Noob needs wants to talk about 7/11 motor swap!

[Kawazacky]

Hey fellows,

My boss wants to give me his GS750/1100 project. The bike is mostly there as a 750 rolling chassis with 1100 engine installed (and GS650 front end w/double disc brakes!), wheels, 4-1 exhaust, etc. are all there.

It needs carbs and a wiring harness, along with some other minor bits that won't be complicated, I hope (stuff like fork seals).

My main sticking point is the carbs and harness, though. I'm pretty sure he has a set for the bike, but I don't know where to start when it comes to jetting them, as I've never had a GS before and don't know the common settings. I also don't know if it would be better to adapt the 750 wiring harness to the 1100 ignition, or adapt the 1100 ignition to the 750's headlight/taillight/indicators.

Where's the best place on here to get more information about this sort of thing - here in the mods section, or in the carb/electrical subsections? I know I'm not the first guy in the world to do this sort of swap.

[SqDancerLynn1]

Wiring and ign depends on what years they are. Jetting ? what were the carbs from ?
The garage lists some of the more common jetting specs -here-- http://www.thegsresources.com/_forum...ad.php?t=73723 These are stock specs, with pipe and Pod? filters It is mandatory to rejet

[Kawazacky]

Wiring and ign depends on what years they are. Jetting ? what were the carbs from ?
The garage lists some of the more common jetting specs -here-- http://www.thegsresources.com/_forum...ad.php?t=73723 These are stock specs, with pipe and Pod? filters It is mandatory to rejet

I think they're 1100 carbs, and I think the engine is an '82? It has the 16-valve head.

The frame itself is a '77 or '78, I believe.

[BassCliff]

Greetings and Salutations!!

Hi Mr. Kawazaky,

Jetting will depend on the intake and exhaust setup. There are basic guidelines but plug chops will be necessary to fine tune each particular carb circuit. Generally, with quality pods and 4-n-1 pipe, start with one size up on the pilot jet, 4-6 sizes up on the main jet, and shim the needles to raise them a little bit to richen up the midrange. You'll find quite a bit of carb information on my little website and by searching the forum.

Anyway, let me dump a TON if information on you and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Rebuild Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. Now let me roll out the welcome mat for you...



Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[Kawazacky]

Thanks for the welcome.

I'll check that stuff out when the bike shows up.

If I get it, I'll be putting it together for an online mag, so you guys can keep close tabs of the build....

[zackurylyk]

Well first things things first - this project hasn't happened yet. I've had a lot of changes with my job, as well as renovations, chewing up my time. I significantly overhauled my DR650 last winter, and didn't have time for much else.

(BTW, as you can see, I had to create a new ID on here).

ANYWAY.

I'm now working full-time for Rob Harris, editor-in-chief at the Canadian Motorcycle Guide (wwww.cmgonline.com).

He still has the half-completed 7/11 project in his garage, and said I can take it with me when I leave the office to return to part-time from home at the end of the summer. If I can get the thing running, we'll put the bike's story on our website. It's a bit of a legend with our site's readers - he started the project over ten years ago, and just never got around to finishing it.

He actually found the 1100 engine in a parts bike leaning against a back alley fence, asked the owner if he could have it, and was told yes. He got it to turn over, but never ran it before he installed it in the 750's frame.

This has led me to some serious thinking about this project in the last few days. As long as that 1100 motor runs, half the hard work has been done already, if I want to go the 7/11 route. The 1100 engine is in the frame, and the lower motor mounts have been made (ALTHOUGH Harris says he thinks they're a bit flimsy, and could be re-made).

There are, however, several key things to complete.

1). I need to install the 1100 carbs. Since they won't mate to the GS750 airbox, that means I'll need to fit some pod filters and re-jet. This can be both good and bad - pod filters means more airflow and easier removal for adjustment, but it also means (I have been told) worse running in the rain and wind, and I'm the kind of guy who runs a lot in the rain and wind.

CAN ANYBODY GIVE ME ANY INSIGHT INTO THIS? How hard will it be to re-jet these carbs for pods (possibly K&N, or whatever else works best)? (I've rejetted carbs for thumpers before, never for an I4)

Will I need to make a bracket to hold the carbs in the frame, or will the engine's intake boots be enough to secure them? Will the bike run rough in poor weather conditions?

2). The bike has the front end off a GS650 (cleverly chosen for its double-disc front end). This would likely be too puny for the increased power of a 16-valve 1100 motor. Would a simple fork brace solve most of this problem, or should I also be on the lookout for a beefier front end to drop in (maybe a GS1000 front end?)? I assume I'll be able to swap out the triple trees from a GS1000 directly into the 750?

3). I've already asked this, but what possible complications will I have when fitting the 1100 wiring harness to the machine? Seems to me that as long as the headlight will plug in (more or less), everything else should be easy, as long as I can find a place to bolt the R/R, CDI, flasher box, etc. to the machine.

Of course, it would be a shame to do all this and find the 1100 motor needed transmission work, and I imagine that after not running for probably 12 years at this point, it likely should have the top end popped off to examine the bore for rust.

NOW TO COMPLICATE THINGS ....

I also have the option to buy an (allegedly) running '86 GS750 parts bike (no bodywork or seat, but everything else is there) for $600ish locally. The owner says he can get the bike running for me if I go to look at it.

Would it be wiser for me to put that motor in the bike instead? I assume that:

1). The engine should bolt right in.
2). The '70s-era GS750 frame I will be using would be much happier with the '86 750 engine than it would be with the 1100 engine.
3). The 750 engine should be easier on gas than the 1100 engine.

Furthermore -

1). I'm wondering if the '86 front end (and maybe even swingarm) will bolt on to the '70s era frame?
2). Will that '86 frame take the 1100 motor? I assume not.

I realize these are a lot of questions. However, I know that many guys on here have asked all these questions before, and figured them all out. I've used the search function quite a bit, but

Can anyone help me?

[gearhead13]

The 1100 engine wont bolt into a 3rd gen frame. In '86 wasnt the GSXR out? Didnt know there was an '86 GS750.
Get a dynojet kit for the carbs and order new o-rings and K&N pods.
The '86 front end might swap ok, but the rear would be much harder because of the monoshock. Best or easiest thing would be an 80-83 1100 alu swinger.

[zackurylyk]

The 1100 engine wont bolt into a 3rd gen frame. In '86 wasnt the GSXR out? Didnt know there was an '86 GS750.

Yeah, it was the model with the quarter fairing. Quite a few of them around here - Canada - had the full fairing. Our model years are a bit different from the U.S.

The '86 front end might swap ok, but the rear would be much harder because of the monoshock. Best or easiest thing would be an 80-83 1100 alu swinger.

I'm kind of gathering that after researching on here. I think the 1100 swingarm is in the bike, but there's no bushing for it to make it fit. I don't fancy drilling the frame, so I was wondering if anyone on here sold the bushings?

[gearhead13]

Ya, was thinking you might be from Canada or maybe Europe. US models were 700cc.
Personally I drilled my frame, lots of meat there, and you get to use the bigger diameter 1100 swinger bolt instead of messing with spacers.
I havent heard of anyone selling bushings.

[zackurylyk]

Did you take it to a machine shop with a drill press, or did you do it by hand? I do not have a drill press myself ...

[gearhead13]

I used a good drill and carefully drilled. One side then the other, check that the bolt goes through properly before trying to mount the swinger. Maybe a little angle adjustment to make sure they line up. I didnt use a metric drill bit there is a standard size that is a good fit, cant remember what size it was.

[zackurylyk]

Hrm. Well I think my father in law has a drill press I might be able to use. I'd feel much more comfortable with that, than a hand drill.

Did you change anything on the front end with your conversion?

[7981GS]

You might want to look through this thread: http://www.thegsresources.com/_forum...d.php?t=195201

Eric

[zackurylyk]

Thanks!

I've spent quite a bit of time with the search function, but sometimes all it returns to me is a string of gibberish.

[gearhead13]

If you can find a big enough drill press to use and also get the original hole perfectly vertical then go for it.
I swapped the forks and triples from an '82 1100EZ, 37mm forks vs 35mm.