Gs 550 rebuild

[straycat]

Hello.

I started this back in 08 but when I recently rejoined the old posts had gone ,so I'll start again.

My 1980 GS 550ET. Bought from ebay with "no know faults" and "used daily"................a joke,but that's another story.

Looks ok I know,but it wasn't.


Steering had been moved out of twisted and made it feel very unstable, but after undoing the forks and realigning it was straightened out .

Engine leaked from head gasket and bike would not rev out or idle. Cleaned tank and float bowls and used compressed air on carbs which improved things a lot. ................then it started to smoke a lot .

I decided to have a look at the head and check the bores -

Broken rings on no.3 cylinder. Unusually the barrels started to lift off with the head which makes me think it may have been split already.
Deep scoring to the barrel, beyond a rebore which would be really expensive anyway,so back to ebay!

I found a set of low mileage barrels and pistons off a 550 ltd for a good price. The guy said the bike had only 17000 on the clock which looks likely as the bores were perfect.


New barrels / pistons in place

Cylinder head after skimming (valves removed,ground in with new oil seals and 2 insert threads for exhaust studs)

coming together (Halfords high temp silver paint)

I took the bottom sump plate off cleaned the filter and recovered all the missing ring bits with a small magnet.

I'm going to look for the rest of my pictures
to be continued

 

[Nessism]

Nice work! I followed the same path rebuilding three different GS engines - replace worn/damaged parts with low mileage pieces off ebay. It's much cheaper that way.

Not sure if you are familiar but please be careful using non-Suzuki branded gaskets. I used an Athena kit on a GS1000 rebuild and the base gasket failed very quickly.

Good luck and looking forward to more pictures.

 

[straycat]

I thought the base gasket had failed on this but it turns out to be the cam chain tensioner .

 

[straycat]

Some more :

Preparing the barrels

Replacement pistons cleaned and fitted

putting it back together - s/hand Moted system

Finished for now - that was 2008

2009 - S/hand shocks fitted to replace worn originals.
2010 - 150 miles only as GSX750W arrives !

still has poor idle

I've returned to it's faults recently - report to follow . Hope this isn't too boring !

sc

 

[straycat]

I've recently been trying to sort out the poor idle problems -

Replaced intake o rings .Rubbers are still flexible.
Checked carbs for dirt
sealed up airbox
balanced carbs
experimented with pilot screws - I'm unsure if 3 1/2 turns is correct.

It certainly idles better, but I now have a bit of "stumbling" when I open her up after hard use.
It will pull without a hiccup from about 1500 rpm in top, but occationally it will hesitate at between 3 and 4 K after throttle has been closed then reopened. I have set the carbs for standard

Jets and needle clip are as standard
Checked float height and found 1&4 to be correct at 22.4 ,but 2&3 were about 2mm lower (higher fuel level). set them all to correct.

Annoying as it wasn't doing this before - have I highlighted another problem by sealing air leaks ?


sc uk

 

[straycat]

Decided to do a complete carb rebuild :

1st day on the road 2011 - not great . Accidentally ran out of petrol on way back from MOT. Think I've sucked everything from the bottom of tank

carbs are off AGAIN

my home made dowel with handle

some serious dirt /rust

stripped ready for cleaning

Cleaning /soaking now done.
I've just got to blow out with compressed air at work and wait for o rings to arrive from Robert Barr's excellent site,then I can start rebuilding.

Petrol tank cleaned until no more rust coming out. Petcock filter cleaned.

sc uk

 

[Nessism]

You better derust the tank in some way. There are lots of possible materials you can use including vinegar, evaporust (available in US anyway), phosphoric acid, etc. You need to kill the rust or it will continue in some way.

 

[ptexotik]

what a great looking lil' bike!!! I think I may have to look into one of these.
cheers

 

[hampshirehog]

The best way I've found to de-rust your tank, using materials available in the UK, is vinegar. Asda is the cheapest place - buy out their entire stock of small bottles of basics vinegar (12p a bottle I think) - cheaper than buying it by the gallon. And, just for devilment, tell the girl on the checkout, when she asks you why you're buying 48 bottles (or however many it is), that you are using it as fuel for your Mars rocket / going to poison the reservoir / your 128 year old wife bathes in it to stay looking 28.

 

[straycat]

Thanks , I'll go to asda tomorrow.
How long should I leave vinegar in ?

sc uk

 

[hampshirehog]

Thanks , I'll go to asda tomorrow.
How long should I leave vinegar in ?

sc uk

Hit and miss I'm afraid - depends how much rust you have in the tank (and a lot of it you can's see). Plus it depends on the air temperature (faster reaction when it's warm).

Real ballpark I'd say 24 hours. Don't forget you'll have to remove the tap / fuel gauge sender and block the holes off. There are some good threads with pictures on here on how to do this. I use WD40 to prevent the flash rusting