as noted elsewhere, the countershaft or drive shaft splines can wear prematurely on the 70 degree bergs and ktm exc models. it seems the steel of the shaft isn't always that hard...
i was thinking of trying the dirt tricks washer but essentially it just looked like a stronger version of the stock dome washer.
so a friend suggested welding two washers together. he figured if the bottom one was very broad then it would make good contact with the sprocket and hopefully stop it moving on the countershaft/drive shaft. he also suggested a longer bolt to make full use of the thread, a 10mm spring washer and loctite.
it's not a great photo but you can see the spot welds to join the two washers together. i made some marks with permanent pen to see if the sprocket would still move and possibly start to loosen the bolt off. the obvious risk with this mod is if movement eventually caused the bolt to drop off, the front sprocket to come off then possibly lock up the rear wheel and/or crack the engine case. 8O
on the first ride the sprocket did move slightly but on all subsequent rides it hasn't budged. i'm still checking it repeatedly during rides until i'm 100% convinced it's anchored in place. just keeping a 17mm spanner handy in the pocket to check every hour or so during dirt rides!
so the theory is if the sprocket isn't moving in relation to the actual shaft then it can't wear out the splines. if it continues to work then hopefully this is good news for anyone planning on clocking up a lot of miles on their bergs.
for the record, other suggestions made have included:
- run a cush drive hub for road use or adventure riding
- make sure your chain is never too tight
- don't use sprockets with that are harder than the shaft itself
- keep a constant eye on sprocket/spline wear and replace the front sprocket frequently
- dual purpose tires might increase wear (no knobs means no flex which provides a bit of cushioning)
- use a high temperature grease on the splines.
i was thinking of trying the dirt tricks washer but essentially it just looked like a stronger version of the stock dome washer.
so a friend suggested welding two washers together. he figured if the bottom one was very broad then it would make good contact with the sprocket and hopefully stop it moving on the countershaft/drive shaft. he also suggested a longer bolt to make full use of the thread, a 10mm spring washer and loctite.
it's not a great photo but you can see the spot welds to join the two washers together. i made some marks with permanent pen to see if the sprocket would still move and possibly start to loosen the bolt off. the obvious risk with this mod is if movement eventually caused the bolt to drop off, the front sprocket to come off then possibly lock up the rear wheel and/or crack the engine case. 8O
on the first ride the sprocket did move slightly but on all subsequent rides it hasn't budged. i'm still checking it repeatedly during rides until i'm 100% convinced it's anchored in place. just keeping a 17mm spanner handy in the pocket to check every hour or so during dirt rides!
so the theory is if the sprocket isn't moving in relation to the actual shaft then it can't wear out the splines. if it continues to work then hopefully this is good news for anyone planning on clocking up a lot of miles on their bergs.
for the record, other suggestions made have included:
- run a cush drive hub for road use or adventure riding
- make sure your chain is never too tight
- don't use sprockets with that are harder than the shaft itself
- keep a constant eye on sprocket/spline wear and replace the front sprocket frequently
- dual purpose tires might increase wear (no knobs means no flex which provides a bit of cushioning)
- use a high temperature grease on the splines.
