Bandits '77 GS750 Revival

[93Bandit]

Hey guys,

Starting yet another build thread, but this time I'm serious, I promise! My previous build threads were started when I was in the middle of a move, everything in storage, then buying a house so I was trying to be ambitious yet failed. This time it's for real though! We're settled into the new house, I've finished getting my garage set up for the build (cleaned out, heat installed, benches built), and most importantly, my wife said GET THOSE BIKES DONE. Aye Aye, Captain! :dancing:

I don't believe I've posted much about this bike yet, but I bought it Nov 2019 if I recall correctly. Bought it from a truck driver who never had time to ride it so it had been stored in his parents dirt floor barn for years. He rode it occasionally, but said it hadn't ran in about a year at the time I purchased it. I took it home (to a storage unit rather) and it has sat the last two years. Brought it into the garage this evening and I have parts on the bench ready to begin.

I think my overall plan for this bike is simply to revive it. It's not perfect but it's complete (minus a side cover) so I intend on preserving it. Probably won't do a full-on restoration. I kind of like the patina it has and I think it'd look good cleaned up cosmetically with all the mechanicals repaired/rebuilt as necessary. To start, I'll be rebuilding the carbs, new intake boots, air filter, plugs, and anything else it takes to get it running. Then I'll rebuild the brakes, suspension, new tires, and hopefully start riding it. Not sure on overall timeline. I hope to have it road worthy by spring (budget permitting), but it may take more time than that depending on how things go.

Right off the bat, I need to do something about the mismatched rear fender/tail (not sure what it's called) and find some new side covers. I'd like to get some OEM side covers but man they're expensive... Maybe I'll try to make my own out of fiberglass?

Enough rambling, here are some pictures. Let me know what you guys think, and if you have any ideas.







Any thoughts or ideas are appreciated!

 

[Rob S.]

Lose the crash bar!

 

[93Bandit]

Lose the crash bar!

I plan on putting it on my 850.

 

[Grimly]

I plan on putting it on my 850.

It's an ugly fecker of a crash bar, but a great place to mount auxiliary lights.
It will probably do a good job of protecting the cases, though.
Ignore the anti-bars peanut gallery. They've never had to walk home because of a punctured engine casing.

 

[Rob S.]

They've never had to walk home because of a punctured engine casing.

I ride in an ambulance. :-\\\

 

[93Bandit]

It's an ugly fecker of a crash bar, but a great place to mount auxiliary lights.
It will probably do a good job of protecting the cases, though.
Ignore the anti-bars peanut gallery. They've never had to walk home because of a punctured engine casing.

You read my mind. I'm considering some fog lamps on the crash bar once installed on the 850.

 

[Grimly]

I ride in an ambulance. :-\\\

Well, if you're going to do it, do it right.

 

[93Bandit]

Made a little progress Friday night. Pulled the carbs and disassembled them on the bench. Overall they don't look too bad inside. I've seen much worse, so maybe a few hours in dip and a thorough scrub and they should be ready for new o-rings. The new intakes arrived yesterday. I plan to start cleaning this evening and get them on the bike early next week. Wife and kid will be out of town so I'll have more shop time to get things done. Frame and engine need a good scrub as well so I will likely do that before putting it back together.


Oh, I left the crash bar on just for you, Rob! :biggrin:

 

[93Bandit]

Made quite a bit of progress yesterday. Got the carbs all cleaned up and reassembled with new orings. Put them back on the bike with new OEM suzuki intakes. Scrubbed some of the grease and dirt off the frame and engine and airbox and put it all back together. I pulled points cover off thinking I'd need to clean them, but they look brand new. PO must have put new points and condenser on it at some point. I decided to trust their installation and put the cover back on. Filled the tank with some fresh fuel, set to PRIME and would you know, it fired right up on the first crank. I couldn't believe it.

Here's a picture of the "cleaned" engine... I only cleaned the worst of the grime off. I'll do a thorough scrub once the engine comes out for a rebuild someday.



Also, a video of the first start. You'll see my surprised face after it fires. (Click on image)




I ran it for a bit yesterday and it has a hanging idle and doesn't want to idle so I think the carbs need fine tuning of the idle jets and a balance.

 

[Rob S.]

Wow! Imagine how good it would run without the crash bar.

 

[93Bandit]

Wow! Imagine how good it would run without the crash bar.

We may never know! hahaha

I'll take it off sooner or later.

 

[Rob S.]

image by Bob Wayne

Notice on my first bike (which was a genuine pussy magnet) crash bars, complete with highway pegs. After about a year, I thought, "What do I need these for?" Off they came. Off came the padded sissy bar/luggage rack. One benefit of no backrest is, the kitties have to wrap their arms around you. Of course the stubborn creature in the pic always insisted on sitting in front.

 

[slayer61]

Made quite a bit of progress yesterday. Got the carbs snip for brevity Also, a video of the first start. You'll see my surprised face after it fires. (Click on image)




I ran it for a bit yesterday and it has a hanging idle and doesn't want to idle so I think the carbs need fine tuning of the idle jets and a balance.

I was trying to explain to my (younger than me) wife the odd phenomenon of the '80s where tank badge emblems were swapped & inverted for "show". I'm glad to see you're continuing the fad into the current era. Well done Sir!

 

[Rich82GS750TZ]

I was trying to explain to my (younger than me) wife the odd phenomenon of the '80s where tank badge emblems were swapped & inverted for "show". I'm glad to see you're continuing the fad into the current era. Well done Sir!

Yeah, he's so retro, he even flipped the petcock to the right side of the pike, and also inverted the logos on his Craftsman Creeper and his Stihl leaf blower.

 

[93Bandit]

Yeah, he's so retro, he even flipped the petcock to the right side of the pike, and also inverted the logos on his Craftsman Creeper and his Stihl leaf blower.

LOL It took a lot of effort to do all that, but when there's a will there's a way

 

[93Bandit]

So I went out to the garage on my lunch break. Tried to start the bike but it would not start, wouldn't even cough. Just endless cranking. Checked fuel, checked spark, all good. Checked petcock, all good. Hmmm...

After cranking for a very long time, it started barely running on full choke but only if I continued engaging the started. It would run with starter on, but not once I let off the starter. Then I cranked it again, heard a loud metallic POP and it roared to life and idled at around 1500. Then another pop and idle surged to 3k. Then the top end really started clattering (and I'm not talking about cam walk), sounded like cards in your bicycle spokes. So I shut it off and went inside.

I haven't adjusted the valves yet but it fired with zero effort yesterday and ran well. What happened over night? I'll be pulling the cam cover today or tomorrow to start investigating.

Maybe the cam timing somehow got off? The popping noises I heard scare me...

Any ideas are appreciated.

 

[93Bandit]

I re-watched the first start video I posted. If you go to the 30 sec mark, you can hear the metallic pop/tick I mentioned in my previous post. I jump a little as it happens. I didn't think much of it at the time, but that's the same exact sound it made today when the idle surged.

 

[93Bandit]

Pulled the cam cover and inspected the cams and timing chain. Didn't see any signs of damage, the chain was tight.

Measured valve shim clearances and below were my results. Service Manual says I: 0.02-0.05mm, E: 0.03-0.06mm

Cylinder 1:
I: 0mm clearance, 2.7mm shim
E: 0.076mm+ clearance, 2.7mm shim

Cylinder 2:
I: 0.038mm clearance, did not measure shim
E: 0mm clearance, 2.7mm shim

Cylinder 3:
I: 0.051mm, did not measure shim
E: 0mm clearance, 2.7mm shim

Cylinder 4:
I: 0mm clearance, 2.8mm shim
E: 0mm clearance, 2.7mm shim

So 5 valves are tight, C1E has substantial clearance, more than spec, and C2 & C3 intakes are in spec. Could this really have caused my starting issue today? Since I didn't see anything else going on I'm going to order some shims and see if that fixes it...

Also peaked inside each cylinder with my bore scope and didn't see any issues. No PTV contact marks that I could see. Can still see good crosshatching on the cylinder walls.

 

[Grimly]

Those numbers would normally lead to hard starting, yes.
The reason it started yesterday was probably the presence of sufficient fuel vapour through some splashing around over the previous while and sittiing in the inlet tracts.

 

[93Bandit]

Those numbers would normally lead to hard starting, yes.
The reason it started yesterday was probably the presence of sufficient fuel vapour through some splashing around over the previous while and sittiing in the inlet tracts.

Appreciate the input.

I've got 8 thinner shims leftover from the last time I shimmed my 850 so I might just have what I need to re-shim without having to order any. I do need a new cam cover gasket though. I'll have to order that but that's not a big deal. I'll shim the valves and see if it starts/runs any better. Probably won't happen until after the 1st of the year. Stand by...