1980 Special Engine Rebuild HELP

[katrina2599]

Good morning!
I'm a new member to the forum and have used this site quite a bit already to get where I'm at in the build.
A little about me: I'm 23 and recently found my dad's 1980 sx650 special sitting around in my uncle's garage. He bought this bike when he was 23 but sold it 6 years later when my older sister was born for some extra cash. I decided to buy it back from my uncle and haul it home to fix up.

A little about the bike: Overall, the body is in good shape with some surface rust. The tank is pretty rusted on the inside with a big dent on the right side (looks like someone laid the bike down as there is a dent on the right exhaust too). Sparkplugs are new but someone got a cap stuck. Battery is dead. Clutch has a lot of free play in the handle. Does not crank.
I have decided the first step is to do an engine rebuild to get this thing running

Steps taken already:
Removed crankshaft cover and it looks to be in good shape
Removed exhausts, seat, tank, carbs
Removed side covers on engine and peaked inside.
Left cylinder looks okay, right seems to be the issue
Pulled the engine and took the top off.

First big issue: cam chain is stuck and will not spin. Is there another way to remove this if I can't spin it to find the master link?


Thanks for any help!

 

[jetmechmarty]

Hi Katrina, welcome aboard.

So, you’re saying the cylinder head cover is off and the engine is seized? Is that why you removed the engine? The pistons are stuck in the bores? You’re not likely to find a master link on the OE chain. You should replace it anyway.

 

[katrina2599]

Hi Katrina, welcome aboard.

So, you’re saying the cylinder head cover is off and the engine is seized? Is that why you removed the engine? The pistons are stuck in the bores? You’re not likely to find a master link on the OE chain. You should replace it anyway.

The engine was seized so I removed it to get a better look at the cylinders. After taking the top off, I was trying to move the chain but it won't budge. Is there an easy way to remove it?

 

[Jan_P]

Is it time for a ladies section ??
If the top is off ..you can se the cam ..and the camshaft bearings
If i recall right it is then possible to either slacken the cam chain adjuster or pull off the cam chain bearings and slacken it taking it ( Chain ) off the sprocket and then move it
Pictures helps.

 

[katrina2599]

Is it time for a ladies section ??
If the top is off ..you can se the cam ..and the camshaft bearings
If i recall right it is then possible to either slacken the cam chain adjuster or pull off the cam chain bearings and slacken it taking it ( Chain ) off the sprocket and then move it
Pictures helps.

We do need a ladies section! And thank you! I will try this

 

[5twins]

Yes, slide the bearings off the ends of the cam and then pull it out from under the chain. No need to break the chain now, it can stay connected until you are ready to replace it. But yes, there is a factory riveted master link on the chain somewhere. It's pretty easy to spot as the factory did a pretty crude job on the riveting, lol .....

When it does come time to break it and remove it, the easiest way is to grind the riveted heads off the link then just tap it out .....

Oh, and welcome.

 

[Adamc]

Welcome Katrina. We are a bunch of enthusiast willing to offer advise and help as needed. The troop here have certainly helped me over the past year and continue to do so. Plenty of pictures tell us more about your bike and it’s issues. Just ask whatever and one of us will reply.

 

[motormike]

I use a wooden dowel to hammer the cam bearings off... keeping them in order. Then the cam can be worked under the chain and out. Marvel Mystery oil in the cylinders for a few days.. then a hard block of wood on top of the piston and a heavy hammer... no hard blows... the weight of the hammer should get the pistons to move. Only had one that the hard wood wouldn't move the pistons. Had to use a air hammer ! I wanted the stock cylinders (Xs1) because my bike had 750 pistons factory installed and I wanted it back to stock.

 

[katrina2599]

I use a wooden dowel to hammer the cam bearings off... keeping them in order. Then the cam can be worked under the chain and out. Marvel Mystery oil in the cylinders for a few days.. then a hard block of wood on top of the piston and a heavy hammer... no hard blows... the weight of the hammer should get the pistons to move. Only had one that the hard wood wouldn't move the pistons. Had to use a air hammer ! I wanted the stock cylinders (Xs1) because my bike had 750 pistons factory installed and I wanted it back to stock.

That'll be really helpful! Thank you!

 

[Wingedwheel]

Welcome Katrina and tapping the bearings off the ends works great just always tap on the inner race not the outer, keep them in order and like Jan said, make sure you take the slack out of the cam chain adjuster first.

 

[5twins]

Well no, you want to put the slack into the chain and adjuster. Actually, you can just pull the adjuster screw, spring, and plunger right out of the back of the cylinder. Nothing will come apart or fall down inside the motor .....

Your 1980 should have a type E adjuster so you'll be looking to remove all the numbered parts below (14 - 17 and 22 - 25) .....

 

[Wingedwheel]

You’re right I said that backwards I meant take the adjuster out. Sorry for any confusion.

 

[katrina2599]

I removed the cam guide and the next level of the engine. One piston looks good, the other wss beginning to weld itself to the cylinder. I was able to beat the pistons down to their lowest position. I'm trying to take off the cylinders but it is fused to side with the good piston. Is there anything I can do to make this easier?

 

[katrina2599]

I removed the cam guide and the next level of the engine. One piston looks good, the other wss beginning to weld itself to the cylinder. I was able to beat the pistons down to their lowest position. I'm trying to take off the cylinders but it is fused to side with the good piston. Is there anything I can do to make this easier?

 

[nj1639]

Mebbe more penetrating oil in that cylinder...... I might be inclined to put a breaker bar on the nut that holds the charging rotor on and play that back and forth. See if that lifts the cylinder with the piston....careful.
Make sure that little 10mm headed bolt at the center rear of the cylinders is out.

I'll add that if you can get to the wrist pins on the bottom of the pistons you can slide them out and remove the cylinder, move it to where you can drive the piston out......

 

[5twins]

You have to take that fitting off the front where the oil pipe was connected to. It blocks lifting the cylinders off. I see it's still on there in your pic.

 

[katrina2599]

You have to take that fitting off the front where the oil pipe was connected to. It blocks lifting the cylinders off. I see it's still on there in your pic.

It looks like it'll clear it. Is there a suction it's holding that'll stop it from freeing up?

 

[willis]

5twins is right. That fitting needs to come out to remove the cylinders.

 

[5twins]

Yes, there's a thin lip along the bottom of the cylinder that fits under the hex on that fitting. It needs to come off. Then it's just a matter of breaking the cylinder free from the base gasket. I hit upwards on it all around it with a rubber mallet.

 

[katrina2599]

Mebbe more penetrating oil in that cylinder...... I might be inclined to put a breaker bar on the nut that holds the charging rotor on and play that back and forth. See if that lifts the cylinder with the piston....careful.
Make sure that little 10mm headed bolt at the center rear of the cylinders is out.

I'll add that if you can get to the wrist pins on the bottom of the pistons you can slide them out and remove the cylinder, move it to where you can drive the piston out......

This worked great with the charging rotor! Popped the cylinder right off!