Rear Axle Spacers & Chain Tension

[Brew2]

Gio X21.....110 Dirt Bike.

Am a complete novice re motorcycles and am trying to assemble a new Gio X21 with no instructions. Most of the assembly appears to be common sense, but am a little uncertain about the rear axle spacers.

There are three spacers of various lengths (small, medium, large). I've assembled the axle components as follows starting from the right side of bike....

Small spacer
Brake assembly
Medium spacer
Wheel assembly
Large spacer

I sort of assumed the small/medium spacers on one side and the large on the other would result in the wheel being in the middle of the frame, which it appears to be. Does that all sound right??

Also, with the chain on, the wheel axle is forced to the forward most position allowed by the frame. I have an inch+ of space behind the axle and none in front. The chain forces the axle forward and seems very tight to me. By pressing in the middle of the chain I can deflect it approximately 1/2 inch down. Does this sound too tight or ok?

Thanks in advance for any input.

Brew

[Weldangrind]

Welcome!

I would certainly try to place the wheel in the middle of the swingarm, but it's even more important to make sure that the sprockets line up.

It sounds like the chain is a little too tight. A new non o-ring RK or DID chain is cheap.

[Brew2]

Thanks....appreciate the insight. I'll double check the sprocket alignment and look into a slightly longer chain.

[katoranger]

We need some pics.

[Brew2]

OK....bike isn't at home so pictures will have to wait a few days. Hopefully this coming weekend.

Cheers,

Brew

[Brew2]

Oops...forgot to bring the camera when I tackled the assembly again.

In the end, I figured out that there was no other viable way to arrange the spacers on the rear axle. Changing them around either meant the brake mechanism wouldn't be in the appropriate place or the rear sprocket was too far one way or the other. Put everything back as I had it originally and while the sprockets don't line up perfectly, they are pretty close (about 1/8-1/4 inch horizontal difference between front and rear sprockets). Only way I can see to modify this is to obtain/make different size rear axle spacers.

Chain tension was still too tight. Could barely deflect the chain at all by pushing on it. Buying a new chain is likely in the works, however, in the interim, I removed a round rubber piece that deflected the chain downward between the front and rear sprockets (sorry, being new to all this I'm not sure of the names of everything). This had the effect of relieving some tension in the chain and it seems good now.

So what is/was the purpose of that rubber piece that the chain rode over? Originally thought it might be to create/relieve tension in the chain, but it's position is not adjustable, so that's not it. Does it just "clean" the chain as it rides over the rubber? The net effect on the chain, aside from the tension, is that it now goes straight from the front to rear sprockets instead of angling down from the front sprocket to the rubber thing, then straight back to the rear sprocket.

Man...after typing that I sure wish I had remembered the camera....picture is definitely worth a thousand words!!

Thanks for any thoughts.

Brew

[katoranger]

It is a chain guide that prevents the chain from rubbing on the swingarm.

[Brew2]

Ahhhhh....that makes sense.

I'll have to have a look at how close the chain gets to the swing arm without it. Hopefully, it will be ok until I either get a new chain or the current one loosens up a bit.

Appreciate the help.

Brew

[Weldangrind]

The net effect on the chain, aside from the tension, is that it now goes straight from the front to rear sprockets instead of angling down from the front sprocket to the rubber thing, then straight back to the rear sprocket.

This description is troubling me. :?:

It sounds like a chain tensioner that is found on early motocross bikes, like the old '78 PE175 I used to have. In that setup, the chain left the front sprocket, rode over and under two rollers on a spring mechanism, and then moved to the rear sprocket. Without pics, it sounds like your chain should be routed over the roller, not under. Is the arm that the rubber device is mounted to spring loaded?

I need closure here; please post some pics! :lol:

[Brew2]

Hey!! You da man!!!

Can't believe that never occured to me that the chain should ride "over" that rubber thing, not under. That likely explains the tight super chain.

Found a picture of the same bike on Ebay and the chain definitely goes over that rubber thing. Sorry I can't post pictures of mine as it is in a friends garage an hour away....but here is a link to the one from Ebay to satisfy your curiousity.

http://cgi.ebay.ca/GIOVANNI-110CC-4-STROKE-DIRT-BIKE-2010-X21D-/220758801885?pt=Motors_Powersports_Under_50cc&hash=item33663ffddd


Thanks!

[Brew2]

Oh...and no, the rubber "guide" is not spring loaded. It is just bolted in a fixed position. Chain tension seems to be adjusted via two bolts that push the rear axle further back (ie one bolt on each side of the axle).

Thanks again.

[Weldangrind]

Thanks, I feel much better now. :lol:

I failed to realize that you were describing a pit bike (even though it was posted in the pit bike section - duh). Now that I see it, I'm very familiar with it. The device that the chain slides over is a chain roller.

Happy trails!