90cc and 100cc final drive sprocket spline dimensions

[Barndweller438]

Thanks for accepting me into Hodaka Club Forum!

I am hoping that someone with calipers could provide me with the countershaft spline dimensions of a drive sprocket from a 90/100 cc bike. I need three dimensions of the splines; the maximum ID, the minimum ID and the spline crest width. I am also curious if anyone has cross-referenced sprockets from other bikes that fit Hodaka's 90/100s?

[JPark]

You'll find lots of countershaft sprockets for Hodakas at hodaka-parts.com. Also the nut and the lock washer. There's not much chance of any cross reference and no need to when the original parts are still available.

Rear sprockets can be a challenge. Plus there are four hole and six hole types and 420 and 428 to consider. You won't get 420 chain on a 428 sprocket and 428 chain on 420 isn't a proper fit either. The centre hole does have a few matches at JT Sprockets but the bolt hole pattern will often need to be redrilled. The later hubs are 62mm hole and six holes on 80mm. I don't have the early 4 hole hub numbers on hand.

[Barndweller438]

Thanks for your response JPark! I have Hodaka parts mixed in with other bike parts. I believe some of the sprockets I have fit the smaller Hodakas so that is why I was asking about the spline dimensions. I incorrectly asked for the spline crest width. The dimension I need is the width of the valley of the maximum ID, if that makes sense. Wish I could attach a drawing of a sprocket for clarity. Still hoping someone has a sprocket laying around that they can measure.

[JPark]

The spline is just a 4mm untapered groove in the sprocket. The ID is 16mm and the OD is 20. So the height of the spline is 2mm. Just a 2X4, ha ha.

The countershaft in hand is an Ace 100 and the sprocket is a new 428 one for a model 02 Road Toad and they're a fit. I don't think anything happened here over the years other than the early 90s which switched from a snap ring retainer to a nut and bend-to-lock washer.

Given the 6204 output bearing having a shaft diameter of 20mm, the possibility that these sprockets would be similar to some other bike is not improbable. The numbers 2,4,6,16, and 20 don't look like they were trying for exclusivity.

[taber hodaka]

The ace 90 did not have a snap ring on the counter shaft part number 904601 and it used a nut. The ace 91 racing transmission used the snap ring with part number 904601R. The ace 100 model 92, 92A, 92B, 92B+and super rats model 93, 93A 93B used a counter shaft with a nut, part number 924601. ------------- Clarence

[dirty_rat]

If you go to the JT Sprockets website, it shows the dimensions of their sprockets, both front and rear. The front sprockets that fit the Hodaka countershaft are as follows.
420 chain: JTF 413, JTF 546
428 chain: JTF 416, JTF 417, JTF 418 (there are more)
520 chain: JTF 422

As far as rear sprockets, the ones that have the same dimensions are the following:
428 chain: JTR 1842
520 chain: JTR 845, JTR 1845

[Barndweller438]

JPark, thanks for sharing the dimensions of your countershaft and sprocket! The 20x16x4 splines matches some of my 420 drive sprockets.

dirty_rat, thanks for identifying the JT Sprockets that fit the different chain sizes used by Hodaka. I was only aware of the JTF546 because it matches my sprockets that I suspected might fit the smaller Hodakas. I have found JT Sprocket's website to be very helpful many times.