Check out my "bad bore"

[ctbale]

First off, I cant even believe I put this thing together, it was like this after I got the cyl back from the "machinist" Its got about 60 to 90 mins on the new piston/bore, it sounded like crap and after 3 oil changes there was still gobs of metal in the oil. I am boned on the cyl, I went to 3rd over and I dont think .010 will clean it out for a 4th over piston, I am so pissed!!!!!!!!!!!!!! I had a new vesrah rod kit put in by the same guy, I even printed the manual showing that any tooth needs to be lined up with the woodruf slot, it was not even close! Did I mention I am sooo Pissed!!!!!!!!!!!!!!!!!!

I have a worn regular 200 cyl on standard, less fins, but I am in Alaska.

check out this video, I noticed that I got the piston 180 degree off, should not matter for the vid, it was in correct when installed.

http://www.youtube.com/watch?v=2Ws7RwHU2lk

[ctbale]

Here are more pics

[WilliamJ]

Hard to tell looking at the photos but doesn't look like 5 thou of damage in the bore. It may be usable.

Are you saying the rod has been fitted wrong and caused it? Are the clearances wrong? Were the rings badly fitted / wrong size?

You need a different machine shop to measure and inspect it properly to see if the cylinder is usable.
Bill

[shortline10]

Is that slop in the piston with the rings installed in your video ? What is the ring gap measuring at ?

[ctbale]

thats just the piston in the cyl, no rings, i will make a vid with it with all 5 rings install too. end gap of the two compression rings using the piston to square them up is at .013' to .014' thru the entire stroke, not great but not bad? My compression was 170 to 175. The problem is a LOUD scraping sound when its running, I have swapped out cams, no help. Today with the cyl off I looped the cam chain around my thumb and by holding the top of the rod spun the crank very fast, got oil up the oil port, and everything was silent and smooth as silk. Wrist pin looks good too. Its a shindy piston, at the skirt front to back in the bore, its pretty tight. Measuring the piston, the diff from front to back and left to right is .016" at the skirt. and my wisco is only .009" Forged vs cast? I have a fair amount of experience with honda and yamaha engines and this has me stumped. How does that cyl look to you guys for aprox 90mins of run time?

[shortline10]

Compression is good and the ring gap is acceptable and I see no blow by on the piston but the bright spots/scrapes in your cylinder say to me the piston is egg shaped and possibly no good , that would be my guess . How does the crank look when you rotate it ? does it spin true and straight ?

[ctbale]

when the vesrah rod kit was installed, when I got it back, one of the installed thrust washers was bent, like a potato chip. there was a gap, but you could see the washer had a wave in it. The rod had resistance to rotation, the guy said it came like that and tried to straighten it. I would have just re-used one of the old ones. Could that resistance be pushing the piston forward against the cyl wall? Its loosened up after running it, but the rod dont flop around like they usually do!

[Dirtcrasher]

Your machinist suks...............

[shortline10]

Sounds like he didn't get the rod pin right the first time and had to press it out and start over which will bend the fragile washers, the bearing might be compromised as well .



when the vesrah rod kit was installed, when I got it back, one of the installed thrust washers was bent, like a potato chip. there was a gap, but you could see the washer had a wave in it. The rod had resistance to rotation, the guy said it came like that and tried to straighten it. I would have just re-used one of the old ones. Could that resistance be pushing the piston forward against the cyl wall? Its loosened up after running it, but the rod dont flop around like they usually do!

[ctbale]

come-on DC!!, you more experienced guys are supposed to tell me something I dont already know! LOL

Getting burnt out on my 200x, I think I will go putt around on my 70 or my 90 and come up with a plan, my dog likes those bikes better anyway.

[ctbale]

On a new rod, with a good intallation, will there be slight resistance like on a new sealed wheel bearing, or will it "flop" from its own weight? Just checked the side to side, there is .008" gap

[ctbale]

Thinking hard about 10.25:1 wiseco, next size up.

[shortline10]

Should spin freely with no resistance if done correcty .




On a new rod, with a good intallation, will there be slight resistance like on a new sealed wheel bearing, or will it "flop" from its own weight? Just checked the side to side, there is .008" gap

[Dirtcrasher]

^ Exactly, it's a needle bearing with some side to side clearance. No resistance or play should be felt............

[ctbale]

S#!T!! Now its a "due over" on the crank and the piston/cyl !!

[zzmegad]

you gotta find a guy who does cranks all day and has all the right jigs and fixtures, same goes for your boring, an ordinary machinist is most likely not properly setup, especially for $50 bucks or whatever the going rate is for a crank rebuild or bore job

[ctbale]

This guy even said he repairs cam journals, he just needed the cam to set the clearance, that seemed like he was pretty sophisticated as far as a machinist goes.

[Dirtcrasher]

^ Would you rather it blew up?

Take care of that timing chain and both guides too while your in there............

[ctbale]

Thats why I am pissed, I just did a total overhaul, vesrah con rod on the crank, piston, rings, bore, new vesrah valves, timing chain, guides, stiffer kickstarter spring, 2 new tranny bearings, everything I did was golden ...

[just ben]

.014 clearance? should be .005 looks like they went .040 over with a .030 piston. lucky the piston didnt grenade and take out the rod/crank. the resistance in the rod bearing is probably the aluminum that you show in the oil binding in the bearing. good luck to you. On a side note, did alaska get a big heat wave last week?

[ctbale]

yup! was a hot 72!! Fairbanks gets a few 90s every year believe it or not. But they also get several months of 20 to 30 below

[JasonB]

sorry to see this man, that really does suck!

[bigworm626]

Sorry to hear, that was a golden overhaul. Shoot.

[ctbale]

yea, little burnt. But I aint going to give up on it!!!! The only thing I regret is the choice of machinest and the Shindy piston. Everything else was top line, heck I even got a Vesrah full gasket kit for the reassembly. Overhaul Round II : Wiseco 6th over 10.25:1