Has anyone run across one of these, 25 Tooth engine sprocket? Caught me out!
Went to change the primary chain, and nothing fitted back on, chain too short, had to go
down to a smaller sprocket, now waiting for the new chain to stretch to get the 25 back in.
I'm running a 23 for a fill in, whow! it's so low.
If you look closely at the shot you just see a little of the old 55A part number.
And the weld. Nice job.
My parts book only lists a 24 tooth as the biggest you can get.
Has anyone run across one of these, 25 Tooth engine sprocket? Caught me out!
Went to change the primary chain, and nothing fitted back on, chain too short, had to go
down to a smaller sprocket, now waiting for the new chain to stretch to get the 25 back in.
I'm running a 23 for a fill in, whow! it's so low.
If you look closely at the shot you just see a little of the old 55A part number.
And the weld. Nice job.
My parts book only lists a 24 tooth as the biggest you can get.
Pete
Maybe its just the angle & flash, but that motor sprocket looks like some of the hights on the teeth seem real short compared to others! Could be my PC---anyway check it out, dont mean to raise any alarms!(good-Luck)58flh
The '41-'54 "Spare Parts" lists a 40212-30 25T motor sprocket as (Special).
Note that it also includes 17, 18, 19, 20, and 21 tooth variations!
I have only encountered small sprockets upon VLs, but I am sure there is a time and a place for them on a Pan. You never know when you may want to tow a barge.
Goin up on the tranny sprocket will make up for goin down on the motor sprocket, but I don't think you can go big enough on the trans to make up for droppin 2 on the engine if you started with a 25 on the motor. I've seen 26T tranny sprockets but I don't think you can run a 26 with a ratchet lid, but it should clear a jock top. If yer gonna wait for the primary chain to "stretch" so yer 25T motor sprocket will fit, yer chain is gonna worn out again, I would think....bosheff
I don't think that is a factory item. All the compensator type sprockets I am aware of came in 22, 23, and 24 tooth configurations. All the other sizes were solid type only. and all the compensator types I recall were machined in one piece, not with the teeth welded on like yours. And theweld obscures the part number, not factory practice. I have a couple 25 tooth solids around here that I ran on strokers years ago. I'll have to look in the shop tomorrow and also check the books but pretty sure yours is a one-off item. And the sprockets Cotten mentions were all tapered shaft types. The really small ones were never made for splined shafts. With the big center hole the teeth would be floating in the air! The small ones were primarily used for Hill climbers and endurance events. Also on package truck equipped bikes where 19 tooth types were often specified.
Robbie
Now that I can view the pic on my wife's broadband, I see that its weld is substantial!
It would require controlled heat-treating after the weld, or the teeth would be like mud.
If the Factory saw a "special" need for them in the tapered shaft era, there is reason to believe they might in the splined shaft era as well.
Pete,
Thanks for this post and Picture!
I've been wanting to modify one of my tapered shaft compensator sprockets up to a 25 tooth, and I was going to do exactly as you have pictured. Glad to see that is is possible!
I ran a solid 25 tooth for a few years, but used to "eat" primary chains (stretched beyond use) after just 1K miles or so.
I went ot a 23 tooth compensator (Biggest I can find for a tapered shaft motor) to keep the chain life, but I would like to run the ratios like I used to.
I also used to add two links to the new primary chains to get them to fit the 25 tooth. (Punch out the pin, and peen in two links).
I know that I could run a belt to get the ratios, but I am cheap and the chains are forgiving on alignment, and I never broke one yet.
- Dave
G'day
58FLH, No worries! No shes a good one, just the shot looks strange.
Steve, I may have to go 24T as 23 is driving me nuts. That chain stretched initially but
has pulled up now, I don't think its gonna stretch much more as Bosheff said. I even had to run
my chain tensioner in the low position (65).
Cotten, you're right on the heat treating, and this one is hard, been on there 12 years hardly any wear on it. Good info thanks!
You gotta love that broadband Cotten, go on,.. ditch the dial up. I know you dislike some modern stuff. We all resist it!
Robbie, good info as usual, thanks!
Dave_R, now you got me thinking, I did try a longer chain I think it was 84 link, I know it was a baker drive train chain, but it was too
long and the standard is to short (82 link), so i was stuffed (catch 22 I think), or rock and hard place. Solid sprockets eating chains, shit
I was gonna go with a 24T solid, I have found a good one for $24. I might rethink that.
