I have not read any posts lately of issues with the chain coming off or installing the extra engine braces, so I assume the recent models have resolved the mushy rubber engine mount that let the engine move so much when accelerating that it created too much slack in the chain, and it sometimes comes off. Sometimes on the 90, I can actually hear the chain slipping teeth. The chain is tight enough when stopped, but as the engine moves downward while torqueing, the 2 sprockets move closer to each other and the slack problem occurs.

I have 2 of the earlier models and have struggled with this issue. I've installed braces from Redcat, but they broke after a few weeks. Does anyone know if an upgraded engine mount is available for purchase seperately? I'm probably going to build a stronger engine brace to stop the movement, but it will transfer more vibration to the frame so a new engine mount would be a better solution.

 

After I made this post, I stopped by and looked at some new models at a dealer. I don't think there is an improved engine mount. It looks like they totally changed the way the engine is mounted. It used to be only supported by a big rubber mount at the rear, now there's a mount at the top and a large bracket at the bottom. Guess I'm on my own to come up with a better mount.

 

so far we haven't had a chain problem with eaither the 70 or the 90 but i did notice when they're sitting on the blocks and i rev up the motor a little the engines move alot, i bet they move between 1/2 to maybe just under 3/4 of an inch, i 'm with you and will probably install a front motor mount brace. the top motor mount is just like you said made of rubber, these are new 06 models.

 

I lucked out I guess. I ordered two 90's and when they showed up they said Sla 107. I went ahead and called Sunl and they told me I got the newest design with the engine mount upgradeand slighty bigger engine. I noticed that it's directly mounted to the rear and the top of the engine to reduce the engine torque. I have noticed though there is some engine vibration at higher speeds because of no rubber mounts but that's better than the chain coming off. The only gripe I had was on one of the bikes the chain was loose and the adjustment was maxed out so I drilled the slots out a little longer and it works great. I also installed upgraded chain adjustment hardware. Anyone no where I can find the proper size gease zerk attachment? It seems they are smaller than whats used on our cars.

 

Yep, I noticed at a streetside dealer the other day that there is now a 95cc model and a 110. I can't imagine a 110 on that little frame. I also noticed the engine is laid out completely different, starter on top, etc.

 

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Sounds like stronger engine mounts needs to be designed / created. I'm sure a few local welding shops in your area could give you a few good ideas.

Also, you might want to install a Spring Loaded chain tensioner. We installed one on our '03 Pred-90. One of the best upgrades we've done to it. Not too sure if you can find a "bolt on" Spring Loaded chain tensioner. Perhaps your local welder guy could make one fit? Worth asking around....

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I just found out on my son's 90 today that the chain had rubbed the chain guard on the front sprocket. Somehow the clip link came off and he dropped the entrie chain. As i was fixing it i noticed that the lower bolt on the chain guard had 3 washer, the top had none. When I looked at the guard you could see that the chain had rubbed out a notch in the top of the guard. No wonder it popped. Something to check if you haven't already. I reduced the lower bolt to two washer and put two on the top, seems to have done the trick.

 

I removed the plastic cheapo so called chain guard all together. One thing it fit like crap and would of fell off in a few hours. Make sure you check the rear main wheel nuts mine were soo loose I had 1/4 inch of side to side play. Just check every nut and bolt on these things just to be sure.

 

Nuts are a killer on this thing. I went out and bought a bunch of metric lock nuts and changes most everyone on it and put thread locker on it. Both of the cap nuts came off the exhaust. Anyone had the plastic crack yet on it? I was trying to think of a solution to patch/stop the crack and didn't want to deal with glassing it.

 

I had plastic crack on mine. I used some flexible sealant from Home Depot that was made for Recreational Vehicles. Its been holding up for 4 months now. Black color. The tube is around 4 inches long.