Now What?

[midlifecrisis]

Finally got the bike back together 2 weekends ago.

 

Went out to ride the first weekend, and started her up, but much to my dismay, we found that there was a major oil leak from the countershaft seal, which was fixed, thankfully before any damage occured. I wanted to thank the members of the forum who helped me with that.

 

Went out to ride last weekend, and although it started out running on both, now it runs only on 1 cylinder. I went for a short ride down the road before we went into the pits, and it sputtered and then hesitated mid ride, and then it seemed to kinda die out on one cylinder. I wasnt going hard on the gas, as I was trying to break it in as per the manual. I took it to a local bike shop to have the thing looked at ( ie carbs out of sync, leak down test etc......) and they have told me that it is running 25 lbs of compression on the choke side and 145 on the kicker side? This is a brand new motor. I have been building it for a while (I wont say how long, as I dont want any grief) . I mean I havent got 5 minutes on the engine?

 

My mods are Vitos crank, vitos rods, wiseco 64.50 mm pistons, ported cylinders, vitos hemi head, procircuit pipes.

 

I know low compression is a bad thing obviously, I know I will be removing the cases again to look for any signs of shrapnel, but any help on posible causes would be great, I just want to ride!

Edited May 22, 2010 by midlifecrisis

[#1JUANstunna]

Did you or the shop do a leak down to make sure you don't have any leaks? Leaking head gasket on that side? Bad bore? Forgot to put the rings on that piston? I don't know your mechanical ability so I'm not trying to be a dick.

[midlifecrisis]

Actually, I took it apart tonite, and found some pretty serious damage on my left piston. Almost like something was bouncing around, then I noticed a small dome sticking vertically out of the piston. It is a small dome like 3 mil diameter 5 mil long and it looks like steel, versus aluminum, its almost like a nerd candy in steel.

 

Anyone have any idea where this might have come from?

[firebanshee]

Actually, I took it apart tonite, and found some pretty serious damage on my left piston. Almost like something was bouncing around, then I noticed a small dome sticking vertically out of the piston. It is a small dome like 3 mil diameter 5 mil long and it looks like steel, versus aluminum, its almost like a nerd candy in steel.

 

Anyone have any idea where this might have come from?

Sounds like the pin in the piston that locks your piston rings in place.The pin were the ring gap goes.

[#1JUANstunna]

I agree with firebanshee. It sounds like you are talking about the piston ring locators that hold the ring gaps in a set place so they don't get turned over top of the other and loss compression. Can you post up a pic? Was it on the intake side or exhaust? There should be two pins one in each piston ring groove.

[midlifecrisis]

Youre kidding! I thought it was something that had somehow come loose from the carbs and got sucked in!

 

I remember looking for the locators on the pistons when I located the rings, but I had no idea that they were an item that would move? They can come loose like that? I will post pics tomorrow.

[midlifecrisis]

Here are the photos of the piston and head. I found the ring locator pins that you guys were talking about, but this culprit is way bigger, as you can see it is still stuck in the top of the piston in front of my finger.

 

http://s752.photobucket.com/albums/xx162/amidlifecrisis/Bashed%20piston/

[fck55mph]

wow! thats ugly...even the right cylinder piston looks scarred up on the skirt. hard to tell what that piece is.

[midlifecrisis]

So whats causing the wear on the skirt? Its only been in the bike for 5-10 minutes? I ran it at 20:1 (blue marble premix, w 93 octane, 20 cc domes) for the first 5 minutes as a break in mixture, I didnt get the cylinders honed out when I bought them, but the pistons came with them as a set, and they were visually perfect.? I tell you though that the issues are starting to take their toll. I know theyre my fault one way or another, but enoughs enough.

 

I just wanna ride it

[camatv]

looks like a round part of a needle bearing either the top end bearing or the lower end bearing OR something fell into the motor and caused it. pull the piston on that side and check the needle bearings really closely see if the piece is in the pipe

[midlifecrisis]

OK, so I pulled my pistons out, and all of the needle bearings are intact on both sides, so I called the distributor here in Canada for Vitos and he told me that the bearings on the crank for the rods are 4.5mm, so the one thats stuck in the top of that piston, (if thats what it is), is only 3mm (the same size as the needle bearings for the piston end). So I checked the bearings that came out of the previous cylinders before I switched to this set, and all of those bearings are there as well. So now Im really stuck as to where it might have come from? Anyone else got some ideas?

 

The previous pistons also seem to have a much tighter fitting ring as well?

 

Also, what could be causing the premature wear on the pistons?

 

Im assuming that even tnhough the cylinder sleeve looks and feels fine, that I should have them honed out before I proceed?

 

Thanks in advance for any help!