Valve clearance GS550 '78

[11csive]

My work computer doesn't have the greatest resolution, but is it possible that the one exhaust port just looks worse because its wet (maybe from all that stuff you've been spraying to get the pips loose)?

Ive never tried it on a motorcycle, but on the old cars you could clean them valves pretty quick by warming up the motor then running the motor up to a decent speed and spraying a little water in the carburetor. It doesn't take much to clean most of that carbon off the valve and piston tops.

I'm close to 100% sure that none of the rust-remover I used, ended up at the valve. I might be wrong, but I really don't think so.
The water in the carbs sounds interesting, anyone on here used it on a motorcycle?

 

[11csive]

I did some work on the bike yesterday.

Just an out-of-the-box thought here, but maybe that number 2 valve cannot close all the way because of excessive carbon build-up around the stem, preventing it from going just that little bit further into the bottom of the valve guide?

I would try scratching the carbon from the valve stem with a piece of hard wood sharpened to look like a chisel point, or something similar. Even careful use of a metal chisel should not damage the valve stem. While your wife is not around, use the vacuum cleaner to suck out the loose bits of carbon.

Just something to try before you go stripping the head.

I removed as much build-up as I could. Then had a look at the the clearance again - no difference unfortunately.

OEM Suzuki gaskets are best.

Regarding the shims, only 1E & 2E need to be touched. Either that engine is low mileage or someone cut the valves and shortened the stems.

If you can't see anything under #2E when you pull off the exhaust the next step is to pull the cams and remove the 2E bucket to see what's going on there. Key thing to look for is to make sure the valve stem sticks up above the keepers. If someone cut the valve stems too much the keepers may be sticking up too far.

So I pulled the cams, and had a look under the bucket. Stem seems to be properly placed compared to the keepers and nothing else seems off course.

For now I think that there's nothing else to do, than take the engine apart, and have a look at the valve. I'll keep you guys updated. Thank you for your help.

 

[11csive]

Another sunny day off work, another day spent on the bike

Finally had the time to pull the cylinder head, and have a look at the valve causing troubles. You guys suspected a bent valve, so question is. Is it bent? Oh yes, clearly.

Just to show you guys, I placed it on a flat surface, snapped a picture then rotated it 180 degrees staying in the same position as on the first picture, and it clearly shows.

Stem pointing left.

Rotated it 180 degrees, now pointing to the right.

Definitely needs a replacement. So question is, what do you guys recommend replacing when doing a valve replacement? What parts should I order together with a new valve? And what is the necessary steps to get the new valve to seal properly around the seat?

There's a valve replacement guide on bikecliff's site, the link seems broken however. Any help would be appreciated.

Oh and also. How is 1 valve out of 8 bent? Anything I should check on the engine (besides of course timing) that could be doing this? Or did someone working on the bike earlier mess something up?

 

[Nessism]

Hum, that's a strange one. Not sure what could cause that other than if the cam chain tensioner jammed up and the valve hit the piston.

Most likely the installation of a new valve will fix things up. I'd pull all the valves, clean them up, check straightness by chucking them in a drill motor, lap them into the seats and replace the valve stem seals. If you want to really do a bang up job find someone with a centerless valve grinding machine and have them kiss the seating surface and backside of the stem to true them up perfect like. During lapping you can verify the valve is sitting the seat properly. If everything looks good you should be ready to run.

 

[11csive]

Hum, that's a strange one. Not sure what could cause that other than if the cam chain tensioner jammed up and the valve hit the piston.

Most likely the installation of a new valve will fix things up. I'd pull all the valves, clean them up, check straightness by chucking them in a drill motor, lap them into the seats and replace the valve stem seals. If you want to really do a bang up job find someone with a centerless valve grinding machine and have them kiss the seating surface and backside of the stem to true them up perfect like. During lapping you can verify the valve is sitting the seat properly. If everything looks good you should be ready to run.

Ordered all the gaskets, the valve and so on. Waiting with anticipation Also bought some valve grinding paste and made a homemade lapping tool - only waiting for the shipment to arrive.

While I'm waiting I'm spending some time on the exhaust and carbs. Let's start with the carbs. Had a lot of fun dissassembling them for a cleaning and new o-rings + gaskets. (Or not).

2 out of 4 pilot fuel screws are broken, the other 2 bend. Don't know how to get my hands of 4 new ones besides ordering them from the us, which will cost me around 100 bucks including shipment, taxes and import fees. (I really don't like the idea of this to be honest). How is shipment for 4 needles nearly 25$ ?

Another thing. Looking to get myself a 4-1 exhaust on the bike. I measured my pipes to be 35mm, and think I read somewhere that that's the same as a gs1000 (79-80). Can anyone confirm this? Will I be able to put downpipes made for a 1000 on my 550? The reason I'm asking is that I'm able to get my hands on a 4-1 downpipe/collector for a gs1000 for a reasonable price, and then I'm able to fit whatever silencer on there that I like.

 

[Nessism]

Better check the carb body to be sure the broken tips are not stuck in the hole.

There are sources for those screws for a lot less than $100. You may want to look into the archives for more info.

 

[11csive]

Better check the carb body to be sure the broken tips are not stuck in the hole.

There are sources for those screws for a lot less than $100. You may want to look into the archives for more info.

Yeah, I'll have a look to see if they are stuck in there, thank you

I'll have another look then, only sites I could find are American, which will end up costing me big time

Anyone got a clue about the GS1000 pipes? Am I good to go?

 

[Nessism]

1000 pipes won't fit the 550 engine. The cylinder spacing is different and the engine height is taller.

 

[11csive]

1000 pipes won't fit the 550 engine. The cylinder spacing is different and the engine height is taller.

Thank you for all your help Nessism... Really appreciated. Had a feeling they wouldn't fit, but just wanted to get a clear answer.

I'll get back to you guys as soon as my spare parts arrive and I get on with the project.

 

[Nessism]

$5.95 USD each. They will fit in a US Postal Service "small flat rate box" which is $34 to Denmark. https://www.z1enterprises.com/product/SIK-1157SK

 

[11csive]

$5.95 USD each. They will fit in a US Postal Service "small flat rate box" which is $34 to Denmark. https://www.z1enterprises.com/product/SIK-1157SK

Thank you very much Nessism, but I ended up finding another solution. They are ~6$ each, ~35$ for shipment. Then there's the lovely 25% Danish tax (you pay tax for the shipment as well) aaaand another ~25$ import fee. That's almost 100$.

Anyway, found a guy selling a set of carbs for the 550. They are in okay condition and I payed him 400 dkk which is equal to about 60$

Tadaaaaa:

I obviously checked the condition of the screws when I picked it up, but just to show you guys

Just wanted to give a brief update as to what is going on. I'm still waiting for a lot of gaskets and a new exhaust valve, which finally got shipped yesterday. They had one of the gaskets I ordered on backorder, so it took quite a while to get to this point. But as of right now, it seems I'll be able to make some great progress within the next week or so, if everything goes as planned (It probably won't, but let's hope ).

I'm thinking about making a thread in the rebuild/project subforum instead, as this isn't exactly a thread about valve clearance as much anymore. But for now, this is the status of everything.