Coleman BT200x, stock, fresh out the box, will not accelerate..

[smalls415]

Hey All, first post here, hoping to get some answers or feed back!

I picked up a Coleman bt200x from Overtons during this quarantine. the minibike came very assembled accept the front. Anyway, got her up and running, oil gas all that good stuff.

But for the love of god she will not accelerate.

I adjusted the chain tension and made sure the rear axle was straight (that part was pre-assembled, and was not put on straight at all). I did one lap around the yard or so. Let her run some more, then killed the engine. But, the chain keeps goin in and out from too tight, to too loose. The rear wheel is on straight... And now when I twist the throttle she won't move at all! I am quite beginner here and trying to just understand best I can, plus since shelter in place my friends cant come over and lend a hand, but I adjust the chain and it'll either be too tight or too loose, during the rotation of the wheel.

If this doest make sense please reach out and I'll try to clarify, though this isn't making sense to me right now.

Cheers ,
-Smalls

 

[smalls415]

UPDATE: my friend who works at a scooter shop said its probably something with my rear axle, though I think its the chain adjusters. One of them came with the bike so stripped the nut wouldn't hold onto it. I've ordered 2 from Coleman, the first one that arrived snapped right in half as soon as I tried to tighten the nut. The second is on its way, hope that makes a difference....

 

[RobertC]

Hey Smalls...welcome to the OldMiniBikes...!

I know that is frustrating. Similar throttle issue with my very first mini bike, in 1970.

We didn't know how to fix it, and had to take it back to the vendor for repair.

And we're so anxious to ride on that first day.

Anyway, enough regression on my part lol.

Now, about your bike, if you can, post some pictures of the throttle and carburetor, as well as the drivetrain...clutch, chain, back wheel sprocket, etc. So we can get some helpful ideas going on for you.

For pics, turn your phone sideways, or the pics post sideways...idk why, I just know if you turn your phone sideways yours posted pics end up oriented correctly. To post the pics, use the attach files option, select your photo from your phone's files, and select full image, instead of thumbnail.

 

[smalls415]

Hey!

So I ended up getting her running and boppn around. But now she won't accelerate again! I put on the stage 1 upgrade from gopowersports. Air filter, new jet, new exhaust. And now she won't go AGAIN! I've checked everything up and down a million times it seems. It starts fine, idles fine. doesn't die when I rev it.

I checked the tension of the chain, seems fine as well, if not perfect. Any clues? I'll attach some pics soon
-Smalls

UPDATE: attached pics and included the rear adjusters, they are really in a good spot. Im gettn very very slow acceleration now. Been messing with it all morning. Let me know if anyones got some ideas! Thanks yall!

 

[smalls415]

UPDATE: attached pics and included the rear adjusters, they are really in a good spot. Im gettn very very slow acceleration now. Been messing with it all morning. Let me know if anyones got some ideas! Thanks yall![/QUOTE]


MORE PICS

 

[SAS289]

First thing I would do is take the chain off the jackshaft and rev it without a load. This just separates the engine from the rest of the drive train. If it revs ok then the problem may be from the clutch to the back wheel. If it doesn't rev ok then it is engine related. The throttle was already mentioned here as one possibility.
If it revs ok with the chain off of the jackshaft raise the bike up and see how easy or not the back wheel spins and go from there. If the back wheel spins ok you could still have an engine related problem. This time you will know it only happens under a load.

Can you tell if there is full clutch engagement when you first take off? Even with that gearing it's fairly easy to feel full engagement.

 

[smalls415]

"]First thing I would do is take the chain off the jackshaft and rev it without a load. ...."

Yea my thoughts exactly, I lifted the whole bike off the ground with some cinder blocks, back wheel not touching the ground. Started her up, it revs perfectly fine, back wheel goes, but that was with the chain on.

Just to be clear, you're saying take the chain off and try this again? Sorry I'm very new to this, tryna learn as I go along. Thank you for this, it was super helpful!

-Smalls

 

[SAS289]

UPDATE: attached pics and included the rear adjusters, they are really in a good spot. Im gettn very very slow acceleration now. Been messing with it all morning. Let me know if anyones got some ideas! Thanks yall!

MORE PICS[/QUOTE]

If you think it revs fine with the chains on then do not take them off. It's still pretty much a no load test.

I'm wondering if your throttle cable needs adjusting? You should see the throttle linkage move as soon as you start twisting. At full throttle it should come in contact with that gov fine tuning screw that they may have welded into place. If you don't have full throttle linkage travel it may rev no load but not under load.

The first thing that caught my eye in your pictures was the return spring. Your spring looks so short you wonder how the thing returns to idle? Maybe they started using a shorter return spring because the return spring on my throttle looks longer and I cut coils off to shorten it when I got the bike. My Coleman is from late 2016. I cut coils to take the bind out.

 

[smalls415]

@SAS289 I am lookin at the spring compared to peoples online, and it does look like it is a lot shorter then the other ones I am seeing. Maybe I should hit up Coleman and see if they'll send me a new spring since it came this short already?

I ended up taking the chain and clutch apart to check the pads (out of another friends recommendation) but everything is fine in there.

 

[SAS289]

Or you could just leave the spring there and add another. 2 return springs are better than one as long as they don't make the throttle too tight. I added a second spring on my throttle. It matches the spring used on Honda GX200's and clone engines. I made my own but there is a Honda part number you can order.

Here's a video that covers the Honda part number and shows where the spring goes.

 

[manchester1]

I didn't read all the comments but those clutches aren't very good. Put a couple drops of oil on the clutch bushing.

 

[smalls415]

I didn't read all the comments but those clutches aren't very good. Put a couple drops of oil on the clutch bushing.

thank you!

 

[smalls415]

Or you could just leave the spring there and add another. 2 return springs are better than one as long as they don't make the throttle too tight. I added a second spring on my throttle. It matches the spring used on Honda GX200's and clone engines. I made my own but there is a Honda part number you can order.

Here's a video that covers the Honda part number and shows where the spring goes.

rad, gonna watch thank you for the link!

 

[SAS289]

I didn't read all the comments but those clutches aren't very good. Put a couple drops of oil on the clutch bushing.

A few drops of oil would be a good way to see if the clutch may be the issue. But afterwards it would be a good idea to open it up to clean and grease the caged roller bearing his clutch has. They don't come with much lube at all. I don't ride a lot but still open mine up every couple rides or so. Easy enough to do with snap ring pliers, brake clean, and wheel bearing grease. If you use too much grease it will make it's way out onto the drum area.