i need more umph (85 gs 700es)

[Anonymous]

I own an 83 750es punched to 920. It is currently being redone from the frame up. I would argue that it would not be too difficult to go ahead and put a 1100 or 1150 motor in it. I have done some rough measuremenst with my 1100 and 1150 and everything seems too close not to try it. The research I have done on thsi is 50/50, half teh people I speak to say it will bolt right in, the other half say no. The person I put most stock into is a guy at the local track. I was standing in teh pits and asked him if the motor from that bike, I pointed at the 1100, would fit into the frame of that bike, I pointed at a nice 83 GS750ES. He said it will bolt right in. I have not fouynd anyone who has actually tried it. I know anything up to 1150 will bolt into a 750 up to the year 82 because I own one. But I am not sure on teh 83 and up 750E. Any opinions on this?

A little more far reaching is this theory. The other day I was looking at an article on a Bandit 1200. This may be way out there, but geez the frame and motor mounts look awfully close to that of a GS, which would not suprise me one bit. I have not been able to get to the local shop to take any measurements, but I would ALMOST, bet that a bandit 1200 motor will fit in a GS frame. Any opinions on this?

Thanks!
Mike

 

[Anonymous]

Just do what I am doing... buy a bigger engine, then beef on that :twisted:

 

[moto_dan]

I own an 83 750es punched to 920. It is currently being redone from the frame up. I would argue that it would not be too difficult to go ahead and put a 1100 or 1150 motor in it. I have done some rough measuremenst with my 1100 and 1150 and everything seems too close not to try it. The research I have done on thsi is 50/50, half teh people I speak to say it will bolt right in, the other half say no. The person I put most stock into is a guy at the local track. I was standing in teh pits and asked him if the motor from that bike, I pointed at the 1100, would fit into the frame of that bike, I pointed at a nice 83 GS750ES. He said it will bolt right in. I have not fouynd anyone who has actually tried it. I know anything up to 1150 will bolt into a 750 up to the year 82 because I own one. But I am not sure on teh 83 and up 750E. Any opinions on this?

A little more far reaching is this theory. The other day I was looking at an article on a Bandit 1200. This may be way out there, but geez the frame and motor mounts look awfully close to that of a GS, which would not suprise me one bit. I have not been able to get to the local shop to take any measurements, but I would ALMOST, bet that a bandit 1200 motor will fit in a GS frame. Any opinions on this?

Thanks!
Mike

I bought my '83 GS750es with the intention of grafting my '80 GS1100 engine in it since the 1100 was already sitting in my '81 GS750 chassis, but I can tell you it will not bolt straight up. The '83 and '85 750/700 engines are a couple of inches shorter from front to back and top to bottom than the previous 750 engines. You may be able to disassemble the top end of the 1100, put bottom end into chassis and then assemble the top end with engine in the chassis if your so inclined. I had one fellow that swore he did this, but the 1100 engine had to be tilted at an odd angle. I couldn't figure out how to do it cleanly so
I shelved the project. Now if your willing to cut the frame like on the early 1100 gsxrs then I believe you could fit the 1200 bandit engine, GS1100 or early GSXrR1100. I would love to have a 1100 or 1200 in my '83. Let me know if you figure out how.

 

[HiSPL]

I own an 83 750es punched to 920. It is currently being redone from the frame up.



What parts are you using to go to 920cc? Are you using a stroker crank? If so from where?

 

[Anonymous]

would love to have my 700 punched up a little bit anybody have any good ideas or about what i could take it to safely

 

[Anonymous]

axel what part of cincy are you in

 

[Billy Ricks]

I believe I might be able to get you a set of Cosworth forged 12:1 pistons to fit your bike.

 

[HiSPL]

How much for the pistons? And what size are they? Also do they fit the GS con rod? and do they have rings?
Thanks.

HiSPL@bigfoot.com

 

[Billy Ricks]

They are .05mm over which requires nothing more than a clean-up hone. They don't have rings and are not available. They are new and have never been used. I got mine from Britt Turkington years ago. It took me about 5 or 6 years to resolve the ring issue. I sent the pistons out to TotalSeal in AZ and they recut the top two grooves to accept a set of their Gapless rings which virtually eliminate ring blow by. They do fit the stock rod and have new wrist pins and clips. I'll have call Britt if you are serious. They would run over $1000 if you could even find a set. With what Britt wants and the work by TotalSeal you might spend $400 or so. The guy at TotalSeal said that what I ended up with between the pistons and their rings was very exotic.

 

[HiSPL]

what does 12 to 1 compression do for ya, as far as power?

 

[Billy Ricks]

Haven't installed them yet. I was needing a set of rockers before I went back into the motor. I finally got a complete head off of Ebay that I'm going to salvage parts out of to finish the job. I have a set of Vance&Hines modified grind cams that I'm going to install with them. I already have RS flatslides installed and a Yosh Duplex exhaust from an air-cooled GSX-R. The carbs alone make a huge difference. The combination of everything I'll have in the motor should make a huge difference. Stock hp is supposed to be around 80. I wouldn't be surprised to end up with 110-120 hp. The cams aren't as wild as a full road race grind and I won't have Carillo rods, though I'd love to find a set, but apart from that it will be close to Superbike spec from the period.

I'm kind of waiting to go back into the motor to see if I can get my hands on an '83 GS750 crank and rods to make it a full 750, mine is a 700. If I can find a crank I'll send it to APE for lightening and balancing. People will argue you lose some low end grunt, but when you increase your hp that much it will still probably have more bottom end than it does stock.

 

[HiSPL]

Sounds good, I'm going to give these pistons some serious thought. I need to see what other mods are in the budget if I go with 750 pistons. I have been planning on the big bore route, but this sounds interesting....I'd like to hear from you when you get your engine built to see what kind of power you get from it.

Thanks

 

[Anonymous]

Thanks, you guys

Thanks, you guys

I own a 1983 GS750ESD in pretty much stock (and mint) condition. After 19 years of ownership I was feeling pretty good that I personally just reconditioned the forks, including installation of Progressive Suspension fork springs. Based on some of the posts here, I now realize that what I did was minor and that the bar has been raised out of reach (turbo's, 920cc punch-outs and such). Thank's guys for for providing a dose of reality .

Simon Waters

P.S. The fork springs work great........also 212+ degrees is normal.

 

[Billy Ricks]

I own a 1983 GS750ESD in pretty much stock (and mint) condition. After 19 years of ownership I was feeling pretty good that I personally just reconditioned the forks, including installation of Progressive Suspension fork springs. Based on some of the posts here, I now realize that what I did was minor and that the bar has been raised out of reach (turbo's, 920cc punch-outs and such).

Simon,
Your bike looks pretty pristine for one that is 20 model years old. If I hadn't met up with Britt I probably would have never started modifying mine. Knowing him gave me a source for parts and great advice. For someone that had as much success racing as he did he is a very approachable guy with a great wife and kids. He has his own business going now printing shirts for Yoshimura, Dunlop, and quite a few other race connections. He also builds custom surfboards. He's never too busy to stop what he's doing and help a friend. One helluva nice guy.

 

[Anonymous]

Billy:

In case I didn't mention it before: thanks for your tips on seal changing and aftermarket fork spring installation......the plastic pipe connectors worked well as spring spacers.

I keep meaning to do a write-up on fork seal & spring work (when I have time!) but let me mention a couple of things now. The manual specifies using new inner (i.e. lower) "anti-friction" bushings when changing seals. This I did but they were in pretty good condition from the last seal change by my dealer 13,000 miles ago. What surprised me were the state of the outer (i.e. upper) bushings - they were really worn!! Since the service manual doesn't mention replacing these bushings as standard, I guess mine were the original items with 32,000 miles on them. Fortunately, I had new outer bushings as well, so this was not a problem. However, if your bike has substantial mileage, I would recommend to anybody that they be prepared to replace these items.

One more thing: I found that my bike's left, chrome (upper) fork leg had a couple of closely-spaced grooves/gouges. Since I thought that these might be responsible for the short seal life, I spent 2 hours with 220 through 1200 grade wet & dry taking them out. I never did remove them completely (now I really know why chrome is used....it's incredibly hard!!) but at least they no longer fail the "finger nail" test. I just didn't see the point of doing all this work just to leave a possible root of the problem present.

Simon Waters

 

[Anonymous]

Any of you guys familiar with JE Pistons of California? They specialize in custom pistons for motorcycles and automobiles. I'm having them make bigger pistons for my XN85 Turbo. Cost is about $650.00 and includes rings and wrist pins. Phone number is 714-898-9763.
Axel

 

[Anonymous]

im amazed at how similar the 85 700esf and the 83 750es look alike does anyone know whether or not the cylinder heads and pistons are interchangeable would they work if anybody has a clue let me know, because it seems like they still make alot of parts for the 750 vs the 700

 

[moto_dan]

im amazed at how similar the 85 700esf and the 83 750es look alike does anyone know whether or not the cylinder heads and pistons are interchangeable would they work if anybody has a clue let me know, because it seems like they still make alot of parts for the 750 vs the 700

The 85 700 and 83 750es are the same except for a few cosmetic changes and a different crank shaft. The cylinder, head, pistons and rods are identical. Suzuki shortened the stroke of the '83 750 via a different crankshaft to get the 85 700. There are not really any more parts for the '83 750e than the 700. One thing to be cautioned about is that Suzuki did make a 750T in '83 which is the left over physically larger 750(16v) first produced in '80 and parts from those engines are not interchangeable with the 700. Hope this helps.

 

[Billy Ricks]

The cylinder, head, pistons and rods are identical.

Actually the rods have to be a bit shorter and the crank pins moved out on the crank by the same amount. This allows the piston to end up at the same point TDC and be drawn down into the cylinder by that amount to increase the stroke.

 

[moto_dan]

The cylinder, head, pistons and rods are identical.

Actually the rods have to be a bit shorter and the crank pins moved out on the crank by the same amount. This allows the piston to end up at the same point TDC and be drawn down into the cylinder by that amount to increase the stroke.

Yep, sounds reasonable. Thanks for clarifying. I mainly wanted to communicate that many(including myself) intially reason that the differences between the two is the bore size when as you pointed out to me years ago it was the stroke. Another good example of why you were missed from the forums.