Machinist Help - Slipper Clutch Concept (yes, again)

[riot]

Paging DrPMC, wildwhl, and eyhonda for advice:

I'm sure this thread will get buried 2 pages down by some tractor carb controversy, but here we go anyway:

In short, I have been able to determine that the CBR600RR friction plates (not steels) are identical to hawk friction plates. Further, there are quite a number of clever clutch system options for CBR600rr and its relatives, which could provide some attractive performance upgrades to old Hawky.

The strategy is to utilize a CBR600RR clutch center (perhaps a slipper clutch center) with the Hawk outer. Of course, nothing is a bolt on. Specifically, I need to find a way to adapt the smaller splined shaft of the NT650 to the larger spline of the CBR:

20220909_171806.jpg

There are basically 2 options:

1. Machine an adapter with the inner for the hawk and the outer for the CBR (see dims in the pics) - the difficulty is figuring out which exact fit/type the spline is (ANSI, DIN, JIS?) and having one made.
2. The Hawk spline is a pressed-in steel insert, I could extract it and machine the CBR plate to take it. This is a very cost effective solution, but I am worried about strength. Plus I have to permanently sacrifice the parts.

There will be possible other issues, like clutch stack height etc., but I think they are solvable. The main thing is getting the center adapted in an elegant way.

Any advice? Volunteer to help? I am happy to send some parts if you'd like to have a go...

[wildwhl]

Looks like a fun project - but I have too many more funnererrrrerrr projects (aka those that make money) right now to tackle something like this.

With lack of coffee in my brain yet, and just at a glance without my glasses on (yes, I'm getting that blind) it would seem maybe machining out the center of the CBR part (to match whatever the OD size/shape of the NT part is) and pressing in the splined insert of the NT part might work. Of course, there has to be sacrifices made if the virgins are to pass into the slipper clutch realm

WW/R

[riot]

Looks like a fun project - but I have too many more funnererrrrerrr projects (aka those that make money) right now to tackle something like this.

With lack of coffee in my brain yet, and just at a glance without my glasses on (yes, I'm getting that blind) it would seem maybe machining out the center of the CBR part (to match whatever the OD size/shape of the NT part is) and pressing in the splined insert of the NT part might work. Of course, there has to be sacrifices made if the virgins are to pass into the slipper clutch realm

WW/R

C'mon man. this could be a cool new category of Hawk Mods for you!

Yes, I think the press method is the way to go too, but I am not super confident using my crappy tools (ancient lathe) that I can get the fit just right. For someone with the right tools though, it is probably way easier than getting 2 mystery splines to fit correctly.

[wildwhl]

C'mon man. this could be a cool new category of Hawk Mods for you!

I have exactly 1 Hawk GT project on my books/left in me, and it is very cool. I'd bet it is cooler than this - and it is at least more intriguing to me than a slipper clutch for a bike that truly doesn't need one (my opinion). There will be a limited run (<10 pieces) and will never be made again. That's all the bandwidth I have right now for bike parts. The rest of the motorcycle bandwidth is for riding - and I intend to continue getting 200+ mile rides in every weekend as long as there's no snow on the roads.

When I'm not riding or working weekends, I'll continue whittling the 95 lb hunks of 6061 into a pair of <40 oz gems like no other

WW/R

[riot]

I have exactly 1 Hawk GT project on my books/left in me, and it is very cool. I'd bet it is cooler than this - and it is at least more intriguing to me than a slipper clutch for a bike that truly doesn't need one (my opinion). There will be a limited run (<10 pieces) and will never be made again. That's all the bandwidth I have right now for bike parts. The rest of the motorcycle bandwidth is for riding - and I intend to continue getting 200+ mile rides in every weekend as long as there's no snow on the roads.

When I'm not riding or working weekends, I'll continue whittling the 95 lb hunks of 6061 into a pair of <40 oz gems like no other

WW/R

Fair enough, can I just sign up for one of these parts now then? if you need to make 11....

[wildwhl]

Fair enough, can I just sign up for one of these parts now then? if you need to make 11....

No dibs. How did you like that thread jack?

[riot]

No dibs. How did you like that thread jack?

No worries sir, as long as your new invention doesn't turn out to be a side-mount carburetor

[wildwhl]

No worries sir, as long as your new invention doesn't turn out to be a side-mount carburetor

Dual 650 Holley double pumpers custom manifold under tail mounted - how'd you know?

WW/R

[6]

G'dam it WW. Epic teaser...

riotcool project! Does a hawk "need" a sliiper clutch. no. Would i absolutely LOVE one, especially an adjustable one, HELL YEAH. Hawks engine braking is strong, and consistent, nut i have definitely had lock ups when i dont want them on the track and im pretty good with that left hand lever.

eric is also getting out of the hawk machining game for the time being.....

I have an angle grinder... Will that help ? ? ?

Despite my lack of skill, tools and $, if i can help... Slipper along with a quick shifter has been on my list of wants for the hawk for ten years. Worthwhile project i feel.

[Luis]

Fair enough, can I just sign up for one of these parts now then? if you need to make 11....

+1

[eyhonda]

I think making an adapter is best method. Splines are broached, not really machined. I'm not set up to do it but maybe the Dr will chime in. Will need some sort of matching bits, a way to index the part and a way to mill cut it. A lathe is only good to get the rough piece. Actually, on second thought, a lathe might be good for holding it and then the bit holder for cutting the splines, a few thou at a time. The lathe won't be turning the piece, just holding it. Maybe put the indexing holding part on the tailstock? Just thinking out loud. I've never done it, just watched vids of it being done.

[rpm10k]

G'dam it WW. Epic teaser...

riotcool project! Does a hawk "need" a sliiper clutch. no. Would i absolutely LOVE one, especially an adjustable one, HELL YEAH. Hawks engine braking is strong, and consistent, nut i have definitely had lock ups when i dont want them on the track and im pretty good with that left hand lever.

eric is also getting out of the hawk machining game for the time being.....

I have an angle grinder... Will that help ? ? ?

Despite my lack of skill, tools and $, if i can help... Slipper along with a quick shifter has been on my list of wants for the hawk for ten years. Worthwhile project i feel.

I run a healtech quickshifter, it took a bit of fiddling with the delay time/sensitivity to get it dialed in but it works fantastic.

i'd love a slipper, though. following this thread with interest...

[DrPMC]

Obviously, without having the parts to hand its not possible to say anything for certain, but I would incline to transplanting the centre of the Hawk clutch into the CBR one. Making splines in the home workshop, hardening etc… tricky.

It might be necessary to roughly chop the Hawk centre out and then turn into an insertable part on the lathe. Even if the lathe isn’t perfect it will probably do. I think I might mount the Hawk centre on the mainshaft in the chuck, that will probably help to keep it true. The insert could then be pressed in and then either pinned in with some screws or welded.

Is there scope to securely hold the CBR centre in the chuck to bore it out?

I did my dry clutch conversion on a mini lathe which is about the worst lathe out there. It’s not perfect but I haven’t noticed any significant extra vibration. A clutch is a pretty crude thing really.

[squirrel_hunter]

This interests me as I have all the tools but not the experience.

Depending on the construction of the CBR clutch I'd look to modify to transplant the NT clutch. Using a lathe open up the clutch and then press fit the NT splines. But the CBR clutch doesnt have a slipper as stock from what I know so you'd have to modify an expensive aftermarket part. My thinking sends me to ask what other stock slippers could be used? In theory and simple terms a clutch is the same regardless what bike its used for. The considerations are size and shaft. Taking the shaft splines from this then so long as there is enough material to allow for modifying then pressing in the NT spline adapter is fine. The question then comes to size of the overall clutch to fit into the engine, diameter and height. Of course if you find that there is probably spring rates and other considerations I've not yet thought about.

But as I say, it interests me, but I dont have the experience...

[6]

I run a healtech quickshifter, it took a bit of fiddling with the delay time/sensitivity to get it dialed in but it works fantastic.

i'd love a slipper, though. following this thread with interest...

We had one rigged up, but had a lot or trouble with the switch. I don't use a shift linkage, drew built the circuit with an adjustable kill time that worked great, but the best we came up with was activating it with a rigged up rear brake switch, which never quite worked right.