New Project '81SH

[Prothec]

I picked up this '81SH from Craigslist at the beginning of the year in January and am finally getting to work on it. Since then, I have also picked up a titled '79SF with fire damage that came paired with a reasonably complete '79F parts bike. I'm not sure yet what my plans are for the '79SF...

This '81SH has ~95k miles on it and may have been parked for a couple of seasons outside.

So far I have:

• Changed oil
• Checked compression
• Cleaned carbs - replaced diaphragms with JBM Industries diaphragms
• Replaced pickup coils (1 bad pickup coil, other had 2 broken wires)
• Replaced fuse block (used my spare, new spare has been ordered from TC!)
• Checked valve clearances (adjusted a couple, still need some shims)

After cleaning the carbs, I found I didn't have spark. I found one pickup coil was testing 4 MOhm, the other tested open, so swapped in another good set of pickup coils.

At this point I have fired up the bike to a pretty loud clatter in the top end. On the bright side, this exhaust sounds really good otherwise! I pulled the valve cover and there is evidence that the cam chain has hit the underside of the valve cover. The tensioner had maybe 1 mm of movement left. Unfortunately, I didn't pull the tensioner before adjusting it so I have no idea if it picked up any slack.

Because the tensioner plunger did have a tiny bit of adjustment left, I think I will go ahead with buttoning it up and starting it again and try to get a better idea where the noise is coming from, if it still exists. I haven't ruled out an exhaust leak yet. I definitely need to replace the cam chain and add an ACCT.

Basically, I have a bike with 95k miles and an unknown history. I'm excited to see this start to come together as it is surprisingly in pretty good cosmetic condition.

[BowlingSS]

That is a lot of miles. What was your compression? I would replace the cam tensioner. I had a very bad noise in the engine until I installed an auto adjuster.

Good luck.
Bill

[Prothec]

Before adding oil to the cylinders, 1, 2 and 4 were around 140 and 3 was around 130, IIRC.

Most of the valve clearances are a size or two too tight as well.

Before I dig too deep into the engine, I'd like to assess what I can. Ideally, I'll get an idea what shape the transmission is in, etc and determine if I should just pull the engine.

It's clear the cam chain needs replacement and certainly going the ACCT route like I did with my XJ and '78 engine rebuild that has lived on an engine stand for probably well over a year now. My '78 project might get resurrected this winter.

This '81SH project is a lot closer to being on the road than the '79SF I have. The '79SF will basically need to be turned into a '79F with the parts I have. Someone put 3" or so shorter shocks on it and a bunch of ugly "custom" parts along with drilled out locks, burned and completely destroyed wiring harness and a quite a few missing/presumably destroyed parts. Supposedly the '79F parts bike that came with it only has 6k on it, if you believe the seller and the odometer. It also came with a box of new parts still in their packaging. with a brand new set of white letter Bridgestones that are going on my XJ before long.

[TopCatGr58]

Hey Prothec,

Not sure if I would want to trust the OEM CCT. You've got good compression levels even with TIGHT valve clearances. You don't want the tensioner to slip and allow the worn loose change to slip teeth, go out of cam timing and bend some valves! THey are getting harder to find as well as $$.

Folks have reported getting 200K out of their engines...so with a hopefully mostly highway set of miles...bike looks rigged for LDRs, then the mileage isn't so bad compared to the same miles but from in town riding!

Would be nice to know WHY it was parked...due to ignition problems, or tranny problems. A little hard to check/test the tranny when it's not running.

T.C.

[Prothec]

I'm willing to bet it was parked over the ignition problems. After rebuilding the carbs, I tried to fire it up and wasn't getting spark from either coil. The pickup coils didn't look like they had ever been touched. After the coil swap, it fired up immediately.

With your advice, I'll at least swap in the ACCT from my '78 engine before I try to fire it up again for a little piece of mind.

Here's the bike on the lift with the carbs temporarily installed. Yes, the airbox will ultimately be reinstalled.

[Prothec]

I swapped in an ACCT and fired back up and verified the top end noise is gone. I'm happy with the condition of the engine so far. I ordered a cam chain and brake rebuild kits, so I've started disassembling and cleaning the calipers and master cylinders while waiting for parts.

There's a ~6 mm hole drilled on each side of the grab rail about 4 inches back from the top shock mounts. Any guesses what these might have been used for? I noticed them after removing the luggage rack.

[jwhughes3]

They might have used the holes for bungee hooks.

John

[BowlingSS]

Nice project.

Bill

[motoman]

I picked up this '81SH from Craigslist at the beginning of the year in January and am finally getting to work on it. Since then, I have also picked up a titled '79SF with fire damage that came paired with a reasonably complete '79F parts bike. I'm not sure yet what my plans are for the '79SF...

This '81SH has ~95k miles on it and may have been parked for a couple of seasons outside.

So far I have:

• Changed oil
• Checked compression
• Cleaned carbs - replaced diaphragms with JBM Industries diaphragms
• Replaced pickup coils (1 bad pickup coil, other had 2 broken wires)
• Replaced fuse block (used my spare, new spare has been ordered from TC!)
• Checked valve clearances (adjusted a couple, still need some shims)

After cleaning the carbs, I found I didn't have spark. I found one pickup coil was testing 4 MOhm, the other tested open, so swapped in another good set of pickup coils.

At this point I have fired up the bike to a pretty loud clatter in the top end. On the bright side, this exhaust sounds really good otherwise! I pulled the valve cover and there is evidence that the cam chain has hit the underside of the valve cover. The tensioner had maybe 1 mm of movement left. Unfortunately, I didn't pull the tensioner before adjusting it so I have no idea if it picked up any slack.

Because the tensioner plunger did have a tiny bit of adjustment left, I think I will go ahead with buttoning it up and starting it again and try to get a better idea where the noise is coming from, if it still exists. I haven't ruled out an exhaust leak yet. I definitely need to replace the cam chain and add an ACCT.

Basically, I have a bike with 95k miles and an unknown history. I'm excited to see this start to come together as it is surprisingly in pretty good cosmetic condition.

First: follow instruction on THIS forum and get rid of stock tensioner for an auto tensioner from a v-4 Venturer, 84 an later! Lots more to do but thats a starter for ya!

[Prothec]

I finished removing the exhaust and found this rusted out/badly broken weld at the crossover pipe. Any suggestions for finding someone who might be able to repair it?

I figure I'm going to need to work on getting the crossover pipe and header separated, baffle removed and clean up the area before I take it anywhere.

Or is it time to look for a replacement muffler?

[motoman]

I finished removing the exhaust and found this rusted out/badly broken weld at the crossover pipe. Any suggestions for finding someone who might be able to repair it?

I figure I'm going to need to work on getting the crossover pipe and header separated, baffle removed and clean up the area before I take it anywhere.

Or is it time to look for a replacement muffler?

Easy fix for me with my TIG welder......then a shot of high temp silver.......it'll stay fine foreve.

[Prothec]

Easy fix for me with my TIG welder......then a shot of high temp silver.......it'll stay fine foreve.

I was relatively sure from what I've read that it's fixable. Hopefully after I get this fixed up, I'll be able to say I know a guy who knows a guy.

[Prothec]

This weekend, I found some time to clean up and paint the calipers and master cylinder, disassemble the exhaust and replace the cam chain.

This is the first cam chain I've replaced on one of these bikes with the engine in the frame. I spend a decent amount of time trying to fish the cam chain back around the crank sprocket. After spending a decent part of a day fighting with it, I eventually found a piece of copper wire (4 AWG? - ~5mm diameter) and pounded the end flat so I could reach it down the tunnel from above the frame and help guide the chain over. It took maybe 10 minutes to guide the chain over. Maybe it was dumb luck, but this actually seemed to work pretty well.




And.. here are some of the painted parts.





I still need to try to find someone to weld up the mufflers, but I did get around to tearing them down.

[Prothec]

I've done little odds and ends for a while on this project and am ready to get back to it and make some progress. The calipers, were leaking past the seals after the rebuild for some reason. I pulled them apart yesterday and made sure the seals weren't damaged and hit them with a scotch bright pad. They're back together and so far so good.

I took the bike around the block today and the transmission feels solid through all the gears despite the >95k on the odometer. I'm getting some smoking out one side of the exhaust and the #3 carb tends to overflow, but it's firing on all cylinders and feels good.

The starter isn't always grabbing well.. With everything else seemingly working well, it's time to work towards finishing the project and making it a daily rider.

[Prothec]

No more smoking exhaust and everything is now running well. I'm ready to start buttoning everything up and take it for a shakedown ride, maybe this weekend.

• Overflowing carb - found that the float was catching on the bowl. I bent the stop on a couple of the floats to keep them from catching.
• Erratic and runaway idle, then some backfiring - Re-adjusted the valves, stripped and cleaned carbs again, found another break in a pickup coil wire and re-synced carbs
• Lots of cleaning and polishing
• Cleaned all electrical connections and ground
• Re-soldered connections in left handlebar controls
• Added brackets to Dyna coils for better clearance
• Re-built forks
• Cluster gasket replacement
• New seat cover

Lots of cosmetic stuff left. I'm in the process of re-finishing the tank and side cover emblems.