Dry clutch conversion

Sep 2017
281
2
Lansing Mi
Ok, so here we go. I'm committing to this.

You may ask "but why?". The 3 biggest reasons for me, 1- emotional, 2- why not and 3- THAT SOUND!!.

What I have learned so far, this is a pretty easy job for the 13-14 bikes. They share the same internal design as the 1098, 1198. Streetfighter, 999, 748.....basically the last generation of motors. The 13-14 use a separate bolt on oil pump assembly where the 15+ bikes have the oil pump cast n machined into the case itsself(notice differences in schematic pics).

This can be done on the 15+ bikes but need the clutch oil tube modified to clear the bigger 'knuckle' on the oil pump(the clutch cover comes in contact with that point of the oil pump).

My bike is a 13 so its 'Thundercats GOOOO!' for me. I mocked up the dry clutch cover and gears and it is all lining up perfectly. You need both primary clutch gear and secondary gears to make this work(I'm not sure about needing an oil pump gear off the 999 motor yet because the dry clutch gears mesh up perfectly in mock up).

I currently do not have a clutch for this conversion yet, I intend on getting the Kbike slipper but might juts grab a used clutch for really cheap just to get it going.

You may notice that the oil site glass is in a different location to the OEM hypermotard piece. It looks like they are parallel with eachother and the ground. I will watch the window as I fill it up and take note of what it takes.

This all started because my OEM pressure plate cracked. I reached it with a billet Ducabike pressure plate. So far it is holding up but during mock up of the dry system I installed stiffer Barnett springs and expect that the Ducabike plate will fracture too. I also have the judder spring kit. I installed it a couple years back and it made the OEM clutch more predictable and live-able in daily life(this is my daily driver). . I converted to hydraulic clutch actuation. I also have a rapidbike quickshifter. I installed the stiffer springs because it feels like it is slipping while hammering the quickshifter. Now, to break it all down, the slipper assembly was engineered to work with OEM springs and without the judder spring. I believe that judder spring (along with age, I have 17k miles on the bike) created the slipping. Adding the stiffer springs should help eliminate slipping but now the slipper springs are impacted by the change. I believe it to be a tension balance between the springs.

This is what I have learned so far. I will continue to update as I progress.
 

Attachments

Sep 2017
281
2
Lansing Mi
Notice the wear on the ducabike pressure plate. There is only about 2k miles on it.
Notice the differences in Barnett spring and OEM. Its subtle but they are slightly thicker(and only like $25).
Notice the fractured OEM plate. 2 of the spring pockets are fractured at the end and around the cup

I also did the factorypro detent shift mod about 2k miles ago. It requires more force to shift bit it definitely locks into gear with every shift. It has a stiffer spring, smaller roller and ceramic bearing. It almost eliminates all false neutrals. Although, while being lazy shifting I have hit a false neutral between 5th n 6th a couple times still.
 

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Sep 2016
341
1
ABQ NM
Then that's better than the cast one from the factory...please keep up the project, I'm anxious to see how it comes out...
 
Sep 2017
281
2
Lansing Mi
Everything is dry fit(minus the primary gear) for my dry clutch conversion. The clutch is a kbike slipper. The output shaft on the 821/939 is shorter than a normal dry clutch bike so the hub of the new clutch needed to be turned on the lathe to accept the make shaped nut that recesses back into the hub(every kit comes with the hub machined and a special sealing nut) That nut I'm using comes from the 1100 hyper as well as a few other bikes. One thing that messed me up 2 times now, in all the kits you see on line(the 3 kits that are available) show a splined primary gear. The 821/939 has a tapered fit keyway retainer gear. This needs to be taken from the 916 or 1100 monster/hyper. The 1100 hyper EVO clutch gear is drilled to make it lighter. It drops the weight by a half of a pound. If you are doing this pay attention to the primary gear, the 821 and 939 are NOT splined.

The next big obstacle (or so in was thinking it would be). How to seal the clutch pushrod within the output shaft/clutch hub shaft. All the kits use a super fancy special nut that recesses into the clutch hub. The nut also retains a seal in the end of the nut. Come to find out, part number 93040491a is a seal, part number 70250441s is needle bearing and 96855009b is a shim tube that the seal and bearing press into then the whole assembly presses into the output shaft/clutch hub shaft. That supports the pushrod on the clutch side and seals the pushrod(normally oil flows through here to lubricate the wet clutch. We are switching to dry so this needs to be blocked or else it will dump oil out the middle of the clutch). This bearing, seal and shim is a very snug fit. I'm confident with its hiding and sealing abilities.

The kbike slipper clutch I got requires a beveled nut that allows the center spider diaphragm spring to flex,. It has a shoulder that doesnt clamp it ruggedly to the hub. The clutch comes with 2 nuts(some bikes use a smaller threaded nut. I was able to take one of the nuts to the lathe and turn it into a washer/spacer which will hold and allow the spring to flex as intended. This was a big relief to me. I was thinking I would need to make a crazy fancy sealing shoulder nut as supplied in the kits. As it seems right now, all the stressful pieces are worked out.

Next obstacles, I needed to switch to the longer push rod. Luckily when I switched to the hydraulic pushrod system I ordered all 3 lengths made(all used. Only ~$10ea. I'll give an actual length when I finish assembly).

One thing to note, I needed to go to the local bolt supplier to get new bolts for the dry clutch cover, the wet clutch cover bolts have a flair at the base that doesnt allow them to fit into the recesses in the cover. $8 for all allen head bolts with locking washers grade 8.

I am set on running that lightened clutch gear. I have ordered 3 sets now. 1 from a streetfighter(lightened clutch gear but splined primary gear 59 tooth $ 32 tooth)one from a monster s4r (solid clutch gear 59 tooth and 32 tooth splined) and now the new one that is on their way here, from a st4/916 (solid clutch 59 tooth and TAPERED 32 tooth. I'm hoping to use the 59 tooth streetfighter clutch gear with the 916 primary gear). The best way to go about this would be to find a 1100 EVO motor clutch gear and primary gear set but it's rare to find.

Anyways, that's where I'm stuck till the new gear gets here, a week from wednesday. You may ask "why do this". For me it is for emotional reasons. I have always wanted a ducati with a dry clutch. Also, this is a hooligan bike. Dry clutch SCREAMS hooligan. The next question is usually "why not just buy a kit". The kits range from $2400-4000. I will have less than $1000 into this including all my trial and error. I intend on putting a full parts list together of what is needed once I'm done.
 

Attachments

Sep 2017
281
2
Lansing Mi
I have a bunch of other pics but it is saying they are too large to upload even though I tried screen shotting and resizing but no success. I'll upload more as I am able too