16T on Model 99 Toad Problem

[Alpenglo]

I just installed a 16T countershaft sprocket on our 99 Road Toad and found that there are clearance issues.
We are using a Renthal R1 428 non-O-ring chain. We used this same chain with a 15/56 sprocket set for the last 2000 miles with no issues but wanted a little more top end and so ordered a 16/54 as the 16T was listed as available for the Toad.

Has anyone else run into problems or had successes with the 16T on the Toad?

Thank-you,

Peter

[Zyx]

I think nearly any 100 or 125 Hodaka running that large a front sprocket will have clearance issues. Mostly, the chain drags on the lower case screw boss. I know mine does on 97 cases which have about the same screw placement, if not identical. What is the specific clearance problem with yours?

[Alpenglo]

It misses the boss but seems to have interference when I reinstall the outer cover. Likely the chain is too wide.
I'm putting a 15T back on, but would like to know if anyone has had success with a 16T on a Toad or similar.

Thanks-
Peter

[hodakamax]

Hey Peter, 16s are always close but should work. Try to see where it's making contact, probably the sheet metal inside cover. The covers are rarely pristine and may be deformed. You may be able to reshape it to fit your situation.

Hope this helps!

Max

[hodakaguy]

Hodaka lists the 16T sprocket in the parts list and uses a 428RK chain. If these are the right parts, something else is wrong.

[Zyx]

I have found that just because the part is listed as an option does not guarantee it is a drop in fit. You have to figure that if a 14 was standard, a 16 is a significant jump and would rarely be used except in specialty applications. Special applications usually imply custom fitting or someone willing to make adjustments to achieve an end. My chains have always contacted the steel liner over the screw boss even when using 14T sprockets, and the 16 I am using currently definitely hits the liner. But it is self-clearancing just fine so I will leave it for now. Side contacts are not right. I have run 428 chain in 420 applications without issues. Perhaps something has been left out. Do the sprockets line up with each other, or are they side-stepped away from each other. Dead straight is ideal. Angled is not. If there is an angle that is causing side contact with the case, you may have mismatched parts, possible in the rear wheel, not the countershaft sprocket. Inspect carefully and think outside the box on this. Sometimes the rear axle spacers don't get the job done and need custom fit. Mine do.

[Alpenglo]

Thanks for the tips but this bike is in really nice shape and was rebuilt with a new sheet metal inner cover. The chain makes contact just by placing the cover back on before there is any alignment concerns. With the cover on, I could only feed the chain halfway or so into the case before it bound.
I've put the 15T back on and all is well.
I'm pretty sure the Renthal R1 428 chain (non-O-ring) is just too wide.
If someone is running the 16T successfully, I'd be interested in knowing what the maximum outside dimension of of their chain is, that would be measured at one of the pins of the master link.

Thank-you,

Peter

[Zyx]

Sounds like something isn't right. The sprocket should roughly center between outer case and inner case, and 428 of any build should fit with room to spare side to side. But, it is doesnt, it doesn't. If the sprocket is displaced to the outside of center, the backing collar can be shortened, but would need to be done carefully so it stays square to the sprocket. Other than that, I guess I would have to see it to know if there is something else going on, and just where the contact is. If it is the pins hitting, then nobody's 428 is going to work well, and that makes little sense. The first point of contact on a larger sprocket should be the extreme edge of the link, not the pin.

[hodakamax]

It appears that the Model 93 and later had a recessed center on the countershaft sprocket where the previous models had a flat one. I'm just wondering if there could be a mix up here causing the problem. Just a question, as AZ says, something's not right.

Max

[Alpenglo]

I would now agree with AZ regarding the first point of contact being the edge of the side link and not the pin.
I'm guessing it must be touching in the radiused area of the tin cover. Next step was to coat the tin cover with a marks-a-lot to see where the contact occurred but it was time to get the bike back together and go riding.
We have 2000 miles on the last chain and sprockets and they showed no wear from misalignment.
We just put 150 miles on our Hodakas in the last two days with no issues with the 15T (as in the previous 2k miles) so we'll be sticking with that.
Thank-you for all the input, we do appreciate it.

Peter

[hodakamax]

Hey Peter, these Hodaka mechanical mysteries are fun, thanks for asking us--It keeps us entertained and on our toes!

Maxie

[Bullfrog]

Surely the chain was leaving a mark on something?

Note: The newly manufactured steel inner covers are not EXACTLY the same as the OEM units. Slightly different radii on some of the formed sections . . . that might allow/cause interference which was not there with the OEM steel inner cover.

Ed

[Zyx]

I would give consideration to making adjustment to the liner. Should be easy enough to tap out the area of contact to make clearance.