1978 gs 750e cafe racer rebuild

[drivera84]

Ive been posting for a while but I decided I would start my rebuild tread. I own a 1978 gs 750E which is in very poor condition.

Ive already ordered a 1980 gs750 engine with good compression numbers to replace the existing one...at least till I get up the money to fix this one up. Ive also ordered the complete rebuild kit for the brakes and the clubman bars.

My plans for the rebuild are to use the rear cowl and tail light assembly and just slide it a little forward (cut the frame just a bit). Fit the clubman bars and make a custom seat pan and seat. I was thinking about this idea when I found beergood (a member here) rebuild. He did almost exactly what I have in mind. the exhaust is missing I only have the headers so I plan to buld a 4-2 custom pipe while I look for a kerker or v&h 4-1 megaphone.

Im waiting on the parts to begin building but since I am in honduras its going to take a while.


this is her current sad state...please feel free to give me your opinions. If you have parts you think I might need please feel free to let me know. Im on a tight budget but need parts.

 

[Guest]

I'm gonna tag along for this one, should be pretty cool

I assume you've seen Beergood's cafe build?

 

[drivera84]

Hi Pete,

In fact Ive seen most if not all the rebuild posts! Ive enjoyed plenty of reading. Ive also sen cosatiepete?s build.

At first I wanted to do somthing of a bobber but slowly my mental picture of what the bike was going to look like started changing to a cafe style bike. I decided I wanted to keep the original look so thats why Im keeping the rear cowl, very much like beergood.

 

[Guest]

Hi Pete,

In fact Ive seen most if not all the rebuild posts! Ive enjoyed plenty of reading. Ive also sen cosatiepete?s build.

At first I wanted to do somthing of a bobber but slowly my mental picture of what the bike was going to look like started changing to a cafe style bike. I decided I wanted to keep the original look so thats why Im keeping the rear cowl, very much like beergood.

Good stuff. Coastiepete's is one of my all time favourites on here, but Beergood's came to mind because of the tail piece comment...

 

[drivera84]

Just got my brake parts in! Cant wait too get home and take a look!

thanks cal_look_zero!

 

[drivera84]

 

[Etcheberri]

cool,
have fun with your rebuild!

 

[drivera84]

thanks etcheberri,

im already having fun! Its going to take me a while...I own a coffee shop down here and I dont have much time so I will be working slow.

 

[drivera84]

hi guys a little update.

The engine I had found...the deal didnt fall through ...

do any of you have a gs750e engine I could use...if you are in the miami area it would be great, I have someone here that could go pick it up for me and send it to me.

What other size engines (preferably larger) fit the 1978 gs 750e frame? Do the different engine sizes use the same carbs?

I am also contemplating the idea of rebuilding the engine I have...Any ideas as to how much its going to cost me? What parts Im going to need etc.

You can tell from the pics that most of the stuff I have is pretty rusted. The head and carbs are misssing in the pic but I have them...they could probably do with just a cleaning but I am not sure.

and advise is welcome....

thanks!

 

[drivera84]

yes.....that is water in the cylinder

 

[drivera84]

 

[Guest]

Ugh that looks horrible!

You can definitely rebuild that, you'll probably need some new pistons and I suspect you'll need a rebore of the cylinders and one or two size up rings etc.

The big question is what condition things like the cam and bearing journals are.

If they're not corroded and are still within spec then you should be good to go I would imagine, although I'm not an expert of course...

A replacement engine would be easiest of course, but I wouldn't say yours is a total loss either...

 

[drivera84]

I know pete...its not nice...

I tried taking the jugs off and the rods moved the crankshaft a bit...but the pistons did not move. What do you suggest to unstick these pistons?

 

[Guest]

I know pete...its not nice...

I tried taking the jugs off and the rods moved the crankshaft a bit...but the pistons did not move. What do you suggest to unstick these pistons?

Penetrating oil, WD, something along those lines... and lots of patience!

I'd probably pour/spray a heap down each cylinder and repeat that every day for a week or something and see if they let up on their own...

 

[drivera84]

I will post pics of the cams and carbs so you can see em..

 

[drivera84]

hi,

Well I started taking her appart to clean parts and see what needs replacing...after two broken skrew drivers (low quality tools) I decided to get myself an impact driver and maybe??? ($) some snap-on tools...

Im in the process of taking all the electricals appart, I have no expirience so Im working very slow, basically just cleaning everything and trying to figure out which wire is for what and where does it go. The two white relays?? under the tank, what are they?

Ive been reading in cliffs page and Im going to buy a multimeter to test if the stator and r/r needs replacing.

I am going to replace the engine so Im still looking for one...

 

[Hoosier Daddy]

Hello again, I posted in your introduction a while back. I'm glad I found your build thread. If I am thinking right, what you are calling the "The two white relays?? under the tank" are the coils. If they have the spark plug wires coming out of them.
I think with those cylinders and pistons looking that bad, you are going to need something pretty strong to get them apart. WD-40 wont do it. A good Penetrating oil might with a lot of patience as Pete stated. Being in Honduras I do not know what you have available. Try removing as much rust as you can, fill the cylinders with a 50/50 mixture of acetone a car automatic trans fluid and let it soak for a week. Heck even kerosene or diesel fuel will help, but I am afraind you may need to try something more acid, toilet bowl cleaner or even muratic acid (NASTY STUFF!) to get them loose. Then you will have to get the cylinders bored by a machine shop and buy oversized pistons. Might be cheaper to buy used parts but you still need to get it apart.
Good luck to you!

 

[Billy Ricks]

If you use acid then use diluted phosphoric acid. It will destroy the rust without damaging solid metal. And do whatever you have to do to keep it from seeping into the crankcase.

 

[Hoosier Daddy]

That brings up a good point... Keep ANY cleaners / debris especially acids out of the bottm end. If the top looks that bad, what condition is the crankcase internals looking in from the top? What was the oil drained out, partial water?
That will tell a lot as to if you would be best to just find a replacement.
Do not be discouraged, it happened to me as well on the '81 Goldwing. I wound up buying a parts bike that had a spare engine.

 

[drivera84]

Hi guys.

Im a fan of leaving her most like she came from factory (expect the cafe conversion part) I would like to keep the stock engine. I am looking for a replacement to get her running but will probabbly wind up rebuilding this one down the road. Oversized pistons have a nice ring to em...but that will be done later with more time. Im not sure if i will in fact find a replacement so I am working on this one.

Looking in from the top the crankase doenst look very rusty...but putting her on the side water seeped out and some milky looking substance (oily water?).

Also the rear wheel is stuck....even in neutral gear. I tried lightly pulling back on the kick start and it moved, just a tiny bit, but it moved so Im being a little optimistic on the crankcase. Ive been trying to remove the drain plug skrew (the one in the bottom used to remove the oil) but its stuck hard. Been spraying it to see if it loosens up.

The gas tank doesnt look so bad, the cap is very tight too...are there any tricks to get it off. Im a little worried because if I shake it it sound like some loose stuff in there...it could be just dirt but I think it might be rust

I would post some pics but ive been working at night, so they dont really show up nice.