So a few weeks ago on the drive home my bike started making a strange noise and running really rough. After dropping the oil and noticing shavings/teeth in the mix I began to strip the bike down. I found that the gearing which connects the outer clutch drum to the crankshaft has shredded itself. I've attached some pictures to help explain what I mean and where on the bike I'm talking about. Before I dig in an really rip the engine apart I guess my questions are: A) Does anyone know why this would occur? - I don't want to fix it to find the ultimate cause is elsewhere. B) Is the affected gear on the crank removable or does it mean a whole new crank? C) Is there a specific name for the gear involved? If it turns out I'll need to buy a new crank then I may need to reconsider fixing it as it may get too expensive. I know its going to be a big job anyway with skimming the casing and helicoiling the exhaust bolts but considering its my first big boy bike I'm going to put in the effort and try to fix it. Any tips or considerations are appreciated. Bike Info: 2007 Triumph Daytona 675 40k miles (ish)
That’s the backlash gear ⚙️, They are prone to breaking on hi-mileage or race engines. You don’t actually need it. It’s literally only there to quieten things down on road bikes. I have 2 engines with them completely machined down. I’ve enquired about getting another done like this & machine shop say they no longer can. So you can just replace the clutch basket which has the backlash gear attached to it & rebuild it. You just need to pray that none of the pieces of the old backlash gear did any damage inside the engine while the engine was running. Personally I think I’d have the engine rebuilt to be safe, at 40k it’ll benefit from a refresh & once done, assuming you use someone that knows the 675 well, your motor will be as fresh as the day it came out the factory. I’m pretty sure I have a couple of the said clutch baskets with the backlash gear on if your looking to purchase one?
I just want to make sure I'm understanding you correctly as I'm a little out of my usual depth. So you're saying I can just replace the clutch basket with one that has no backlash gears on it and then just leave the crankshaft backlash sprocket in place? When looking both sprockets (clutch basket and crank) it looks as if there are 2 separate sprockets on each side. Is this one piece or is the backlash gear just one of these? I've added a close up photo of the clutch basket incase I'm not making any sense. The larger section of sprocket on the crank isn't in a good shape either. I also agree with your suggestion of getting it completely rebuilt anyway, I don't suppose you know anyone near Newport/Cardiff/Bristol to get this done? Unless you do this yourself?
Hi, I think i have the same issue. Think because i didn't look myself into it, but looks similar to my mechanic s description. I went to the garage to change the camshaft chain when they discover this as well. My opinion is, a piece of the blade that tender the chain posibly broke down and went into the gear. My bike reach, 65 000 km, so basically same as yours. Get the cam shaft checked at first i think.
Will need a new crankshaft , clutch basket and possibly a new balance shaft looking at the state of the teeth on the crank
