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Shifter Drum Retaining hardware
Posted: Sat Feb 15, 2014 12:18 pm
by water cooled
While working on the shifter drum, I noticed that one of the 4 retaining screws was a different length when it came out. I checked the parts manual and it shows item 13 and item 15 leading me to believe they are different parts. However, the p/n's are identical.
Are the 4 retaining bolts (item 13 and 15) suppose to be identical?
http://www.oldjapanesebikes.com/mraxl_G ... shift.html
Re: Shifter Drum Retaining hardware
Posted: Sat Feb 15, 2014 3:21 pm
by tz375
As far as I remember, they are the same. As long as they are not protruding through to snag a gear they should be fine.
Re: Shifter Drum Retaining hardware
Posted: Sat Feb 15, 2014 4:53 pm
by water cooled
I figured it was just a wrong screw that got installed. Thanks R.
Re: Shifter Drum - Variance to Parts Drawing
Posted: Tue Feb 18, 2014 9:21 am
by water cooled
After performing a dry run install of the shifter drum assy, I noticed a variance in the actual shift fork vs. the exploded drawing and need to know if there was a difference or change between model years (1974 vs 1977) specifically regarding the shift fork part numbers.
My current setup uses a 1974 shift drum assy with 74 shift forks. The transmission set is 1977. Obviously this setup works as I have been using it for several years. But clearly there is a difference in the actual part vs what is illustrated.
If you look at the exploded view, the two rear shift forks (item 1) have the pin location clearly bias to the (installed) left of the fork. It also shows the double web reinforcement of the fork on the left side as well and the single web on the right.
Can anyone confirm if the shift fork parts (item 1) are different between 74 and 77. If not, is the exploded view simplyincorrectly showing the actual shape of the shift fork.
You can see that the actual pin location as well as the double reinforcement webs of my shift fork is bias to the (installed) right side
The half moons at the top of the shift fork are correct but the pin and reinforcement webs appear to be a mirror image of what is illustrated in the exploded view.

Re: Shifter Drum Retaining hardware
Posted: Tue Feb 18, 2014 12:53 pm
by tz375
I just pull them out of the motor and throw them in a box and then choose the best set to fit in the motor I'm building. OK so that's close enough to the facts... I suspect that the parts were drawn up before the 72 went into production and have only been updated for major changes since 71/2.
Re: Shifter Drum Retaining hardware
Posted: Tue Feb 18, 2014 1:20 pm
by water cooled
I wondered if it was just pre-production drawing but i didnt want to find out there was an MAB change to the shift forks. I worry enough about matching parts from different years.
Thanks for the input on both posts. Appreciated it!