ADVrider

Go Back   ADVrider > Bikes > Old's Cool > 2 smokers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 02-05-2012, 12:07 PM   #1
LotaBikes OP
Adventurer
 
Joined: Aug 2010
Location: La Verne CA
Oddometer: 79
1965 YJ2 Low compression (60 cc)

Hello,
Maybe someone can help with a few questions I have. I have a 1965 YJ2 that I am restoring. Everything is basically done except getting the tank re-chromed. I am having some mechanical issues however.The issue is that the bike will start and idle and will rev with no load in neutral. It has no mid-range or high end power though when I go to ride it. Bogs out and dies. So far I have cleaned the carb (multiple times) and adjusted the floats. I have replaced both crank seals, the head and base gaskets. I have done a leak down test and it lost maybe 1/2 psi over 6 mins. The biggest issue seems to be compression. The compression test shows only 40 psi. I didn't think it would even run with it that low.The bike only has 1100 miles on it. I would'nt think the compression would be so low. Do I have to rebore and go to the next size piston or will new rings do the trick? How do I tell? If I do have to get a new piston and rings, what do I tell the machinist the clearance should be? Or should he already know? Any help would be appreciated.
LotaBikes is offline   Reply With Quote
Old 02-10-2012, 09:06 PM   #2
anonny
What could go wrong?
 
anonny's Avatar
 
Joined: Mar 2007
Location: Beautiful Revelstoke BC
Oddometer: 5,374
I'd pull the cylinders and the pistons then remove the rings, after that put the rings in their respective cylinders and push them in square with the pistons and measure the ring end gap for starters.

Plus you will see what shape the piston/ cylinders are in as well as seeing if the rings are stuck in the piston grooves.
__________________
Kawasaki H1 build thread

71- 450 Honda CL re & re

Just another pathetic sheep following the herd

anonny is online now   Reply With Quote
Old 02-12-2012, 04:15 PM   #3
LotaBikes OP
Adventurer
 
Joined: Aug 2010
Location: La Verne CA
Oddometer: 79
Despite the lack of interest in my thread, I did resolve the problem. I did remove the piston and measured my wall clearance at .002. Ordered new standard size rings from ebay, checked end gap which was within spec for both, gave the cylinder a light hone and reassembled. Also adjusted the air screw on carb after 20th cleaning. Bike starts and runs good now. Now that it is going good, I found I have leaking seals on the oil pump that I will need to replace. Fortunately they are still available and cheap.
LotaBikes is offline   Reply With Quote
Old 02-13-2012, 07:19 PM   #4
anonny
What could go wrong?
 
anonny's Avatar
 
Joined: Mar 2007
Location: Beautiful Revelstoke BC
Oddometer: 5,374
Good stuff, whats the compression now?
__________________
Kawasaki H1 build thread

71- 450 Honda CL re & re

Just another pathetic sheep following the herd

anonny is online now   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 09:29 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014