I've been lurking around here since around may. I purchased a yamoto 50
from raceway for my 7 year old daughter. Other than the brake light switch
failing in the first two weeks we had the machine it has been a very good machine.

The question now is how to get a little more grunt out of this machine. On a flat
run it goes way faster than I want her going, paced here at 25 mph. It was still pulling
so there was even more there. I turned the throttle screw in after that. Trying to get it
to climb a hill is another story. Is there anything that can be done
to remove some of the slippage from the transmisson?

I had her out yesterday and one of the hills we had to go up it just couldn't do it. With the throttle screw
all the way out the motor was revving for all it was worth but the atv wasn't moving. This was a hard
packed trail that was smooth. I do understand it is only 50cc so I am asking a lot.

I have pulled the exhaust pipe off. There seems to be no restrictor plate in it. At least not in the end
that bolts to the head. Since I am at 5100 feet. I did have to move the needle to its leanest setting.
It smoked like an over oiled two stroke until then. It is running fairly clean now. The plug is light gray.
If there are any other known restrictors hidding somewhere on the machine I'd like to know.

A larger machine really is not an option for a couple of more years. All the info I have found on our laws.
Lists the 50 as big as I can go right now and be legal. Though it is some what a gray area on whether
she can even be riding with me.

Robert

 

Since you don't want all of the top end that you have, and need more grunt on the bottom side. You can go with a different rear sprocket. Not sure where to get one, but it would fix your problem.

 

We're planning on putting a new sprocket on the back in the near future for the same reason. Ours will go up hills ok, but it does get stuck if he stops in the middle of the hill, then we have to give it a little push. I'm not sure where my husband found the sprocket though, I'll ask when he get's home.

 

I am hoping you found out where you bought the sprocket for the Yamoto 50cc,and how much of a difference it made.Also,on the list of atv's you own,it listed a Akuma 150cc-which you said was the biggest POS,What was wrong with the atv?(We were looking at one for our son) Thank's

 

I did find out where he got it, unfortunately it won't do you any good since he plucked it out of a pile his former boss had laying around. He has no idea what it came off of. The sprocket did help some, but not enough. My husband ended up pulling apart the tranny and tweaking it some.

As for the Akuma, we had **** poor luck. Everything that could go wrong, did. Fan busted off, swingarm bolt snapped, rocker-arm assembly seized, the list went on and on. There was a thread on Akuma's but I think it went poof as it got quite heated. I'd suggest looking around some more and see what else is out there, but that's just my opinion.

 

I should know today if i have found what fits for a front sprocket.
After doing some research I ordered a 12 tooth gear for a 98 honda XR70.
I compared the existing sprocket to yamaha sprockets and they do not fit.
The 12 is the smallest sprocket available. I'll post another reply once the part
shows up today.

 

The new sprocket showed up. It does fit. Of course the chain is a little to
long since I dropped two teeth. I would say the rear sprocket is probably
a honda piece also. The chain is a 420 chain so I would look for a rear sprocket
from a small honda using the 420.

The factory retaining plate for the sprocket did not fit. The bolt holes do not line
up. I used the cir-clip that came with the new piece.

 

How did your sprocket mod help out the little yamoto 50.

 

It's hard to tell overall. The weather has been so cold I'm hard pressed to get the
daughter out. I'm the only one crazy enough to ride.

The honda z50 sprocket fit without any problems. I believe they have 12 to 17 tooth
sprockets available. i used a 12. The first thing I ran into was the chain. The factory chain is 88 links.
I made a 86 link chain also. The 86 link one is to tight. There is no slack in it at all. The 88 link chain has
to much slack. The adjustment slots on the read axle are to short. I'm using the 88 since even with the slack it has
it is not so loose that it will pitch the chain.

As for how it runs. This little thing runs as strong as ever. The motor will rev up much easier now. With me on it.
It would bog down in our gravel driveway. I can get it going from a stop without any problems now. The final solution
is going to be finding a 50cc shifter motor. Having this one locked in 3rd or 4th gear just will not work in the long run.

 

Alright,
I ordered a 12 tooth front sprocket for a 1998 XR80. It was a perfect fit. I have a newer model Yamoto 50 with the better rear swingarm assembly. I had plenty of chain adjustment, and it worked out great. The change was just the amount I needed.
Thanks alot for the info.