Post by richard on May 7, 2010 14:20:36 GMT -5
So after returning from my business trip I took my bike out for ride to warm it up. When I returned I did a compression test on it and got 100 on both cylinders. The rings just didn’t seem to be reseating like I hoped it would. The timing chain was still noisy and it just seemed like time to do something about it. So I decide now was as good a time as any. The next morning I started removing the engine. Well I started at about noon after running some errands. By 4:30 I had the engine out and set it on on a cart.
Standing there looking at the engine on the cart I decide I’m just too dammed old to rebuild this thing bent over that cart. I have a bench in the garage put like most it's full of stuff. So I decided to make something to hold the engine. I got on the internet and found that Harbor Freight had an engine stand for $39 bucks which seemed reasonable to me, all I needed was a bracket to hold the engine on the stand and I would be set. The next morning I bought the engine stand and a length of 1 1/4 black pipe from Lowes. I have a Hydraulic tubing bender so I laid the engine on its side and bent the pipe to match it. Allowing enough room on the bottom of the bracket so that I could split the case while the engine was mounted if needed to I figured 10 inches should do it. I welded the pipe to some plate I cut and drilled to match the engine stand and once it was welded I shot it with black spray paint. Once it was dry I mounted the bracket to the engine and set it in the stand. Let me tell you that engine was heavy for a single person lift. I wouldn’t do it again. Next time I’ll use a lift to pick it up. The next day I started pulling the engine apart and this is what I found.
Bike with engine removed
Engine Placed on cart for the time being
This is the engine stand with Engine mount I built
This is the engine in the stand before I started taking it apart
One of the #3 screws heads stripped so I had to drill the head off of it and then us an extractor to remover it.
Lifting the rocker off the cylinder head
This is the timing mark at TDC on the Crank. Off center is due to cam chain wear.
This is the cam tensioner in the head between the barrols it is all the way in rubbing on the head between the cylinders as I suspected. I could hear it while riding.
This is the head with the cam removed before lifting it off.
This is the cylinders Before I lifted them off. I thought they looked pretty salvagable and the measured at 75mm with the telescoping guage and caliper. I'm going to re- check the clearance before going any further. The new piston fit was snug but slid in just fine from the bottom. I think I'll just hone the cylinders and use them.
This is the grooving done by the cam chain as the tensioner pushed the chain up against the vane between the heads.
The engine with the head off. I check the slop in the rods and pins briefly and there was no movment that I could tell but I do I better check tomorrow with a dial indicator.
The Valve pockets on #1 they both look like they are burning rich but this one is the worst.
This is number 2 it's not as bad but it is still too rich. I am not sure if the carburetion is wrong or it is just the other factors like low compression or the timing being advance because of cam chain wear.
These are the barrel markings. I'm not sure exactly what they mean other than the oversize? As far as I know these marking indicate that the left cylinder was originally 75.001mm inside diameter and the right was 75.000mm in diameter.
I also wasn't expecting this strange numbers on the piston. this indicate the pistone was originally 74.949 in diameter.
Here is the other with 950 on the crown which indicates 74.950mm in diameter.
This is a pic of the cylinder bore. There are no scratches or ridge at the top to speak of. I think they will clean up just fine so now I have to sets of stock cylinders and it looks like two sets of pistons.
I am going to mic the piston skirts and pins tomorrow but they look ok visually at this point. I may change the pins on the pistons just to be safe but I want to mic them first to see if there is any wear. they may be ok. It's hard to tell at this point.
Well that's it for now. I hope you enjoyed this post
Richard
Standing there looking at the engine on the cart I decide I’m just too dammed old to rebuild this thing bent over that cart. I have a bench in the garage put like most it's full of stuff. So I decided to make something to hold the engine. I got on the internet and found that Harbor Freight had an engine stand for $39 bucks which seemed reasonable to me, all I needed was a bracket to hold the engine on the stand and I would be set. The next morning I bought the engine stand and a length of 1 1/4 black pipe from Lowes. I have a Hydraulic tubing bender so I laid the engine on its side and bent the pipe to match it. Allowing enough room on the bottom of the bracket so that I could split the case while the engine was mounted if needed to I figured 10 inches should do it. I welded the pipe to some plate I cut and drilled to match the engine stand and once it was welded I shot it with black spray paint. Once it was dry I mounted the bracket to the engine and set it in the stand. Let me tell you that engine was heavy for a single person lift. I wouldn’t do it again. Next time I’ll use a lift to pick it up. The next day I started pulling the engine apart and this is what I found.
Bike with engine removed
Engine Placed on cart for the time being
This is the engine stand with Engine mount I built
This is the engine in the stand before I started taking it apart
One of the #3 screws heads stripped so I had to drill the head off of it and then us an extractor to remover it.
Lifting the rocker off the cylinder head
This is the timing mark at TDC on the Crank. Off center is due to cam chain wear.
This is the cam tensioner in the head between the barrols it is all the way in rubbing on the head between the cylinders as I suspected. I could hear it while riding.
This is the head with the cam removed before lifting it off.
This is the cylinders Before I lifted them off. I thought they looked pretty salvagable and the measured at 75mm with the telescoping guage and caliper. I'm going to re- check the clearance before going any further. The new piston fit was snug but slid in just fine from the bottom. I think I'll just hone the cylinders and use them.
This is the grooving done by the cam chain as the tensioner pushed the chain up against the vane between the heads.
The engine with the head off. I check the slop in the rods and pins briefly and there was no movment that I could tell but I do I better check tomorrow with a dial indicator.
The Valve pockets on #1 they both look like they are burning rich but this one is the worst.
This is number 2 it's not as bad but it is still too rich. I am not sure if the carburetion is wrong or it is just the other factors like low compression or the timing being advance because of cam chain wear.
These are the barrel markings. I'm not sure exactly what they mean other than the oversize? As far as I know these marking indicate that the left cylinder was originally 75.001mm inside diameter and the right was 75.000mm in diameter.
I also wasn't expecting this strange numbers on the piston. this indicate the pistone was originally 74.949 in diameter.
Here is the other with 950 on the crown which indicates 74.950mm in diameter.
This is a pic of the cylinder bore. There are no scratches or ridge at the top to speak of. I think they will clean up just fine so now I have to sets of stock cylinders and it looks like two sets of pistons.
I am going to mic the piston skirts and pins tomorrow but they look ok visually at this point. I may change the pins on the pistons just to be safe but I want to mic them first to see if there is any wear. they may be ok. It's hard to tell at this point.
Well that's it for now. I hope you enjoyed this post
Richard