Clutch sprocket advice required 1978 Jota 180

[Docho]

I'm stripping down the crashed Motodd MK1 I acquired a couple of weeks ago, the primary chain has broken as part of the damage caused during the crash, on investigation it was definitely single row. In the attached pictures the damaged chainwheel is obvious, I intend to use a double row chain in the future, full stripdown over the next few months as there was a lot of debris at the bottom of the case, nothing metallic in the oil fortunately.

The front sprocket looks fine.

Has anyone a used clutch sprocket I could buy as I don't think there are any options for repair!

Thanks, John.

 

[rez]

Hm, when i'm right,
u need a new Crankcase
( or an excellent Welder )

Rainer

 

[Paul Marx]

I'm stripping down the crashed Motodd MK1 I acquired a couple of weeks ago, the primary chain has broken as part of the damage caused during the crash, on investigation it was definitely single row. In the attached pictures the damaged chainwheel is obvious, I intend to use a double row chain in the future, full stripdown over the next few months as there was a lot of debris at the bottom of the case, nothing metallic in the oil fortunately.

The front sprocket looks fine.

Has anyone a used clutch sprocket I could buy as I don't think there are any options for repair!

Thanks, John.

Alan James will no doubt have that.
Paul

 

[Pauls]

If a used sprocket is available go that way. If not, and there is no other damage to the clutch drive other than to the teeth, it should be possible to use a duplex chain on the inside 2 sets. It might be a tidy engineering idea to have the outside damaged teeth machined off. Definitely a primary drive cover will be needed.

 

[alan james]

Hi, I have a very good clutch drum sprocket and a primary chaincase if that is needed. I will P.M you.
Alan.

 

[Docho]

If a used sprocket is available go that way. If not, and there is no other damage to the clutch drive other than to the teeth, it should be possible to use a duplex chain on the inside 2 sets. It might be a tidy engineering idea to have the outside damaged teeth machined off. Definitely a primary drive cover will be needed.

I had considered that however typically 1 of the teethe on the middle ring has been nipped! Will investigate further.

 

[piranha-bro2]

And check that the gearbox mainshaft isn't bent. Taken a mighty whack ... no doubt slid top-first into a kerb or similar.

 

[1200ts]

The last time I saw a triple have a bad crash on the primary side like your bike, both the crank and main shaft were bent. Bike slid along the road until the primary cover hit the street curb.

Left crank web and main shaft had to be replaced.

 

[breganzane]

Good news is that both those shafts are easy to check for straightness without full disassembly. Just put a dial indicator on the end of the shaft and rotate. I would also want to check the outer clutch drum for any runout.
It's some gnarly damage, thats for sure.
The mangled primary cover is a great trophy to screw on the wall... 'offerings to the gods of speed' indeed.
Good luck with the work, keep us posted.

 

[Docho]

The last time I saw a triple have a bad crash on the primary side like your bike, both the crank and main shaft were bent. Bike slid along the road until the primary cover hit the street curb.

Left crank web and main shaft had to be replaced.

I’ll check them both, will be a complete strip down.

 

[Docho]

And check that the gearbox mainshaft isn't bent. Taken a mighty whack ... no doubt slid top-first into a kerb or similar.

Car trailer apparently

 

[Docho]

Good news is that both those shafts are easy to check for straightness without full disassembly. Just put a dial indicator on the end of the shaft and rotate. I would also want to check the outer clutch drum for any runout.
It's some gnarly damage, thats for sure.
The mangled primary cover is a great trophy to screw on the wall... 'offerings to the gods of speed' indeed.
Good luck with the work, keep us posted.

Thanks for the advice, apparently it hit a car trailer, needs frame repair as well. Will post a few pics as work progresses.