the start position and ran the starter until the battery died. (you can see from about I replaced it with a Ford starter relay and used a horn relay to operate the Ford relay. Somewhere along the way I noticed a little noise and it gradually got louder. Several times I went over it with and engine stethoscope and never could determine the cause. Even removed the variator so knew it was in the engine but could not put my finger on the noise. It ran strong to the point that is sputtered and quit. You can see from the pictures and description that cylinder and valve train is in good shape. It was never low on oil, from 5000 on it never used any between changes, Of course I am curious to see what Doug finds. I can also assure that the Honda Reflex is superior in every way.
Last Edit: May 17, 2013 21:35:42 GMT -5 by skyrider
Skyrider, I am betting the noise you heard was the bearing on the crank end of the rod, it has a little roughness in it and that is all I have found, I also played with the oil pump and it seemed a bit rough when I rotated the shaft on it.
Also I have not found anything that looked like it was the source of all the metal pieces I found in it.
Well, the flywheel is locked in position with the key in the crank shaft, that key was fine. The metal might have been messing with things, may have got into the bearing on the rod and ruined it. I wish I had found something that looked like it was falling apart though, it would give me some piece of mind regarding all the metal flakes.
With that amount of metal debris that you found inside, you would think that it would be pretty obvious as to where the bad part was.
I have seen engines before having some little bits of metal on the filter screen from a oil change, where the factory didn't wash out the engine well before they finished assembling it. But never that much metal floating around inside before.
Check the camshaft chain drive unit on the engine. Maybe the tensioner or something caused it. The chain may have been loose and ate into the cylinder tunnel.
The cam is driven off a gear on the crank, it looks fine and I did not see any wearing in the passage cor the chain, it appeared pretty snug when I took it apart. I am really wondering if there was just some loose metal in there. The crank rod bearing and the oil pump are the only thing I have found that was rough.
Well I don't think it would be wise to use the oil pump or the crank. I already ordered a new starter clutch/gear because of the wear on that bearing and I could not find just the bearing. As I see it the parts are going to be about $250.00.
Then I have to fix a stupid mistake I made as well. I will post that later.
I hope your first guess at $300 did get it done. I just saw a Jonway 250cc engine rebuild kit for less than $150 w/free shipping. It is amazing how inexpensive parts for these little scoots are compared to the auto world.
Last Edit: Mar 6, 2014 16:16:44 GMT -5 by rockinez