Problem: Chain Tensioner Or Improper Wheel

[Kevron99]

OK..I finished the installations of all the parts and components of my first build. I check everything to make sure that all is tight and secure before my first run.

The engine starts at first try and then a couple of yards after I heard a "POP" and then the bike vibrates violently and then stopped. When I look at the rear wheel the chain tensioner had plowed the wheel spokes and the wheel was pulled, geared all the way to the right side or the crank side, touching the frame.

I took off the rear wheel and brought it to the bike shop for repair. After 2 hours of repair, I re-install and added a washer from the inside (Please see the attached picture the one lined in red is the washer I added). I made sure everything is tight and secure. Then I re-install the chain tensioner made sure also that it is tight and in place. I also made the chain slack a little bit because on the first start I thought I made it to tight.

Now getting ready to start the second time and..DARN it did the same thing!! The tensioner plowed the spokes again and the wheel is geared toward the right side. But this time it is not as bad as it was the first time. The wheels did not touch the frame but still leaning on right side. Could the WASHERS help a little bit that the wheels did not pull 100% to the frame?

What could be the cause of the wheel pulling to the right side when starting the engine and how could it be fixed?

Is it because of improper chain tension? could be to tight or to loose that made the chain tensioner plowed to the spokes?

Is there something I am doing wrong? I am getting Confused with this problem...

Any suggestions? Please HELP!!!!

Thanks for any feedback or suggestions.

 

[Bikeguy Joe]

The chain needs about 3/4" of slack.
Is the chain lining up properly? Look down the chain run from the rear of the bike.
Adding a washer there only slays the frame outward, it shouldn't change the chain alignment.

 

[Kevron99]

I checked the alignment from the top, but slightly from behind. I did not take full attention checking the chains from behind because it looks like it was lining up straight. Also what would you think that makes the chain tensioner from being misaligned when starting.

If the chain tensioner is the issue I would spend another big bucks for this:

Idler Chain Tensioner Kit - Motorbike Parts - Vintage Motorbikes

 

[2door]

Chain tension and alignment is very important. The kit installation intructions do not dwell on this but take it from experienced builders; You need to 1. Assure that the chain tensioner wheel is aligned with the chain. 2. The tensioner bracket is secured to the bike frame so that it can not loosen and rotate into the spokes.
Sight down the chain from the rear of the bike and pay close attention to the angle of the tensioner wheel as opposed to the chain. It HAS to be exactly parallel with the chain. If not you'll need to clamp the tensioner bracket in a vise and give it a twist to get the wheel where it rides true with the chain.
The next step sounds scary to a lot of people but it will not hurt your bike frame or compromise the integrity of it.
After you have good tensioner wheel alignment, drill a hole completely through the bracket and the chain stay (frame) and install a small, 10/32 is big enough, bolt and nut. This will prevent the tensioner bracket from moving and getting into your rear wheel/spokes.
Tom

 

[george_n_texas]

is that the upgrade sprocket? the one built into the spindle? Looks real solid. I thought he was talking about the tensioner pulling into the sprocket but his picture doesn't show any tensioner I am familiar with mine looks like this:

 

[2door]

Kevron99 is using the Manic Mechanic hub adapter. > SPROCKET ADAPTER
A well made option to the rubber (rag joint) style of sprocket attachment found in all 2 stroke motor kits today. His photo is pointing out where he spaced the chainstay away from the rear hub.
Tom

 

[Kevron99]

Chain tension and alignment is very important. The kit installation intructions do not dwell on this but take it from experienced builders; You need to 1. Assure that the chain tensioner wheel is aligned with the chain. 2. The tensioner bracket is secured to the bike frame so that it can not loosen and rotate into the spokes.
Sight down the chain from the rear of the bike and pay close attention to the angle of the tensioner wheel as opposed to the chain. It HAS to be exactly parallel with the chain. If not you'll need to clamp the tensioner bracket in a vise and give it a twist to get the wheel where it rides true with the chain.
The next step sounds scary to a lot of people but it will not hurt your bike frame or compromise the integrity of it.
After you have good tensioner wheel alignment, drill a hole completely through the bracket and the chain stay (frame) and install a small, 10/32 is big enough, bolt and nut. This will prevent the tensioner bracket from moving and getting into your rear wheel/spokes.
Tom

Thanks 2Door...Does a misaligned chain tensioner causes the wheel to pull towards the right side of the frame? I just need to rule out the possibilities of the issue.

First issue I have to clear out is that "why is it that the wheel pull to the right"?. Is it because of a mis aligned tensioner? or is it because I needed or I am missing a part that holds the wheel to its proper position "possibly a special lock washer" to hold it? or is it because of an improper chain tension that I installed it to tight or too loose?

Man so many questions to ask...

Thanks,
Kevron99

 

[2door]

Kev,
When you say the wheel pulls to the right...do you mean the bike wheel or the tensioner wheel?
Your rear wheel installation looks okay from your photo as long as it is centered in the frame and running true with the front wheel. I'm not sure you need that extra nut (spacer) between the hub and the frame but it shouldn't hurt anything.
If you're talking about the tensioner wheel, it is under a lot of force with the engine pulling the bike. It will naturally be pulled to the right. That is the reason we suggest securing the bracket to the frame...to keep it from moving. The clamping action is not always enough to hold the bracket from moving to the right, into your spokes
Tom

 

[Venice Motor Bikes]

You need to drill a tiny hole in the tensioner & screw it into the frame so it doesn't get pulled into the spokes!
Look at 2 doors pic a few posts up.

 

[Kevron99]

Kev,
When you say the wheel pulls to the right...do you mean the bike wheel or the tensioner wheel?
Your rear wheel installation looks okay from your photo as long as it is centered in the frame and running true with the front wheel. I'm not sure you need that extra nut (spacer) between the hub and the frame but it shouldn't hurt anything.
If you're talking about the tensioner wheel, it is under a lot of force with the engine pulling the bike. It will naturally be pulled to the right. That is the reason we suggest securing the bracket to the frame...to keep it from moving. The clamping action is not always enough to hold the bracket from moving to the right, into your spokes
Tom

It is the bike wheel pulling from the right. This I notice after the tensioner had plowed the spokes. When i looked at the aftermath,, the tensioner inside the spokes and the wheel to the right touching the bottom frame...

 

[Venice Motor Bikes]

Post a pic of what you are talking about.

 

[Kevron99]

Here it is...3 pictures attached. This is the aftermath...

 

[Venice Motor Bikes]

Is the wheel bent??? Does it still spin true?

 

[Kevron99]

After the tensioner plowed the wheels this is how it looks like ...I am not sure if it is bent, but what definitely I am sure off is that it leans towards the right..and the position of the wheel nut from the bottom bracket the left moved towards the front as if the engine pulled it. The right side the wheel nut position had gone backward.

 

[Venice Motor Bikes]

Ok.... so put it back where it's supossed to be, put the chain & tensioner back together & screw the tensioner into the frame.
If the wheel is bent, you need to fix it first.

I just noticed in your first pic that you have some broken spokes!!! get 'em fixed first!

 

[Kevron99]

Thanks very much Venice...I will do that..screw the tensioner to the frame..

chow

 

[biken stins]

Mine first bike did the same thing. Try lineing the chain with the bottom of sprocket. That is the way it is fed to sprocket. The screw is a great idea once lined up correctly.
When fixed roll it and check that the chain is not locked up on front sprocket.
When you go to start it Turn ON fuel, Prime the carb well, Choke it, pedal up to speed.Faster than what you were going before. Some instructions say try to use a hill. That is so you can get some speed up. When you dumped the clutch is when the wheel turned in. Good luck ! Your almost there !

 

[george_n_texas]

I gotta question is that the muffler I see in the pics? It looks like the chain material they use for butcher gloves or shark suites

 

[xlite]

I checked the alignment from the top, but slightly from behind. I did not take full attention checking the chains from behind because it looks like it was lining up straight. Also what would you think that makes the chain tensioner from being misaligned when starting.

If the chain tensioner is the issue I would spend another big bucks for this:

Idler Chain Tensioner Kit - Motorbike Parts - Vintage Motorbikes

You might consider eliminating the tensioner completely unless it is absolutely necessary. I can't count the number of guys that came back to me with busted wheels because they felt obligated to use it "just because it was there". Now I sneak the tensioner out of the kits before handing over and throw 'em in the big bucket full of them in my basement.

Kinda like with the kill switches too.

 

[Junster]

Your chain may be binding up on one of the sprockets pulling that side of the wheel forward. Try grinding the tips of the spocket teeth so they fit the chain better. Then make a shim to fit in the slot the rear wheel axle is in so the axle cannot move forward. Or maybe if there is room you can put a short bolt and nut in that slot in front of the axle. Just something that stops the axel from slipping forwards. When I was using a left side chain I used a aluminum shim behind the rear motor mount to tension the motor chain so I didn't have to use the tensioner at all.