[ScottR]

Does anyone know if the speed 400 has the same rear sprocket or is it different from the 400X??

 

[ScottR]

I just installed the JTF1908.15RB sprocket from SO CAL Powersports $18.98 to the door. It fits perfectly, I still do not think a 16 tooth will fit under that wiring guard, but heck who knows somebody will figure out something if they can find a 16 tooth sprocket that is. Pouring rain test drive coming soon. View attachment 49
View attachment 48

This looks like a great solution to start with. I've never pulled off a front sprocket - would you mind detailing the procedure you went through? Thanks much!

 

[ScottR]

I used a bike lift table, ez on the old back. Fairly simple procedure. Remove sprocket cover on right side, then the clips holding the wiring harness to the sprocket plate (they tough little buggers to release). Next remove both bolts holding the metal sprocket cover to bike. Once the plate is out of the way you can access the sprocket main nut. Can’t remember size right off, but put bike in first gear bend the safety washer tab out with flat screw driver and remove nut. I used electric powered impact drill. Spins right off, now I loosened rear axle nut, jacked bike up with scissor jack. Put bike in neutral ran rear chain slack adjusters all the way in on swing arm. Your chain will have plenty of slack now. Very carefully remove sprocket off shaft, tap lightly while pulling off. Pretty snug fit. Tip: roll the rear tire to get as much slack toward that front sprocket wedge piece of wood under tire so your chain slack will stay put. The chain will be stiff since it’s brand new but you can remove it off sprocket and install new one same way. Reinstall everything same way In order as you removed. Not super ez but takes time and don’t forget to bend tab back down on that sprocket nut. I didn’t have the torque spec for that sprocket nut so I torque it to what I thought would be close. Remember that bent tab will keep nut from rotating, user your best judgement. Research forums for triumph motorcycles. Since this is the only thumper they make any torque spec you find on 660-900cc should work just fine. They have much more horsepower. As far as alignment of rear axle I used micrometer to set slack adjustment on both sides exactly at the proper tension of course. The torque spec for rear axle in in the owners manual. Can’t remember what is was. I’m old fellas. I’m not a certified mechanic but been riding motorcycles since gasoline was .75 cents a gallon. Good Luck, if I can do it you can do it!

Thanks so much for all the details.

 

[ScottR]

I just installed the JTF1908.15RB sprocket from SO CAL Powersports $18.98 to the door. It fits perfectly, I still do not think a 16 tooth will fit under that wiring guard, but heck who knows somebody will figure out something if they can find a 16 tooth sprocket that is. Pouring rain test drive coming soon. View attachment 49
View attachment 48

Curious, how did you determine that sprocket would fit the front? I talked to Paul at So Cal for other options and he didn't show any listings for the 400X