Skyteam 200 (Loncin) Cam Chain Tensioner ?

[alchemysa]

Hello from Australia. This is my first post. I hope I can contribute some useful info to this forum, but first I need a little help.

I have recently picked up a Skyteam GT200. (Hunting around the net it appears this is also known as an ST200 or maybe a United Motors DTF200.). I have also located various parts diagrams and an operators manual. My bike has an overhead cam engine that I believe is made by Loncin. Virtually identical bikes appear to have a pushrod engine by some other maker.

My question concerns the cam chain tensioner. Whats the procedure to adjust it? I've looked all over the net but I can't find any specific details on this type of tensioner. Its in an extremely awkward spot behind the starter motor, however I've managed to removed the small cap screw from the tensioner. I can see a castellated nut inside, and a slotted screw inside that. I'm guessing one of those is the tensioner and the other is a lock screw, but which is which and what do I do next? (I presume I have to turn one of these screws while the engine is running). A couple of pics are attached. Any help regarding the correct procedure would be appreciated.

Regards.

[alchemysa]

I might have found the answer. The Skyteam (Loncin) tensioner appears to be the same as in the Honda GY6 engine.





As described in video 1 the safest option seems to be to remove the tensioner completely, retract it by turning it clockwise, then turn it anticlockwise after reinstalling it.

I'm not sure if I can retract it while its still in the engine. The video isn't really clear on that.

(Video 2 is confusing. He shows it being wound up and down but then he says you don't have to do anything because its automatic.)

[david3921]

It's automatic. No need to remove and adjust.

[Weldangrind]

Excellent info!

While the second vid is entertaining, I would focus on the first video for your bike. I was wondering how the automatic tensioner works in an OHC engine, and the first video explains it nicely for me. I wouldn't worry about retracting the tensioner before removal; just back off the mounting screws equally until it can be removed. It seems to me that this is an improvement over the clumsy XR200 design.

[alchemysa]

Originally Posted by david3921

It's automatic. No need to remove and adjust.

Hopefully you are correct David. But I like to make sure things are working as they should. I think the first video is suggesting that if the tensioner has accidently been installed in the extended position it cannot retract, and hence could damage the guide or the tensioner itself. I think the engine is a bit noisy so I just want to make sure the tensioner is actually doing some tensioning. Pity its so hard to get at behind the starter.

[alchemysa]

Originally Posted by Weldangrind

Excellent info!

Hello Weldangrind. Isn't youtube great! I also found a video with a tip on how i might get the chain rattle out of my Honda.

[SpudRider]

Welcome; we are glad you joined us.

Your automatic cam chain tensioner works the same as the automatic cam chain tensioners in my Zongshen 200GY-2 and my Honda CRF250X. You don't need to manually adjust the tensioner; it will automatically extend as the cam chain stretches.

If you are concerned the tensioner was incorrectly installed in the extended position, you can retract the plunger of the tensioner, and allow it to extend again. You can perform this procedure while the tensioner is still installed in the motorcycle. Merely remove the center bolt, and insert a small, flat blade screwdriver. Turn the screwdriver clockwise, and the plunger will retract. Then release the screwdriver, and the plunger will extend again. However, the cam chain would not rattle if the plunger was installed in the extended position.

You can remove the automatic cam chain tensioner to verify it is not broken by following the procedure in the first video.



If the plunger is working properly, and the cam chain stretches beyond the capacity of the automatic cam chain tensioner to compensate, you need to install a new cam chain.

[Weldangrind]

Originally Posted by alchemysa

Hello Weldangrind. Isn't youtube great! I also found a video with a tip on how i might get the chain rattle out of my Honda.

Excellent! Thanks for sharing that vid.

[alchemysa]

Today I removed the cam chain tensioner to check it out. I hadnt done this before because I was a little puzzled about how to remove the starter motor. At first glance it looked like the whole side cover might need to come off. But of course it doesn't. Its just a matter of removing the two 8mm bolts at the rear end of the starter then tapping it backwards. The front end is just snuggly held by a rubber 'O' ring.

A few points for anyone else doing this.

1. When removing the rear bolts note that there are a couple of spacers under the starter. Don't lose them.

2. Although its probably not essential, its also a good idea to remove the round cover just below the front end of the starter. Its held on by three 8mm bolts. A few drips of oil might come out, but not much more. Removing this cover will help you line up the gears when reinstalling the starter.

3. When you pull off this cover the starter gear will come with it. (You'll be reinstalling the gear and the cover separately. Theres also a washer between the cover and the gear).

4. Reinstall the starter. A little oil on the O ring helps it to go back in.

4. After you've reinstalled the starter, push the starter gear back into its cavity between the starter motor and gearbox. (Its easier to mesh the gears this way, without the cover.)

5. Finally, reinstall the cover. The bolt holes only line up in one position so you can't go wrong.