Fairbanks morse driven. Help!

Mini Bike & Go-Kart Parts

#1
IMG_20201229_110903602.jpg IMG_20201229_110858040.jpg IMG_20201229_110848498.jpg I have an MTD Columbia I am putting back together. I can't find a driver so I am going to change everything to a 20 series comet. I need help on disassembing the driven part. The sprocket is missing teeth and I need to be able to hook up the comet. I took off the bolt on the side opposite the driven. That is all I have done so far. Thanks in advance
 

mustangfrank

Well-Known Member
#2
View attachment 273017 View attachment 273018 View attachment 273019 I have an MTD Columbia I am putting back together. I can't find a driver so I am going to change everything to a 20 series comet. I need help on disassembing the driven part. The sprocket is missing teeth and I need to be able to hook up the comet. I took off the bolt on the side opposite the driven. That is all I have done so far. Thanks in advance
I see one of your ramp/arms on the spider is broken off already, good thing you are replacing both clutches. Not being a smartass but it's easier to get the clutch nut off on the bike with the wheel and chain holding it from rotating.
I'm one for three on those as far as saving the original jackshaft, the clutch comes off a little easier than the sprocket but they're usually rust welded on pretty good. If you can drill and tap a new jackshaft just cut it and celebrate with a beer. The bearing bracket is the HTF part, I don't risk messing those up.
 
#3
They were not broken, don't ask. I don't have A chain the one bolt came off easy. I thought it would just slide out the other side. Do you know what sprocket i need? It's a 10 tooth but that's all I know. Thank you
 

mustangfrank

Well-Known Member
#4
They were not broken, don't ask. I don't have A chain the one bolt came off easy. I thought it would just slide out the other side. Do you know what sprocket i need? It's a 10 tooth but that's all I know. Thank you
Two of mine were stock 10 tooth jackshaft, 40 tooth sprocket and I think some literature mentioned a 4:1 ratio being stock. I never knew why when I had one as a kid but the top end was always higher than my buddies...:scooter:
 

mustangfrank

Well-Known Member
#5
They were not broken, don't ask. I don't have A chain the one bolt came off easy. I thought it would just slide out the other side. Do you know what sprocket i need? It's a 10 tooth but that's all I know. Thank you
If I read that wrong the first time, the jackshaft sprocket is a "B" type for #40 chain, 5/8" shaft...most of your usual minibike parts house have them, I tend to order from GoKart Supply because they list the most tooth options.
 
#6
If I read that wrong the first time, the jackshaft sprocket is a "B" type for #40 chain, 5/8" shaft...most of your usual minibike parts house have them, I tend to order from GoKart Supply because they list the most tooth options.
Thank you, I got it all apart. When I put a 20 series on my bike, I assume everything as far as driver and driven are not going to line up correct? I will check go cart supply
 

mustangfrank

Well-Known Member
#8
Thank you, I got it all apart. When I put a 20 series on my bike, I assume everything as far as driver and driven are not going to line up correct? I will check go cart supply
You'll have minor shimming but the 20 series driven runs "flipped" just like your original.
 

mustangfrank

Well-Known Member
#12
What is better to run for my application, 20 or 30 series. Will my cover still fit?
I think for whatever little (10%) overdrive gain with the 30 series it wasn't worth dealing with the alignment issues to keep the factory cover when I stared at mine. A 20 series is a drop in replacement with just fractional shimming, because it installs "flipped", sheave out, cam/spider in.
 

cfh

Well-Known Member
#13
Frankly the only advantage i see to a series30 is the price (they are cheaper.) I actually like how the series20 work/run better than a series30. But man series30 is cheap.... for $55 bucks (shipped!) you get everything you need. On series20, it's almost double that (drive/driven/belt), and you don't get that nifty black plastic cover...
 

cfh

Well-Known Member
#15
Short answer on the comet versus clone... save yourself money use the clone. I can’t tell any difference between genuine comet and the eBay clones. I’m running original Tecumseh motors and nothing crazy high performance. I can’t even tell the difference between original and Chinese belts. Also you can mix them. sometimes i have a Comet drive and a clone driven. I always use a clone driven as they are half the price of a comet. On the drive, i can go either way. But i just can't see the difference.
 
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#16
Short answer on the comet versus clone... save yourself money use the clone. I can’t tell any difference between genuine comet and the eBay clones.
for me it seems like the red spring thats in the clone driven holds up better then the green spring/comet does....:scooter:
 

mustangfrank

Well-Known Member
#17
Thanks for the input. So is it worth spending the money for a comet over the less expensive ones you see on ebay?
I always buy genuine Comet for my keepers for the obvious Buy American reason plus I don't like to wonder about what I'm giving up with the copy. Gonna try linking a video, a dealer that sells both breaks down the differences. Most interesting part for me was the quality grades within Chinese manufacturing he discusses.

Part 1:


Part 2:


Link to the page if I messed it up...

http://www.studzracing.com/product-p/218-asterisk--asterisk--asterisk-.htm
 

cfh

Well-Known Member
#18
i don't trust anyone that films a youtube video VERTICAL. for damn sake, turn the phone! and it is CRACK or something. if you spend the time to do an informational video and you record it vertical, immediately i put you in the "doofus" category. you've lost your position, you're clearly not an expert in the field if you don't give a crap to film your video correctly.
 
#19
I always buy genuine Comet for my keepers for the obvious Buy American reason plus I don't like to wonder about what I'm giving up with the copy. Gonna try linking a video, a dealer that sells both breaks down the differences. Most interesting part for me was the quality grades within Chinese manufacturing he discusses.

Part 1:


Part 2:


Link to the page if I messed it up...

http://www.studzracing.com/product-p/218-asterisk--asterisk--asterisk-.htm
Thank you, I actually watched that video. I just asked because the comet is about double the price of the clones. I appreciate everyone's input as always. I learn something everyday I read something on the forum. Happy New year and thanks again. Oh yeah I have a brand new 30 series driver. 3/4" with the hardware if anyone is interested. It came with a box of parts. Let me know.
 

mustangfrank

Well-Known Member
#20
Thank you, I actually watched that video. I just asked because the comet is about double the price of the clones. I appreciate everyone's input as always. I learn something everyday I read something on the forum. Happy New year and thanks again. Oh yeah I have a brand new 30 series driver. 3/4" with the hardware if anyone is interested. It came with a box of parts. Let me know.
I'm not rich, I struggle with similar decisions all the time buying parts for my old Fords and tools.

Post that clutch up, the classifieds work pretty good on here.

Thank you, Happy New Year to you too!
 

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