GS550E 78 big bore kit

[skreemer]

ha all the pictures are gone. I'll see if Nerobro still has them and I'll try and get him to put them back up.

[barrykatona]

weight loss problem

Hampshire hog I am rebuilding a 550 Katana and am interested in your comments about lightening the bike to gain better performance.Could you explain how/where weight could be saved?





one day this Kat will wail again

[hampshirehog]

Basically with weight saving it depends how much you want to spend or hunt around at bike jumbles. Most of it is incremental too so you can do bits and pieces as you go. From memory this is what I did to a GS550 a while back:

1. Harris Works pipe - I could have got lighter I'm sure but this was cheap second hand and had 'period' charm. Nice zorst note too.

2. Junk the pillion pegs and replace those heavy front pegs with alloy ones. Chop the frame mounts as they aren't needed now.

3. Alloy bars - you can pick some quite nice non branded ones pretty cheaply.

4. Fit spoked wheels rather than alloys. I was real lucky here as I was given (for free!!) an abandoned project that had brand new akront alloy wheels. I bet they cost a pretty penny but are a lot lighter (and it's unsprung weight too). And they looked lovely.

5. fit an alloy swing arm. I picked up one at a bike jumble that only needed a bit of filing to fit. Possibly a Kawasaki but as I'm not a Kwacker officianado that's only a guess. Again unsprung weight.

6. Chuck out the electric start and use the kickstart only. That thing's pretty damn heavy and this bike was a first time starter. (Not an option on a Katana as they took the kickstart off - shame). You can get away with a smaller battery as well now (I thought about going without a battery and running on a Boyer system I had kicking around but never got round to it).

7. Remove or replace the indicators with lighter ones.

8. Lower fork yoke is pretty heavy. I picked up an alloy one at a jumble - off another Suzuki but I'm not sure which one. A straight replacement with no mods.

9. Dump the airbox and fit pod filters - I'd only do it on VMs as I'm not convinced that CVs are suited to pods.

10. fit drilled discs - only a few grammes but it all helps. Could you run with a single disc up front? I did and never had any horrible moments. (The early bikes came with only a single anyway so I reckoned it was ok - cheaper on replacement pads too!)

11. Replace the front mudguard with a plastic one.

12. Braided brake hoses with alloy banjos- lighter and better than originals.

13. Take off the centre stand and just have it around for maintenance time.

I probably did a few other things but this was all over a period of a few years and it's dead simple and didn't cost a lot (although I was bloody lucky with the wheels). You can go mad and get titanium stuff and the likes but it's not in my mind good VFM. I wish now that I'd kept a record of weight changes between the original parts and how much I saved - it might not seem much individually but it all adds up.

Wally

[dfgood]

Gs550e

Thanks for the thought, the main reason I was looking at the Wiseco kit was the cost (all inclusive, pistons, rings, gasket etc)compared to OE, and a little bit of extra performance as a bonus.
It looks as though o/size OE pistons and rings are still available, but fairly expensive.

Thanks for the tips

[dfgood]

More on the GS550E

By the way, there's a picture of my bike in the gallery, its actually listed as a 500 (red one Darren Thorogood).
I took some weight off by using pod filters, plastic front guard, small alloy chain guard and plastic indicators.

One other thing, mine is the triple disc model, but the front brakes are useless, I put new pads on while ago but really didn't improve them much. I checked the master cylinder and calipers, all were ok, I even checked that the piston ratios were right. I haven't yet looked around for softer pad. Any thoughts would be appreciated on this one.

Thanks
Darren

[hampshirehog]

If your motor needs a rebore and new pistons then the Wiseco kit is worth doing - I was assuming that you were just upgrading (Rule no. 1 - never assume anything). You will notice a performance gain, especially if your current top end is a little tired. The GS650 top end is an alternative, though I've never done it myself and I'm not sure if you could fit VM carbs rather than CVs. (That could start an argument - I'm a dyed in the wool fan of VMs where you're in total control of what goes on down below and not what is effectively a take of the old British Leyland SU carbs - the very worst of 70s British motoring design which I could rant about all day...).

As for brakes, maybe my expectations aren't as high as others but I've always found the original spec reasonable and just ride knowing what they are like. Compared with modern stuff of course there is no comparison (though the best stopper I ever had was a GT250M, all original - stop on a sixpence). Decent pads are a must - you get what you pay for. Another thing that has worked for me is an annual (or 'every now and then') 'recon' of the discs. I reckoned that with them going all shiney and polished the friction would be down and using a rotary wire brush on a little angle grinder just lightly 'de-buff' the surface. I mean lightly as you don't want to wear the disc out too quickly or create an uneven surface. Be a bit wary of the first few bites on the brakes though as it can be fierce until it beds down a bit (a bit like the brakes on your car going rusty over a weekend if you've driven through a ford on the Friday night). And braided hoses - an absolute must.

On the subject of crap brakes my mate has just restored a 1954 New Hudson autocycle. Passed its MOT but god knows how - now that is seriously deficient in the brake department. The QE2 stops quicker.

Nice looking bike by the way - like the colour and nicely polished.

Wally

[Nessism]

VM carbs on the 550 are 22mm vs. 32mm for the later CV's. The CV's have the butterfly in the airflow but even so, they flow way more air than the VM's (ports in the head are larger as well) so they would be a better platform for the big bore kit in my opinion.

A big bore 550 sounds like a fun project but a little on the spendy side considering the low cost 550's go for - you will never get your money back in resale.

[Suzuki_Don]

ha all the pictures are gone. I'll see if Nerobro still has them and I'll try and get him to put them back up.

Hi SKREEMER, any idea when we can get the photos of the 650 conversion. Would like a copy of them if that is possible.

Cheers

Don

[hampshirehog]

The difference in size between the VMs and CVs isn't all that clear. The widest part of the CV is 32mm at the motor side of the carb, but the carb has a narrower middle section, where it is in fact quite oval in shape. The VMs, which are VM22s, are 26mm at the motor side of the carb but again with a narrower, oval centre. (I've got sets of both somewhere and ought to take some more measurements - might be interesting). It seems to me that Suzuki changed where they measured their carbs when the switched designs, possibly a marketing ploy (32s are bigger sounding than even the VM28s on a 1000). Honda did the same thing.

The obvious difference is how the 2 designs work. VMs are simple; open the throttle, the slide lifts = more fuel / air. With CVs you open the throttle, the butterflies open and as a result the slides lift. But the amount the slides lift depends on the pressure diiference caused by more air flowing through the body of the carb and this pressure is related to the draw on the airbox, or different draw if you run individual filters. This leads to all sorts of variables when swapping filters / jets etc and I've never found it easy to get CVs running sweet - might just be me as I've known others get it right (but I'm not so sure they admit to it being simple). VMs are a doddle - you have easy changes with jets and needle position and perhaps slide cutaway (ok, slide cutaway is tricky if its DIY).

I like simple 'cos I can at least pretend I understand it.

Wally

[brveagle]

Hi SKREEMER, any idea when we can get the photos of the 650 conversion. Would like a copy of them if that is possible.

Cheers

Don

Pictures didn't do it for me. If you know how to rebuild a gs engine, you'll have no problem. I learned every step of the way and glad i did. Pretty much just remove the 550 top end and replace with the 650 top end. The hardest part for me was the grinding i had to do on the lower end to get the 650 cylinder "jug' to slide down into the mouth's of the 550 lower end.

[Nessism]

The difference in size between the VMs and CVs isn't all that clear. The widest part of the CV is 32mm at the motor side of the carb, but the carb has a narrower middle section, where it is in fact quite oval in shape. The VMs, which are VM22s, are 26mm at the motor side of the carb but again with a narrower, oval centre. (I've got sets of both somewhere and ought to take some more measurements - might be interesting). It seems to me that Suzuki changed where they measured their carbs when the switched designs, possibly a marketing ploy (32s are bigger sounding than even the VM28s on a 1000). Honda did the same thing.


Wally

I agree that the difference is not as great as the listed measurements would lead one to believe. Suzuki lists the same horsepower for the VM equipped engine as the BS/CV carb engine. In actual usage though, my experience is that the CV engine is quite a bit peppier. The engine ports are clearly larger so that might have something to do with it.

[Suzuki_Don]

Pictures didn't do it for me. If you know how to rebuild a gs engine, you'll have no problem. I learned every step of the way and glad i did. Pretty much just remove the 550 top end and replace with the 650 top end. The hardest part for me was the grinding i had to do on the lower end to get the 650 cylinder "jug' to slide down into the mouth's of the 550 lower end.

I have never rebuilt a GS engine but have rebuilt many others. Just trying to do all my research before I dish out the big bucks and start looking for a 650 top end. Its good to read your comments though and be reassured that the task is quite straightforward.

Cheers
Don

[brveagle]

I have never rebuilt a GS engine but have rebuilt many others. Just trying to do all my research before I dish out the big bucks and start looking for a 650 top end. Its good to read your comments though and be reassured that the task is quite straightforward.

Cheers
Don

http://www.thegsresources.com/_forum/showthread.php?t=89845

[Suzuki_Don]

Thanks BRVEAGLE. Will a 4 valve cylinder head fit or is that going too far.

[brveagle]

Thanks BRVEAGLE. Will a 4 valve cylinder head fit or is that going too far.

well there are no 4 valve per cylinder 650's...

and a 550 4 valver might mit but it's not practical as the pistons are still 2 valve.