ptxyz

finally have resolution to this. not exactly what i'd asked for but, i'm satisfied, given the damage was minimal. jt rep. i'd been in email communication with asked that i call this morning. from the gist of it, they're unable to determine the exact cause of failure. they found no problems with the rest of the chain and suspect some problem with the single pin that sheared. jt will pay me $250 and a future chain / sprocket set. i'll use that set on my klr650 or new to me xt225. no more less that top tier drive products for the blackbird. i've never been too picky about my chains. cheapest i've used was a $50 volar that lasted all of 3-4k miles before stretching to the limit of adjustment. never expected this type of failure. i'm now more careful of situations where the rear might regain traction abruptly (like slippery manhole covers and dry pavement). not sure if i could've reacted quickly enough to the sudden loss of drive and increase in revs that accompanied this failure and prevented the damage to the lower engine case but, it's something i'll always think about going forward. hope this helps someone else avoid this whole hairball...

the jt front sprocket that was on my blackbird when i had the chain break a few months ago had more play on the splines (in and out from the bike centerline) than i'd ever seen on any of my bikes. i'd avoid any of their products.

sorry i didn't read this sooner. you can, by removing the 3 or so bolts and 1 plastic push pin closest, leaving the rest. it's a bit of a stretch (of that lower) but, it's a good idea to remove and clean the clutch push-rod too.

good suggestion, companies are loathe to dispense cash... while i'll never put another of their chains on my bird, i might take one or two for my klr if i think that's all i can get from them...

small update, jt's asking for a dollar amount without saying they'll pay yet. i'm figuring a full refund of the defective chain sprocket set to start ($179). i had to order a rear hub, ebay used ($29). i spent about 4 hours total repairing the case with epoxy (seems to be holding) and replacing the chain and sprockets. my time's worth something and even @ say $50/hr, way cheaper than a shop. do you think $400-500's reasonable?

finally put the bird back together and went for a test ride yesterday. refitting the sprocket cover was fun, seems the bolt holes are not quite in the same place. i also needed to shave that thick metal "gasket" that's between the cover & case, it was touching the clutch pushrod. clutch action is, thankfully, smooth. in one of my better recent moments of "i can't believe i fucking just did that...", i took out too many links to use my fancy 46 tooth supersprox rear... thankfully, the used ebay hub i bought (discovered the old chain damaged a couple of the sprocket mounting nuts / studs on it's way out) had a nice sunstar 45 tooth sprocket. i'll be back to stock gearing (17/45) for this chain... still no word from jt on the failed chain. pressure will begin to be applied.

thanks! while downtown san jose has it's charms, like plenty of bars, restaurants and other entertainment venues, it's being overrun by the mentally ill and homeless. there are also scenes like this on my way to work... was she trying to tell me i have a hot dog hanging out of my mouth?! no progress on the blackbird last weekend. had to chase down a parasitic electrical draw (& replace a 6 year old battery) on our '98 e430. turned out to be another hvac blower motor resistor gone bad... no word from jt regarding their inspection of the chain but, it only arrived to their lab friday...

ha ha! ok, now i get it! i could be accused of being an amateur reader and slow on the uptake too, just ask my wife! jt has requested their chain back and tells me they want their lab to test it. stay tuned...

hey, i resemble that remark! seriously, that's why i'm here... what would have been better to use?

carb cleaner in a spray can

i've cleaned and used jb weld to put that chunk back in place. chain and sprocket should be arriving this week (already have a new front, this one fits pretty tight unlike the last...). also been in email communication with someone at jt. after seeing the marginal quality cell pics, same i've posted here, they'd like better pictures and details about the bike, install etc. hopefully, the lack of receipt on ebay purchases won't give them an out. it's promising they also want to see damage to the bike. i'll keep y'all posted.

jcrich, your thoughts on the now 2 bolt sprocket cover? will they be enough?

just got a better look at the damage... sorry, the rear sprocket damage is kinda blurry. you can see a gouge in the swingarm and one of the nuts. marks from the chain on the sprocket cover's inside. chunk where one of the cover bolts goes broke it's threads out... does the community think the remaining 2 bolts will hold? don't see damage to the sprockets. i'm debating just getting a new good quality chain or should i replace the sprockets too? if i go the later route, i'm thinking spring for a supersprox rear and oem front (17/47). this jt front has a bit more play than i'd like...

had a close look at the rear sprocket, only damage i can see is from the chain getting caught up between it and the swingarm (locked my rear wheel, that was fun...). sprockets and chain were replaced back in may, not sure of the exact mileage but, not more than a few thousand. one trip to laughlin and 20 mile round trip commutes (shared duty with my klr). watched my gopro footage and don't see any debris on the pavement leading up to this. haven't yet noticed any missing fasteners or debris from me that might have caused this, i'll get a look at the front sprocket this weekend. i'm hoping i just have to replace the chain. other side of the pin looks just like the visible side. appears to be a pretty clean shear. so far, i'm inclined to believe it was the shock of regaining traction suddenly that caused a defective pin to fail. here's a screen grab from my gopro showing that slippery manhole cover... how fortunate work is only about 50-60 yards beyond! "why the hell is that idiot pushing his bike down the sidewalk and through the crosswalk?!"

preliminary investigation reveals a sheared factory pin! i'm somewhat relieved it wasn't my master link installation... oh, and it appears to be a jt z3 chain...