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Discussion Starter · #64 ·
i have a question regarding the sprocket size i should use on this bike.


the one that came with the ratchet top is a 22 teeth sprocket.
it pulled a 51 teeth rear sprocket,

the new rear wheel has a drum with 44 teeth on it.


the belt drive is set up 40 in the front 62 on the clutch.


rear tire is sized 19"x4.00".


do you think i could upgrade to a 25 teeth sprocket on the tranny,
or would that be too much for the engine?
i do not care about racing from light to light, i prefer low rpms on the freeway
and this is a 4speed bike.


what's your opinion?
 

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44/25=1.76 nope, bad idea
Final drive
44/25=1.76 to high for stock
44/22=2 to high for stock
44/21=2.0952 high for stock
51/22=2.3181 FL stock FX before 1973
51/23=2.2174 stock FX 1973 & later
51/24=2.125 FX FL high for stock FL
51/25=2.04 very high for stock, FX trans or close ratio won't impress off the line
24 and 25 will rub in stock primaries, and wear holes.
48/22=2.1818 no primary wear, I run this on the avatar bike, but it has a 4 3/4 arm
Your primary
62/40=1.55
stock primary
37/24=1.5416
37/23=1.6086
37/22=1.6818
Light bike and rider will allow for similar performance to stock with the higher ratios.
Multiply final and primary ratio for overall.
 

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Discussion Starter · #67 · (Edited)
it's the last version of the star-hub mounted juice drum,
before they changed to mid-star... so up to '66 i guess?

this one:



i just recounted and found out that you're right, Jaws... i made a black dot
with a magic marker on one tooth to avoid confusion and it turns out there
was a grease stain on tooth 44 so i thought i'd be done counting...d'oh :eek:
stupid me

i was told the 25 teeth sprocket would work without grinding,
so i'll just try it on when it arrives. i'll be using a 2" belt drive set up
with external bearing support and a modified tin primary case.

maybe it's best to hold on to the 22 and try it on the road.
i guess changing the sprocket isn't that hard, if i should decide so.
after all i have a pretty tall rear tire, too.

thanks for the great info, Joe!
 

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Discussion Starter · #70 ·
ok, did a little math based on Joe's list...


correct me if i'm doing this wrong :)



rpm = mph x gear ratio x 336 / tire diameter



my tire diameter is 27" now.


gear ratio (primary x final drive would be 1.55 x 2.3181) = 3,5931:1


so at 65mph the engine would turn at 2906 rpm with the 22 sprocket


given i'd use the 25 sprocket it would be reduced to 2558 rpm


that's quite a difference
 

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ok, did a little math based on Joe's list...

correct me if i'm doing this wrong :)

rpm = mph x gear ratio x 336 / tire diameter

my tire diameter is 27" now.

gear ratio (primary x final drive would be 1.55 x 2.3181) = 3,5931:1

so at 65mph the engine would turn at 2906 rpm with the 22 sprocket

given i'd use the 25 sprocket it would be reduced to 2558 rpm

that's quite a difference
yes and yes and yes, quite a difference. You are correct.
 

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Run the 24... it will be tight but wont rub and possibly no sanding necessary. Ive only had to barely touch one case up with a hand file one time. All others worked perfect.

To be honest, I dont ride high speeds around here and I probably will go the 22 route so I can get off the line easier.

My pan was loooooong legged.
 

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Discussion Starter · #74 ·
i have decided to stay with the 22 for now.
the 25 is going on the wall and i'll see how the bike behaves when it
finally hits the road. if it's geared too low i'll change after the season
and decide which one to use, 23, 24 or 25.
anyway, it's always good to think about it and actually do the math,
otherwise it's just poking around in the mud and you might end up with
something that rides like shit...

next question on the table is the clutch. the one that was on the bike is pretty fucked up.
it crashed at some point and the bolts are bent and turn in the base plate.
i want to get a new one with 5 long bolts instead of 3 to help apply
pressure more evenly. i am pretty confused about the various opinions
on the original clutch basket cage type bearings vs the "big fix" type bearing with needles only. some say do it, some say don't, some say don't use it with a belt, i really don't know.
i tend to get the needle version because it covers much more bearing surface
and the old cage i have here looks awful, so i have to get something new anyway.

what's your experience with this?

this is the pile i have:







this is how it looked when i took it apart last year:









i guess the oem pressure plate can be reused for now, and maybe the
springs and friction plates, but not much else.
thanks for reading through all this and sharing info, it's highly appreciated and a great help.
 

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I have done both. I like the stock stuff if its in perfect order, but I always do the five fingers instead of three. Make sure you use a grease that wont get too thin and not too much either. File the holes in the plate and clean the dogs and fingers so the plates and clutches slide real nice. I always take the antirattle balls off the plates. I have seen them come apart and lock a clutch engaged.
 

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Discussion Starter · #76 ·
ok, so then this is what i've done now:


i bought the 5 finger hub, accompanied by the "big fix" needle bearing
and "retainer" style guard plate, together with the old style clutch relief bearing
and rod and a stock adjusting screw (no ball), together with a side of fries :rolleyes:


i am going to reuse the pressure plate, steel discs
(they're in the ultra sound now and seem to be nice and flat)
and friction discs.


let's see how it works out :)
 

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Discussion Starter · #79 · (Edited)
i assembled the new clutch parts with the needle bearing and retainer disc.
very curious how this will work, but it made sense to me, comparing it to the old parts, that this will most likely be a little more stable than the oem construction.







so now i can start buttoning up the belt drive.



i guess there will be quite a few issues with the inner tin primary,
so at first i have to make sure the belt does not touch, and open up some of the bolt holes, too.





should i attach the inner tin cover to the frame, or just to the trans?
i'm thinking both, so i'll weld a tab to it and attach it to the frame at the upper rear end.

i had this neat handlebar clamp lying around, from a pan or early shovel i guess, and i really love the look. i would have to cut the bars i have on it
now to make it work, but i'm a little concerned about the clamp force being to weak to hold the bars in place, after all there's much more leverage force on it with the higher bars... anyone done this before?
 

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Discussion Starter · #80 ·
i have another question.

finally i had the kicker housing back on and i thought everything was fine.



but when i looked through the pictures i had taken during the assembly,
i found this:



i started worrying about the lock washer behind the nut that holds the kicker gear
on the main shaft. do i have to bend it or not?
i took the kicker housing off again and looked at the old washer,
that i had reused, and decided to get a new one.

i was told it has to be bent around the nut,
but i wonder why i doesn't have any "ears" for that,
unlike all the other lock washers in there,
and there's nothing about it in the manual...
how do you guys assemble this?

this is the lock washer, part #35 on the drawing



 
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