KDXRIDER.NET

Hello.. havent been here in a while.. mostly cause work has the forum blocked (LAME!).. but also I did a top end job with a bunch of trick aftermarket stuff and f*ed it up!

So I did the rb head and carb mod, mototassarni reed/block, had the cylinder replated at langcourt and dropped in a new wiseco...

I put everything together and gave her a few good kicks and it started right up. Went through my own break in period of maybe 3 or 4 rides. I then started riding the bike like normal, trying to focus on not overrevving and that kind of thing.

Well I went for a short ride one day (by myself of course) and was riding up a hill and the bike just felt down on power so i shut it down. I went to start it and compression in the kick start was really low and around idle, it sounded like there was peices of metal in the cylinder dinging around (probably was!!!) So I limped back to my house and shut it down knowing I totally f*ed up something.

Well so far i have the top end off and everything is messed up. Cylinder wall is destroyed, head is all dinged up and piston is wrecked.... It bums me out even to type this, but does anyone have some idea of what could have happened????

Pics are required.

Did you check the ring gap before installing them?

Makes me sick... I cant even say I have learned anything from this!






kips seems to be in working order... havent taken them out yet.. will do tomorrow..

http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf

If this is what your talking about no.

I just followed what the repair manual said.. guess thats not too foolproof.

something came apart

Mr. Wibbens wrote:something came apart

+1

Or maybe one of the circlips came out of the piston. I'm super paranoid about those, I usually check 6 times to make sure they are seated all the way.

What is the red stuff in the last photo?Are you sure the rings where seated against the pin?Could some debris have found its way into the cylinder during the rebuild?just thinking out loud

Check to see if a piece of pin circlip broke off

my vote goes for wristpin circlip.
option B would be one of the ring wasn't installed right...
you need to find out what went wrong...u live u learn

Yep, circlip would be my guess after seeing the pics. I would like to see pics of the piston when you pull the cylinder off.

Yeah, I'd guess circlip or rod bearing.

Looks like either the circlip or a bearing came apart. Those are some mighty sharp and consistent scratches that appear about the right size to be the wrist pin bearing needles. Did you replace that while doing your top end?

well found the culprit... it was the circlip!!!

so I took the jug off (holding the engine on its side incase some metal was still trapped in there) and look at the piston to find no circlip.

So at this point there is probably some metal in the lower end. Do I rip apart the bottom end and search? I rode about 2-3 miles with it in there so Im pretty sure its chewed up... (along with everything else down there)

It shifted through gears no problem..

I am dreading down the bottom end, I dont have any of the specialty tools needed to do this so i would have to buy them all. (and i F*ED the top end I dont want to do the same to the bottom.)

As far as the cylinder am I going to have to sleeve it or is this repairable?

doing the bottom end..*****

live and learn

dgraver wrote:doing the bottom end..*****

Yes indeed that is the right decision. Don't worry about the gears, that's all seperated from the crankcase. Gotta hand it to you for sticking with it and seeing it through, I hope you do as you'll get a lot of enjoyment out of the bike when it's fixed.
Curious if you installed the clips with the opening at 12 or 6 like you're supposed to? Any idea why it came out? It does happen.
Like Wibby said, live and learn.
Good luck.

Yeah. Tearing it down is the best bet if you want to have confidence in the rebuild. Specialty tools are good to have, but honestly, with a little creativity you can complete the task with nothing more than regular shop tools and a flywheel puller. Case splitter is easily made, and coming up with a flywheel clutch/holder is not difficult either. You can certainly get by without a press as long as you own an oven and a freezer. I like to go ahead and pull the flywheel and clutch before removing the cylinder, but you've allready gone that far, it seems.

Go to http://www.rockymountainatvmc.com and watch the case splitting videos. Get the tusk case splitter. Go ahead and get the tusk crank installation tool and have at it. It's really not that bad. Not nearly as bad as sending the cylinder back to Langcourt.... Ouch.