Clone? Torque Converter on new MB200-2

[dars55]

I took delivery of a Trailmaster MB200-2 mini bike a few weeks back and have been having a blast on it - except that the torque converter is acting odd. I'm assuming that this TC is a cheap Comet clone and the only number that is visible is on the outer face of the driven - G07-1.

Since the first ride, the driver doesn't engage the belt until the RPMs are much higher than they should be. I took the cover off and have watched the driver wait, wait, wait to move inward as the RPMs keep climbing. If I climb the RPMs off of idle, the bike doesn't move until I get the engine spinning higher, then it engages kind of suddenly.

I notice that the inner face of the driver is not lined up to the inner face of the driven (I've added photos showing what this looks like). This concerns me. There is some rubber dust accumulating on the driven pulley lip, so the belt is being abused somewhat.

Can anyone give advice on the pulley alignment?

Can anyone give advice on the engagement being at such a high RPM?

Thanks!

Top view showing pulley alignment:

https://goo.gl/photos/2k5Q2w27LfwH1yBE7

Overall view:

https://goo.gl/photos/MFqcZyegd42FZovq6

Driven spring:

https://goo.gl/photos/Lve8Kkovjvp12nBw7

 

[Hellion]

Hi David.

Got pics of the whole bike?

Isn't engaging suddenly what everyone wants?

 

[Bbqjoe]

For starters the back (Flat plates) are what needs to be aligned.
Use spacers, washers, whatever you can find to shim them so they align.

 

[dars55]

Hi David.

Got pics of the whole bike?

I sure do!

This was day 1, minute 1:

https://goo.gl/photos/kYbVx2kzt4tkTxtD6

This was day 1, hour 1:

https://goo.gl/photos/hv88LK2LSi2YTguD7

I've put about 30 minutes of riding on it and 2 hours of inspection and I have to say that I am impressed with the build quality. I've been all over this bike and I didn't find any 'they bolted this on upside down' kind of things that I've seen on China assembled vehicles I owned in the early 2000's. The family had 3 Apollo 125 pit bike's that were famous for issues obviously a result of poor QC. I remember one of them I uncrated and found that the decals had been attached upside down. If you don't read English, seeing SSOɹƆO┴OW wouldn't raise any red flags!

I have owned mini bikes and go karts in the 70's, motocross and enduro bikes in the 80's, skipped most of the 90's, then as an 'adult' between 2000 - present have owned motocross bikes and 4 wheelers, go karts, and other assorted childrens machines (that I informed the kids they really wanted). In the last 17 years, I've had a Jeng Ching (sp) Panda Honda 50 clone (registered for the street), 3 Apollo 125 MX style pit bikes, Yerf Dog suspended go kart, vintage street kart, Husqvarna Husky Boy 50, Lem 50, KX65, RM250, KX250, Raptor 660, Polaris Trailblazer 250, Katana 600... and then it was all gone after the divorce. All of it.

Now I am restarting my life long passion for having things, with engines, in my garage. I'm out of touch with the current powersports offerings and did some research and decided on the MB200-2. I wanted suspension in the rear so I paid the $799 for this bike instead of going with the less expensive Baha style without rear shocks. As I said, the build quality has impressed me especially after the quality problems I experienced with the bikes back in the early 2000's. The bike arrived via UPS Freight in it's shipping crate and required partial assembly. I had to:

• Attach the handlebar assembly
• Attach the top of the rear shocks
• Attach the front fender
• Attach the front tire
• Add gas
• Change the oil (it had oil in it that I wasn't expecting)

Everything went together easily. I checked all fasteners, bolts, and nuts to make sure everything was correct and I didn't find any that needed attention. I did think that the chain was too tight, so I loosened the rear axle and used the chain tensioners to add (a little) slack to the chain. Adding gas on these is tricky because the actual gas tank is on top of the engine and that places the filler cap right under the fake tank. My gas can has about a 12" spout so I was able to position the can to the side of the bike and the spout reached to the fill hole. No spillage, but it does require special attention and I feel should not be done by young riders with a hot engine. After this was all done I slid the fuel valve to the open position, slid the choke to the on (or start) position, clicked the on/off handlebar switch to the on position and the engine started on the 2nd pull. It sounded good and has run very well. The muffler gives it a quiet sound while under load, but when the throttle is closed at the end of a higher RPM run, the engine will pop pop pop as it compression brakes in deceleration.

Other than the odd behavior of the TQ (the original reason for this lengthy post) I have zero complaints with the mini bike and the dealer I purchased from also has my high recommendation. I don't know the policy here about mentioning dealers and I have withheld the name so as not to come across as a shill.

 

[Bbqjoe]

I don't know the policy here about mentioning dealers and I have withheld the name so as not to come across as a shill.

We don't much care about shills here, but we will gladly take any shillings.

 

[KartFab]

if its catching, then you should open the drive unit and check the hub springs, and weights.

https://www.youtube.com/watch?v=C9yPHtfJO9w

 

[itsid]

well I doubt it's a maintenace issue really, that thing's new...
I can't see what could possibly be wrong with it (cheap clone or not)

The ONE thing I see is wrong however is the gap in the driver.
it's too big (the belt should be "almost touching" the sheaves in idle)
that 1/4" gap is far too big and likely the cause of your troubles.

chances are that's NOT the correct belt!
the 669 belt I am aware of is for a 50cc gy6 scooter CVT NOT a series 30 TC!

'sid

 

[dars55]

if its catching, then you should open the drive unit and check the hub springs, and weights.

I removed the driver and added a shim (washer) to bring the stationary side out to become even with the stationary side of the driven. The inside of the driven had some black material smudged into the inside of the outer half and the same black material was on the contact areas of the mechanism that has the springs around it.

I cleaned this all off and cleaned the entire driver unit, then reassembled. I do notice that the belt does not have the recommended slack (see photo link) that I see in the Comet 30 manual. I know this isn't a Comet but I would think that the same recommendation would be true for this unit.

I'm going to watch the video that covers cleaning and follow what I see.

Thanks Kartfab (I've seen your videos btw)!

---------- Post added at 11:27 AM ---------- Previous post was at 11:12 AM ----------

We don't much care about shills here, but we will gladly take any shillings.

Ok then here it goes: I purchased from gokartmasters.com.

Once I had decided on the model of fun that I was going to buy, I looked at different dealers and just decided on them. I placed my order (a few weeks ago) on Saturday afternoon, and the crate was in my driveway when I came home from work on Friday. I received shipping confirmation and a tracking number for UPS freight on Monday from them and, overall, I had a great experience.

Then a strange thing happened: Last week I received an email from them stating that my warranty order (no charge) for a Mini bike belt had shipped. Strange - I didn't order a belt. I emailed them and their reply said "We received a review today on our site for the mini bike and was assuming that the review was submitted by you. We wanted to go ahead and send you a belt in case you need it for the repair. If the review wasn't yours, you can still keep the belt for future use. Let us know if you have any questions." I hadn't left a review and thought this was strange, but great customer service. I went to their site and sure enough, there was a short 2 line review left by someone named David (my name) that said their belt was smoking but they hadn't had time to look into it yet. The no charge belt was delivered a couple of days ago.

So, if you buy from them and want a free belt, just leave a review saying your belt is smoking. Hmm... I wonder if I leave a review and say that the engine is smoking if they'll send me a new one...???

---------- Post added at 11:30 AM ---------- Previous post was at 11:27 AM ----------

The ONE thing I see is wrong however is the gap in the driver.
it's too big (the belt should be "almost touching" the sheaves in idle)
that 1/4" gap is far too big and likely the cause of your troubles.

chances are that's NOT the correct belt!
the 669 belt I am aware of is for a 50cc gy6 scooter CVT NOT a series 30 TC!

'sid

Sid-

If you read my story in another post I just made - I have another belt that isn't the same as the one installed. Can you look at the photo linked below to see the other belt. Does it look like it might make a difference?

https://goo.gl/photos/NjWsLe4pTDtpgAas5

 

[Hellion]

You don't need off-site photo hosting for DIY, you can upload them here and they render larger than most other places, I'm not sure they're compressed or resized...

Good review on the bike. Looks like another future purchase for me. I like the Baja Warrior I have now...

Any way to turn the shipping "crate" into the base of a nice work table or something useful?

Maybe re-purpose the pallet wood too, to the same end...

This was day 1, minute 1:

This was day 1, hour 1:

The belt(s):

 

[itsid]

swap the belt and see if that makes a difference (I'd bet it will) ..
that 669 is just as I thought it is a gy6 belt (wrong angles, wrong width, wrong being symmetric....)

'sid

 

[dars55]

swap the belt and see if that makes a difference (I'd bet it will) ..'sid

I'm headed to the garage this morning and I'll change out that belt. I will let you know if there is any improvement/change - and thank you for sticking with me on this.

 

[dars55]

I did the belt swap jut a few minutes ago and I'm not seeing any difference. The 2 belts were the same length, width, and both have the same asymmetrical sides (flat on one side, angled on the other). The driven is clean, and the inner piece (I don't know the correct name) will drop through the clutch (that has the springs around it), so according to the video that Kartfab linked me to, it isn't getting hung there. I do notice that when I raise the RPM's steadily, a little at a time, the outer hub (that moves in and contacts the belt) will sometimes move out away from the belt. Then as the RPMs climb more, will suddenly move inwards. That just seems odd - like it's being pulled outwards then jumps back to moving inwards.

Overall, the driven makes odd noises during riding. It will make a ringing chatter during certain conditions, almost sounding like a centrifugal clutch. It will make strange sounds sometimes during deceleration. I've had other torque converters (all Comet) on other vehicles and I don't remember them sounding like this. Mind you, it's been about 13 years since I had a TC machine (or any machine) so maybe I'm just not remembering the sounds and performance right. I just don't remember a TC machine not starting to move when the RPMs are raised above idle.

Am I wrong? Do TC's not start to engage just above idle?

 

[Bbqjoe]

It's quite possible the chain is hitting the back side of the driven.
Take a look for marking on it.

If there is chain marks, chances are that your driven isn't parallel to your rear sprocket.