GS550 with SRAD Carbs

[DF217]

Hi,

I have an old GS550 that I hope to restore in the future but for now, well last week I bought a 1978 GS550E - it has SRAD Carbs fitted and the bike seemed fine for the first 3 days, rode home about 90 miles and went out for the next few days and no real problems.

Fourth day didn't get out on it - Fifth day the bike was leaking fuel from the K&N air filters and was running badly, getting worse throughout the day - ticking over seemed to be erratic - was revving itself and then stalling on tick over.

Sixth day bike was running too rough to ride and any confidence in it so stripped it down under the belief it could be fuel contamination and a sticking slider / float. Upon stripping it down it down it was evident that the rubber inlet manifolds were torn and were leaking air.

I have managed a temporary repair on these but the carbs do line up with the inlet rubbers so it's putting them under strain so likely they won't last too long. I have an original set of GS carbs and was going to try these but when I stripped the SRAD carbs off it became evident that the inlet rubber were far too large for the original carbs.

I'm just wondering if any body has successful used SRAD carbs on a GS550 and what they used to get round the fact the inlets don't line up? Or if anybody is aware of any after market, custom or inlet manifolds / boots off other bikes that would make this possible to align?

Any help would be appreciated as spent the last few evenings / nights trying to get this figured out and get the bike running again!

Thanks

David

[BassCliff]

Greetings and Salutations!!

Hi Mr. DF217,

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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 Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. 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!

More links to helpful threads in the forum:
Help! Your Bike Won't Start
DON'T DO THESE THINGS
Help! Your Bike Won't Run Well
Oh God! Pods!


Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[OldVet66]

Suzuki Ram Air Direct. How would a system like that work on a '78 550? I'm assuming they are carburetors off a GSXR without the ram air system. CV carbs? The best way to get help would be to get new boots for the old VM22SS carburetors, rebuild those and go from there. If you have the old air box that would be a real plus but if you don't you would have to re-jet for pods. That would still be more familiar territory than trying to fit oversize CV carburetors to the motor. Later model 550's used BS32SS CV carburetors. Suspending the Carburetor rack from the frame would take the strain off the boots if you could manage to get a good seal on them, but the whole system sounds cobbed together at best. Must have been a pretty good cob job to make it 90 miles with no problems though.

[DF217]

Hi BassCliff

Thank you so much for all the information it is really helpful and given me a great plan to follow to make sure I get everything done that needs doing but in the right order - will take some time to get through it all but top notch information and I am sure it will save me hours in the long run!

Thank you

David

[DF217]

Hi OldVet

Thank you for the reply - it is a very odd 'cob job' but when I first bought the bike it seemed to run lovely, although I only got a couple of hundred miles out of it at best!

In the long run I agree that it may be best to go back to stock and I have a set of 'original' carbs with the bike and also a set at my parents so I'll follow the strip down guides and try and get these sorted and get the original inlet rubbers ordered.

Could I ask as a lot of GS / GSX's that I have seen have K&N / pods is there much advantage to these or would you say back to stock air box is better and why? Also it has a Motad 4 into 1 if this has any influence on the pods?

In the meantime I am going to see how well I can get it running with the SRAD carfbs so will let you know how I get on.

Thanks

David

[hjfisk]

Jetted properly there is no reason the slide carbs won't work. Get new intake boots and go from there. With them if jetted properly you should have better throttle response .

[OldVet66]

I have a 4-1 pipe and pods on my bike. If I had known better at the time, though, I would have kept the stock air box. Jetting for pipes and pods can be a PITA because you have to compensate for so much extra air flow because of the pods. Having said that I have learned how to do it and get a solid 41MPG and 44MPG when I'm a bit easier on her. It lightens up the bike a bit and there is probably some gain at the top end but it makes it harder to tune for good low speed manners. Jetting for pipes alone is a lot easier and you would probably have a smoother bike for less trouble and expense. It definitely makes working on the carburetors easier though and looks better IMHO. It would be one of those personal choice questions. The 4-1 pipes and pods together theoretically give better air flow. I would be interested to hear how the present carbs work out. Once you get them set, tying the rack off to the frame aught to keep the weight to a minimum on the boots. Pictures are required.

[DF217]

It's been a busy few weeks but got there in the end!

Hi Guys,

Thanks for the replies and all your help, sorry for the delay but I haven't been spending much time on the computer as I've been spending most of my spare time on the bike trying to get it running and just thought I'd post back now with an update.

To start with these were the inlet rubbers that were originally on the bike but I don't think they are original GS550 as I think the carb side is a larger diameter, they don't seem to match up with the two variations available for the CV or Slide carbs on the 1978 GS550E so this was causing problems trying to get replacements:



As you can see they were quite badly split. I was able to make a temporary repair with super glue and self amalgamating tape but this was only good for approx. 50 miles at a time:



Another issue was that although the inlet rubber manifolds matched up with the bores on the cyclinder block and also the carbs they were really out of alignment and I had quite a job getting the misalignment sorted - I think theis may have been the reason the rubbers split in the first place:



So I did a bit of research and bought some second hand inlet rubbers for GSXR's and Bandit to see if they would be a better alignment and fit .... and the GSXR 600 SRAD inlet's from the mid nineties model's which match the carbs also seemed to give a better alignment:









Then everything seemed perfect but I couldn't get the bike to start properly or run or idle - everything seemed fine but obviously wasn't so I tried copper instant gasket on the cylinder gaskets and tried instant gasket on the carb side to try and eliminate any leaks but the bike just did not want to start or run properly!

At this point I repaired the old inlet rubbers again to eliminate any other issues, I was checking fueling, sparks, ht leads etc .... but with the old inlet rubbers repaired it worked beautifully .... so after a week I then replaced the GSXR inlet rubber 'o' rings and the bike came back to life, it ran, it ticked over, and everything is coming along and getting back on track.

Since then I have changed the oil and filter, spark plugs, front pads (bleed nipples took a while to free off!) and I just thought that I would add the GSXR inlet rubber manifolds seem much more hard wearing and robust and during the last few weeks I also tried some GSF 600 Bandit rubbers but they were well out of alignment for the GSXR carbs but may make a suitable replacement for the original carbs as the rubber is a lot hard.

Anyway, like I said originally just thought I'd keep you guys up to date and thank you again for your help at the start, the resources that you sent over will give me something to read up on and hopefully keep this GS running for many years to come!

Thanks

David

[hjfisk]

Try covering the air intake side of the carbs with a couple layers of shop towels, if you are trying to start and run it with out an airbox , it's not going to happen you need some restriction there, your getting way to much air

[BigD_83]

Sorry, but I can't help with any ideas on your current situation.

However, in your first picture, you can see that Carb boot #2 is upside down (the vacuum port is up and to the inside instead of down and to the outside), and looks to me like it might be a right boot, not a left. That could definitely promote stretching/torquing, and eventually tearing.

[DF217]

It's all good!

It's all good, the bikes running fine with GSXR inlet rubbers, Thanks.

[OldVet66]

Glad to hear you got it sorted out. Are you going to use pods on the carbs or just screen them?

[DF217]

It already had pods fitted and the jetting seems fine as the bike seems to run pretty well now. They have used the old rubbers from the original airbox and joined these to the pods so that the outside pods fit on an angle and fit the bike well. I'll take some photos and post on here so you can see what I mean.

One thing is that the pods are not completely sealed on the join to the original rubbers - do you think this would alter the jetting running etc if I was to seal these completely to stop an debris getting past them and into the carbs, I was thinking that the pods would give plenty of air anyway so sealing the gap s would affect it - what are your thoughts?

I'll go take some photos and post back so that the above makes sense!

[DF217]

Photos

Here are a few photos to show how the original airbox rubbers have been used with the pods so that the outside pods fit on an angle and fit the frame/covers.

This was done before I got the bike and they seem to have a slight leak round the join so I was going to seal this so that no debris gets through to the carbs.