Honda-SOHC

SOHC.co.uk Forums => Other Bikes => Topic started by: AndyH on February 12, 2018, 09:26:54 AM

Title: Adding a GS750EC to the stable!
Post by: AndyH on February 12, 2018, 09:26:54 AM
I despaired of finding a CB750K that wasn't totalled, or vastly overpriced....not many for sale in AUS anyway.
So I've happened across a very nice & original '78 Suzuki GS750E  (the "C" suffix in subject line denotes model year).
Apart from a couple of paint chips on the tank, and a small dent, this bike presents very well indeed!
I've already taken it for a test ride and everything seems as it should.

Title: Re: Adding a GS750EC to the stable!
Post by: hairygit on February 12, 2018, 09:31:28 AM
Nice find in that condition. Be interesting to see how easy or not spares are to come by for it when the need arises compared to Honda bits. Enjoy it!
Title: Re: Adding a GS750EC to the stable!
Post by: Laverda Dave on February 12, 2018, 10:19:25 AM
That's a very nice looking bike. It also has a 'spare' camshaft  ;).
Title: Re: Adding a GS750EC to the stable!
Post by: mickwinf on February 12, 2018, 12:36:31 PM
very nice!
Title: Re: Adding a GS750EC to the stable!
Post by: Sgt.Pinback on February 12, 2018, 05:27:32 PM
Yes that looks great. Congrats, rare find in this condition.

Still genuine exhaust?
Title: Re: Adding a GS750EC to the stable!
Post by: philward on February 12, 2018, 06:12:36 PM
They are a great looking and very capable 70's era bike - I have looked at them to restore as they are so much more affordable than SOHC 750's (at the moment) - interested to see what the availability and price of spares is like. I had one of the first GS1000HC's in 78 - brilliant bike
Title: Re: Adding a GS750EC to the stable!
Post by: MarkCR750 on February 12, 2018, 07:09:45 PM
Great looking bike, they had good reviews when new, enjoy.
Title: Re: Adding a GS750EC to the stable!
Post by: royhall on February 12, 2018, 08:26:42 PM
They are a great looking and very capable 70's era bike - I have looked at them to restore as they are so much more affordable than SOHC 750's (at the moment) - interested to see what the availability and price of spares is like. I had one of the first GS1000HC's in 78 - brilliant bike
Just about finished renovating my 1978 GS1000HC now. They may be cheaper to buy but the parts prices can be eye watering. They are way more expensive to restore than a Honda.

Fantastic 750 though, are the silencers pattern as they dont look genuine Suzuki (to be fair though, as a 1000 owner I know little about the 750). O Bugger, I want one now.
Title: Re: Adding a GS750EC to the stable!
Post by: philward on February 12, 2018, 09:00:16 PM
Roy, can you get the likes of things like silencers, etc?
Title: Re: Adding a GS750EC to the stable!
Post by: royhall on February 12, 2018, 09:26:02 PM
Roy, can you get the likes of things like silencers, etc?
There are pattern silencers available from Italy. Dare say the chrome won't be long lasting as per usual Italian? I had to go the stainless 4 into 1 route as I don't have a correct set of genuine header pipes. I have been looking for a set for over a year now and none whatsoever have come up for a 1978 model. They all appear to be for the later L & GL models which are different. Parts wise, the 1000 is very well supplied as it's in the official Suzuki vintage parts program but the prices are around double that of Honda's. That said they are genuine Suzuki and very good quality.
Title: Re: Adding a GS750EC to the stable!
Post by: Rob62 on February 12, 2018, 10:15:40 PM
Great looking machine, one of the fastest 750’s in its day.... nice find!
Title: Re: Adding a GS750EC to the stable!
Post by: AndyH on February 12, 2018, 11:31:09 PM


Fantastic 750 though, are the silencers pattern as they dont look genuine Suzuki (to be fair though, as a 1000 owner I know little about the 750). O Bugger, I want one now.

Yes the silencers are pattern, from Italy.  The pipes are original, re-chromed.
Title: Re: Adding a GS750EC to the stable!
Post by: royhall on February 13, 2018, 08:08:53 AM
Great find Andy lovely bike, I want one now. I have a pair of Italian silencers in the garage for my 1000, if only I could find a set of header pipes. Don't mind re-chroming them as long as they are undamaged, just cannot find any.
Title: Re: Adding a GS750EC to the stable!
Post by: AndyH on February 13, 2018, 10:49:42 AM
Keep searching Roy, you never know what might pop up! :)
Title: Re: Adding a GS750EC to the stable!
Post by: K2-K6 on February 13, 2018, 01:05:15 PM
https://www.ebay.co.uk/itm/Suzuki-GS1000-GS1000-1978-On-Rare-Original-Exhaust-System-Silencers-Downpipes-/351885440976?hash=item51ee01b7d0

Of any interest Roy?
Title: Re: Adding a GS750EC to the stable!
Post by: royhall on February 13, 2018, 05:08:12 PM
https://www.ebay.co.uk/itm/Suzuki-GS1000-GS1000-1978-On-Rare-Original-Exhaust-System-Silencers-Downpipes-/351885440976?hash=item51ee01b7d0 (https://www.ebay.co.uk/itm/Suzuki-GS1000-GS1000-1978-On-Rare-Original-Exhaust-System-Silencers-Downpipes-/351885440976?hash=item51ee01b7d0)

Of any interest Roy?
Thanks for that. My ongoing eBay search pulled that one up. Unfortunately DK's says the link pipes are very rusty and thin. Seen quite a few of these and they are all the same. I think the water from the engine must sit in the link pipe and rot it away. At some point a good set will turn up off a bike that was written off in 1979 and stored in a dry garage. Some hope eh. ;D

DK's also have these for sale, dented and bashed all over. A snip at the price. https://www.ebay.co.uk/itm/Suzuki-GS1000-Circa-1978-1982-4-Into-2-Exhaust-System-Silencers-Pipes-DGM33922S-/332537921621?hash=item4d6cce0055 (https://www.ebay.co.uk/itm/Suzuki-GS1000-Circa-1978-1982-4-Into-2-Exhaust-System-Silencers-Pipes-DGM33922S-/332537921621?hash=item4d6cce0055)
Title: Re: Adding a GS750EC to the stable!
Post by: philward on February 13, 2018, 06:04:21 PM
I very nearly bid on this Roy - went for only 3 1/2 rusty exhausts!
http://www.ebay.co.uk/itm/1978-Suzuki-GS1000-Unregistered-US-Import-Barn-Find-Classic-Restoration-Project/312058673822?hash=item48a8257a9e:g:ZyoAAOSwPypadFSz
Title: Re: Adding a GS750EC to the stable!
Post by: royhall on February 13, 2018, 06:54:42 PM
Probably worth that money Phil, about what I paid for mine (3k). Looks like a good one but the USA seat and handlebars would have to go. Why is it whenever you put a bike back on the road the exhausts are always a pain.
Title: Re: Adding a GS750EC to the stable!
Post by: K2-K6 on February 13, 2018, 07:53:57 PM
It's usually acid as well in the water that sits in the lowest part of the pipe Roy, so no wonder that most older stuff rots.

I found reference and pictures of some repro original design in searching that states "made in double skin thicker guage" with some pictures but couldn't determine if they'd been produced for sale or he'd just had a set produced as one off.

Edit,   also this one. Seems to be in denver http://www.ebay.ie/itm/80-SUZUKI-GS1000-GS-1000-EXHAUST-MUFFLERS-HEADERS-XE47/352266267137?hash=item5204b4aa01:g:kMMAAOSw8H1abNpB

Looks move solid.
Title: Re: Adding a GS750EC to the stable!
Post by: royhall on February 13, 2018, 08:15:21 PM
The exhausts changed in 1980 so not 100% sure they will fit. Also the centre pipes became bolt on instead of welded?

Andy. Really sorry mate I appear to of accidently hijacked your thread.
Title: Re: Adding a GS750EC to the stable!
Post by: K2-K6 on February 13, 2018, 09:07:02 PM
On that note,  looks like you've got a nice example for yourself Andy.

I remember they arrived with road tests saying they'd get to 133mph,  I think,  pretty quick by any standard at the time.

Interesting link of the development here
https://www.cycleworld.com/suzuki-gs750-and-gs1000-motorcycle-history-cycle-world-classics-remembered#page-5


Title: Re: Adding a GS750EC to the stable!
Post by: philward on February 13, 2018, 09:35:48 PM
I remember when Paul Dunstall was selling standard GS1000 Exhausts for buttons in the early 80's - as he was producing Dunstall GS1000's and fitting his own (very load) systems. I changed my HC for a shaft drive G in 1980 (backward step as it happened) and bought one for the G when the exhaust rotted (had to mod slightly)
Title: Re: Adding a GS750EC to the stable!
Post by: Bryanj on February 14, 2018, 07:24:04 AM
The reason Paul was changing the exhaust was because it made them a "Dunstall Suzuki" which could be re crated and sold to Japan where they were not allowed anything over 650 at the time unless it was an import---he also fitted English tyres and sold the Japanese 450/17's cheap, the shop i worked at bought loads
Title: Re: Adding a GS750EC to the stable!
Post by: AndyH on February 15, 2018, 09:06:23 AM
Silencers on the GS750 are Marving.
Here's a couple more pics.  Bike will be in my physical possession this w/end or early next week....can't wait!  :)

Title: Re: Adding a GS750EC to the stable!
Post by: royhall on February 16, 2018, 08:34:32 AM
That is a cracker of a bike Andy. If it runs as well as it looks you have found a real gem.
Title: Re: Adding a GS750EC to the stable!
Post by: AndyH on February 16, 2018, 10:43:11 AM
Thanks Roy,

I see you have a GS1000 as a project bike...should be superb when it's finished!  :)
Title: Re: Adding a GS750EC to the stable!
Post by: royhall on February 16, 2018, 01:03:53 PM
It's just about done Andy. Just needs setting up etc and tank/side panels back on. Just really need a full day at it to get it all spot on. Will post some pictures when it's done.
Title: Re: Adding a GS750EC to the stable!
Post by: royhall on February 16, 2018, 06:20:22 PM
Wow an S model (ice cream van), that's the one to have. Looks like it needs the full works James.
Title: Re: Adding a GS750EC to the stable!
Post by: Bryanj on February 16, 2018, 07:11:52 PM
looks like a piper on there, leave it on and wake the neighbours-----in the next county!
Title: Re: Adding a GS750EC to the stable!
Post by: Laverda Dave on February 17, 2018, 03:05:11 PM
John Naish of Classic Bike was in the process of undertaking a rolling restoration of one of these big Suzuki's in the same colour. Unfortunately CB appears to have undergone a bit of a clearout in the past couple of months with John Naish, Mike Nicks, Mark Gardiner and Mick Duckworth all appearing to have left and with them the progress of the Suzuki rebuild.
Title: Re: Adding a GS750EC to the stable!
Post by: royhall on February 18, 2018, 10:21:03 AM
James. Your going to have fun getting the airbox and carbs off and on. If you find an easy way to do it you will let me know. Also, there's a really good clutch basket fix that stops the rattling completely using Falicon springs and welded rivets.

Sent from my Nexus 6 using Tapatalk

Title: Re: Adding a GS750EC to the stable!
Post by: royhall on February 18, 2018, 06:51:43 PM
Ah you've heard about the Falicon mod then James, all I can say is it really does work. The clutch on mine now makes zero noise, shame there's not a similar fix for the CB750 mine drives me mad.
Title: Re: Adding a GS750EC to the stable!
Post by: Woodside on March 28, 2018, 06:43:13 PM
just seen these and it reminded me of  this thread

m.carandclassic.co.uk/car/C976025
Title: Re: Adding a GS750EC to the stable!
Post by: K2-K6 on April 26, 2018, 10:25:37 AM
Ah you've heard about the Falicon mod then James, all I can say is it really does work. The clutch on mine now makes zero noise, shame there's not a similar fix for the CB750 mine drives me mad.

Royhall, have you been through the Honda routine for setting the carb idle jets to stabilise the tickover? When you hear some of them which are well set up they do sound much smoother as you've effectively taken out that hunting from running too rich at tickover. Even if it's one cylinder they just keep "chuntering" which makes the primary drive flap around.

This is what current fuel injection on cars does,  both diesel and petrol,  they optimise the fuel amount on tickover while monitoring individual cylinder speed via flywheel sensor,  so they have effectively mimicked Honda practice albeit with on the fly monitoring. That's why when you start modern stuff you get that flat very stable idle immediately.

The idle screws are set as a baseline by turns out figure given as start point and should be set properly when warmed up and running.

It may get you closer to what you're after on the Honda.
Title: Re: Adding a GS750EC to the stable!
Post by: royhall on April 27, 2018, 10:45:48 AM
Ah you've heard about the Falicon mod then James, all I can say is it really does work. The clutch on mine now makes zero noise, shame there's not a similar fix for the CB750 mine drives me mad.

Royhall, have you been through the Honda routine for setting the carb idle jets to stabilise the tickover? When you hear some of them which are well set up they do sound much smoother as you've effectively taken out that hunting from running too rich at tickover. Even if it's one cylinder they just keep "chuntering" which makes the primary drive flap around.

This is what current fuel injection on cars does,  both diesel and petrol,  they optimise the fuel amount on tickover while monitoring individual cylinder speed via flywheel sensor,  so they have effectively mimicked Honda practice albeit with on the fly monitoring. That's why when you start modern stuff you get that flat very stable idle immediately.

The idle screws are set as a baseline by turns out figure given as start point and should be set properly when warmed up and running.

It may get you closer to what you're after on the Honda.
Thanks for that. The carbs are synced quite well. They are spot on at tickover and very very slightly out at 5000rpm. Have had a play with the idle screws but it does not appear to make any difference to the clutch noise and the engine runs best at standard basepoint settings. Plugs are the correct colour as well. The clutch is rebuilt with all new plates/springs/bearings etc. I think this problem appears to be slightly worse on the F2 than the K's, I had another F2 and that was the same so think it may be PD carb related. Would be interested to know if the K7 does the same. The noise completely disappears when the clutch is pulled in so will just live with it.
Title: Re: Adding a GS750EC to the stable!
Post by: K2-K6 on April 27, 2018, 08:46:05 PM
I understand where you've got regarding syncing the carb slides but believe Honda go further onto the pilot setting to finish the setup.

It's not the clutch that rattles on these and generally all the 750s are the same I feel. When you pull and hold the clutch lever it isolates the gearbox which becomes stationery if the clutch is held open. With the clutch left alone,  the gearbox is left to oscillate in response to changes in crankshaft speed.

The Honda routine is such a benign piece of text that it's easily missed as to its true purpose. But I feel it's worth expanding to give a better assessment of what they are doing. I've come back to it and realised only after working on other things what they are achieving.
It's not an absolute setting of pilot jets (they give a start point for the F2 of 1 3/4 turns out) but accepting through their process the individual calibration of each idle circuit. This would take into account any physical difference in each jet and also how each cylinder is burning the mixture it's tgiven. And hence an equilibrium of piston speed when fired at tickover.

The crank speed,  if for example one cylinder requires a slightly different set point,  would speed up or slow down on that cylinder's power pulse. It's this effect that makes the crank speed oscillate,  and so makes the transmission clatter. Remember, you're altering the mixture via fuel quantity as you've already set the air via syncing.

They start by warning not to change the idle screws,  but if you've stripped the carbs and rebuilt,  then advise to follow this routine to set them again to factory spec.
So it's quite likely you'll end up with an aggregated level the same as you feel is correct now,  but with each cylinder calibrated to work with the true flow achieved through individual circuits, giving even combustion for all cylinders. And not an even turn of the screwdriver.

It's a bit like we set tappets. You could touch them all down to no clearance,  then back them out a pre-determined amount. But we don't do that,  we measure them with,  in effect a calibrated shim. Their routine is just doing that but with engine rpm as the calibrator.
Title: Re: Adding a GS750EC to the stable!
Post by: yozzer74 on May 12, 2018, 05:47:44 PM
Nice looking bike .I can agree with royhall the parts are eye watering bout ,two inlet rubbers for my gs550 yesterday 80 quid ooch
Title: Re: Adding a GS750EC to the stable!
Post by: AndyH on June 20, 2018, 11:49:35 AM
OK some interesting reading folks.....but back to the Suzi  :P....I've been on a few rides over the late Summer/Autumn here in West Aus and the bike has certainly lived up to expectations!  It has this lovely howl as you open the throttle at highway speeds but it's a cold bitch first thing in the morning!  ::)
I get positive comments wherever I take it so pretty chuffed!  8)
It does need the odd few things updated/repaired but as a basically unrestored/original example it's pretty good!  Winter is here now so rides will be less frequent so once I finalise some oil seal replacements on my Honda CB500K1, it will soon to be up for sale, and funds from this will go to updating the Suzi.
SimplePortal 2.3.5 © 2008-2012, SimplePortal