I'll make a different assessment. That looks as though the bolt was overtightened. Did you take the clutch cover off of there? There is some sort of make-a-gasket ooze coming out of there.

 

No, the clutch cover has never been off and the motor has never been apart. The previous owner didn't know how to turn a wrench, he would never have attempted something like that.



It was fine until it kicked back last night. I am absolutely certain that this happened when the kick back occurred.

I'll make a different assessment. That looks as though the bolt was overtightened. Did you take the clutch cover off of there? There is some sort of make-a-gasket ooze coming out of there.

 

if not him, someone else, because i agree with fatcaaat that motor has definitly been taken apart, including the cases being split you can see the yamabond or grey RTV seeping through where the cases meet. It could be from over tightened bolts and then the addition of kicking it over. 2 questions, can you tip the engine up to see if oil would leak out, and does it still kick over. If it still kicks over, and no oil is leaking, id just run it as that crack would only be affecting that bolt and nothing else.

 

YEA the cases have been split. That GREY looking stuff thats hard is yamabond or some other type of liquid gasket. Stock they dont use any liquid gasket in factory JUST paper gasket. That engine has been apart somewhere in its life.. Look you can see some of it hardened down the center.. I have no doubt it did it on kickback but there is something fishy cause the engine has been apart before...

 

Actually I have seen a few of the YX engines with the sealer on them, they seem to be the engines that were "upgraded " after they had been assembled the first time from a secondary "factory" .

Remember there were thousands of these engine built before the

"upgraded" case came out, so they hand the stock on hand upgraded.



This failure in nothing new , just rarer than the early ones.

 

It will turn over, but the transmission is not wanting to shift. It is either stuck in neutral or between gears. Something is boogered up inside, it definitely has to come apart.

if not him, someone else, because i agree with fatcaaat that motor has definitly been taken apart, including the cases being split you can see the yamabond or grey RTV seeping through where the cases meet. It could be from over tightened bolts and then the addition of kicking it over. 2 questions, can you tip the engine up to see if oil would leak out, and does it still kick over. If it still kicks over, and no oil is leaking, id just run it as that crack would only be affecting that bolt and nothing else.

 

wanna sell it ?

 

the yx repair kit will fix that motor with improved case and gears



Repair Kit for YX 160/150 case - Pit Bike Engine Parts - Parts & Kits ZS 155cc & YX160 - Repair Kit for YX 160/150 case - TBolt USA, LLC

 

i just bought a second hand yx160 with this same problem.. not even 6 tanks of fuel old..

problem is nothing new but like already said just very few seen these days..



it would be interesting to see what center case it has.

when you pull it apart can you post pics please

 

Pictures

The right half center case is majorly hosed. It cracked like a saltine cracker. It is a little hard to see it all in the picture, but there are cracks running all over in the back section of the case. Sh!t.



The repair kit in Tbolts reply looks like it is the same case, I thought it wasn't until I figured out his picture is the inside of the case. If the transmission gears are not buggered up, I may only need the case half itself. Anyone know if the case half is available by itself?



Thanks for the replies.



Chuck

i just bought a second hand yx160 with this same problem.. not even 6 tanks of fuel old..

problem is nothing new but like already said just very few seen these days..



it would be interesting to see what center case it has.

when you pull it apart can you post pics please

 

Re: Pictures

The right half center case is majorly hosed. It cracked like a saltine cracker. It is a little hard to see it all in the picture, but there are cracks running all over in the back section of the case. Sh!t.



The repair kit in Tbolts reply looks like it is the same case, I thought it wasn't until I figured out his picture is the inside of the case. If the transmission gears are not buggered up, I may only need the case half itself. Anyone know if the case half is available by itself?



Thanks for the replies.



Chuck

The kit Tbolt put up is differeent, it has a little more aluminum , and uses a neeedle bearing on the output shaft, I uses a different transmission stack, shims,and dler gear.

 

Re: Pictures

So there are improvements in the tranny over what is in mine? I think my case is the upgraded one due to the 15mm kick shaft, not sure about much else though.



Is the bearing different that the one in my pictures? I can't really tell, but the one in the picture of the kit and the one in my picture looks similar.

The kit Tbolt put up is differeent, it has a little more aluminum , and uses a neeedle bearing on the output shaft, I uses a different transmission stack, shims,and dler gear.

 

Re: Pictures

So there are improvements in the tranny over what is in mine? I think my case is the upgraded one due to the 15mm kick shaft, not sure about much else though.



Is the bearing different that the one in my pictures? I can't really tell, but the one in the picture of the kit and the one in my picture looks similar.

there were two different upgrades, one that upgraded the bearing to a higher quality bearing with a sleeve , and one that uses a needle bearing , those use a smooth output shaft because the shaft is now the inner race.

 

Cetris we cant really see you need to take off the Idler gear thats touching the basket and the kickstart.. We need to see the bearing behind that.. where the trans shaft is and then we can tell you if it has the different bearing cause thats the bearing that changes.. You need to pull that gear off and take a pic than we can you... OOppss sorry the basket is gone lol. But pull the idler gear thats still touching the kicker.. If the bearing where the trans shaft is that the idler is attached to if that beaing is a needle bearing then its the updated one.. IF its a roller bearing like there on the crank its the older one.. So remove the gear off of that transmission shaft take a pic and I can tell ya...

 

Cetris we cant really see you need to take off the Idler gear thats touching the basket and the kickstart.. We need to see the bearing behind that.. where the trans shaft is and then we can tell you if it has the different bearing cause thats the bearing that changes.. You need to pull that gear off and take a pic than we can you... OOppss sorry the basket is gone lol. But pull the idler gear thats still touching the kicker.. If the bearing where the trans shaft is that the idler is attached to if that beaing is a needle bearing then its the updated one.. IF its a roller bearing like there on the crank its the older one.. So remove the gear off of that transmission shaft take a pic and I can tell ya...

see the splines on the output shaft, it is an earlier case, might have a sleeved bearing, but is not a neelde bearing case.

 

Thanks guys, pictures coming......

 

Cetris no need to Matt called it.. Its NOT a new case he can see the splines on the trans shaft.... If it had the updated cases the shaft is smoth you have to use a different trans shaft with the new cases... Repair Kit for YX 160/150 case - Pit Bike Engine Parts - Parts & Kits ZS 155cc & YX160 - Repair Kit for YX 160/150 case - TBolt USA, LLC Here is the new case with the new shaft... And if you have a 15mm kicker I would say thats REAL strange.. I thought if it had the 15mm kicker it had the updated cases.. Maybe it was split and that larger shaft was installed and put back together ??? I dont know....

 

The bearing on the shaft just above the kicker shaft is broken.



What all has to come off the split the cases? Head, cylinder, and how much of this crap on the right side of the motor?

 

I think I need tbolt's kit.

 

For what it's worth I would sell it to someone who want it for parts and buy a crate motor new. Thats just my opinion and how I do things but seems like it works out better in the long run.

 

Yea get the kit replace it and you will never have to mess with it agin.. The kit fixes it for good.... Get a new center case gasket too cause you will need one..

 

Kudo's to Vince at Tbolt. I got the repair kit yesterday and have started reassembling. They are definitely good people to work with.



Hopefully the reassembly will go well.