OK, So I figured out the MB165 Jack Shaft...

#1
So, there are 2 versions of the jack shaft(JS). They have 2 different tensioners. The old style used a spring that connected to the upper right JS cover holder. The roller on this one was small and this was not a good system. That is the one I had. The new ones (that have been around awhile) have a spring that wraps around the tensioner post and connects to a "tab" for spring pressure. Anyhow, I was about to pull the plug on another Promod JS, but I called Monster Scooter for an availability check and they gave me a 5% internet code of AR0095 so I could not resist. I know I am going to kick myself long term for not getting the Promod JS, but I am pretty sure we will move on from mini bikes to street legal Honda Mini Trail clones over the next few years.
 

C9H13NO3

Active Member
#2
So, there are 2 versions of the jack shaft(JS). They have 2 different tensioners. The old style used a spring that connected to the upper right JS cover holder. The roller on this one was small and this was not a good system. That is the one I had. The new ones (that have been around awhile) have a spring that wraps around the tensioner post and connects to a "tab" for spring pressure. Anyhow, I was about to pull the plug on another Promod JS, but I called Monster Scooter for an availability check and they gave me a 5% internet code of AR0095 so I could not resist. I know I am going to kick myself long term for not getting the Promod JS, but I am pretty sure we will move on from mini bikes to street legal Honda Mini Trail clones over the next few years.
Took ya long enough!! :laugh::laugh:

I'm just bustin' on you.
 
#3
If your wanting to fix the bike on the cheap, and maybe ride it just a little. Then buy replacement parts for the China built MB165 JS.
But what it all comes down to is..
Fix it with the same thing that broke?
Or Fix it better!!!!!!!!
What we have learned=
35 Max-t clutch and chain for the short primary will smooth out the chain noise and vibration. (just roll your stock MB165 across the shop and hear the farm implement sounds coming from your chains) Want to play with different gearing.... well your kinda limited with the stock JS.
Anyway
Had to get my 2-cents in cause my name came up. :2guns:
 
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#4
Had to get my 2-cents in cause my name came up. :2guns:
never admit you search for your name on a message board (not saying you did here). :laugh:

but that comment made me think of this...

one guy on another board i go on said he did that so a bunch of us started putting his name in every post we made. he went on vacation (told us before he left) and was pissed when he got back and did his usual search thing. :lol: :lol: :lol:
 

C9H13NO3

Active Member
#5
never admit you search for your name on a message board (not saying you did here). :laugh:

but that comment made me think of this...

one guy on another board i go on said he did that so a bunch of us started putting his name in every post we made. he went on vacation (told us before he left) and was pissed when he got back and did his usual search thing. :lol: :lol: :lol:
I may have to start doing that :laugh:
 
#7
I personally read and reply to the daily post's on this forum for either= learning/sharing past experiences, offering info about our products, Or the most rewarding of all .. meeting new friends that share the same passion for this hobby.
Other forums may be different....
I don't expect a vacation any time soon or plan on searching my name out just for something to read on here ... LOL
Thanks for the advice Srigio
 
#8
Yo Promod. I appreciate you keeping up with the jack shaft issues here. Having bought 2 of your jack shafts, I know the quality product you have! I got stuck in a situation with the mb 165 project where my wife is looking over my shoulder with every purchase, and even though she saw the impressive improvement in the 2 Doodlebug Promod jack shaft replacements, it was hard to convince her to go with your better product. I got the Baja jack shaft for $68 and it really came down to the fact that I had a stock clutch cover already and that was what made the issue one of those battles that I was not ready to fight with her. She is not evil, but after giving up her full time gig as a Victoria's Secret supermodel, she has been watching the money very carefully. I am 51 and she is 23 so there is a bit of a generational gap. Its lucky she is my cousin....................
 
#9
Sorry seacamper for any sarcasm used with describing the factory style JS parts or your repair. I guess it all comes back from being a Baja warranty center for a few years and seeing all the problems I did. I really appreciate your business. In my mind the MB165 really only has one flaw (the JS system) The fake tanks kinda corny too.. But I have a blast on mine and there pretty fun to mod out and easy to keep going even on a budget.
Anyway....glad you got your bike ridable and...happy I didn't get you in trouble with the......um .....wife.
 
#11
OK, so the new JS arrives, and its on, but if anyone else runs into a HF 6.5 reengine of an MB165, I would really recommend the Promod vs the stock. I had to modify the heatshield and the stock JS frame mount, which I would not have to do with the Promod. Anyhow, its done and now I am off to get the wheels lined up.
 
#12
It ran pretty well this weekend. My sons and their friends rode the 4 bikes nonstop for 2 days with only minor problems. The MB165 was the favorite. I need to look for more of those!
Tom
 
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