iv got a 2000 plate dtr with 16000 miles on the clock (dont know if thats legit or not lol)
i have brought 2 piston kits in two months these are cheep ebay ones you can get for £22.
so the story goes like this brought the bike and the first thing i do is a top end rebuild not because it needed it just for peace of mind. and so i could see the condition of the barrel. the barrel is mint no scores not even a sign of a scratch anywhere. plug is a nice color too. so i put this cheap piston kit in KHC was the brand i think and was run in properly nice and gently for 400 miles.
3 weeks and 600miles later from the date piston was put it i lose most of the compression (kick start is flimsy and would only start by bumping later confirmed by a spark plug type compression gauge) took the top end off and the bottom ring had snapped but was still in its groves with only a 5mm peice missing i can only assume has been thrown out the exhaust port. so i brought another piston kit (rings,piston,gudgon pin,circlips) of the same brand and put it in, was in the process of running it in got to work ok with no issues.
go to start once i had finished work and kick start is flimsy again would only start by bumping it up the road. get home and tear the top end off, diddnt even bother testing the compression this time, to find the same failure that happened to the last piston rings
the bike has a standard barrel 56.00mm and a working powervalve. big end and little end bearings are sound no movement whatsoever.
would be worth adding the rings had failed exhaust side both times?
thanks in advance for and advice you can give me and anyone's previous experience with cheap piston kits.
Never buy cheap. Especially when it comes to engine internals.
But from reading your story I'd say that it wasn't cheap parts that failed you but perhaps a poor installation job. From going what you have said it sounds like to me you did not check the piston ring end gap and on both occasions it was incorrect and has resulted in the rings butting together causing them to break away.
I'm by no means no expert but that to me sounds like what has happened.
i have ordered a mitika piston kit from yambits so should hopefully be ok now.
all tho the ring had snapped they had remained in the grove both times so the barrel is still like new! was a surprise to me.
a friend of mine said that the cheaper rings don't contain enough silicon so as a result they are brittle and prone to snapping? is this true
i didn't check the ring end gap, one because i don't know how to correctly lol, and second i presumed because its a standard size barrel it wouldn't apply
iv never had any problems with piston rings snapping before on a new build ever. but perhaps i had make a mistake on Assembly once but twice i find hard to believe (not impossible though)
Na it will be the cheap piston kits. Mitaka use RIK rings still I think so you'll have some good rings in there now. I've always use mitaka on road bikes so far and never had a problem. I used one a motocross bike and it died very quickly and wrecked the bore plating. It's kinda put me off using them again but they were very different pistons.
Mitaka is basially the lower quality you want to use. Vertex, Wiseco, ProX are all good brands.
