Do the cylinders of an 81 Suzuki GS850G have steel sleeves inside of them?

[Jim C]

I look at the fiche and some pics of cylinders on eBay and it looks like there are metal sleeves that extend down from the cooling fins into the crankcase. Are these steel sleeves and can they crack?

My problem is the bike bogs down when giving it throttle. Thinking it was the carbs I rebuilt them. Nope, not it.

Noticed the headgasket had very very slight leak where it meets the cylinder. Spray carb cleaner on that area bike ran great. Filled that area with high heat exhaust sealant (just to see). Motor still bogged. That's not it.

Sprayed carb cleaner on cylinder #2 (close to cam chain, between #2 & #3 cylinders) below intakes and head gasket, bike ran great.

This is what leads me to believe it's a cracked cylinder, but if it has a steel sleeve inside, how could the cleaner get through to the combustion chamber?

Cracked head maybe? But we didn't spray the heads.

What do you guys think?

 

[bikinkawboy]

I've never had one apart, but I expect it's like nearly all other multi cylinder Japanese 4 strokes and has cast iron sleeves (not steel). Cast iron is microscopically porous, retains tiny amounts of oil and therefore wears better than steel. Steel has been used for dry sleeves (Ford tractors in the 50's and '60s), but they are paper thin and difficult to work with.

To ansewr your question, sleeves can crack, but it's very rare and I'm sure there are plenty of experienced mechanics out there that have never seen one before.

As far as a crack or leaking head gasket, the combustion pressure is going to be going out and not in as your carb cleaner experiment would lead you to believe.

Were it me, the first thing I'd do is pull all four spark plugs for a visual inspection. White to tan is normal, black and sooty is too rich, black and oily is oil and a snow white, blistered look is too lean. I'd look at #2 especially to see if it appears to be running too lean, indicating an intake (air) leak around the rubber tube connecting the carb to the cylinderhead. Also look to make sure the rubber plug, cap or screw used to sync the carbs isn't missing or cracked and sucking air.

You didn't say whether it runs better at higher rpms and worse at idle or lower rpms, but if so, I believe your bike has a vacuum operated petcock and the vacuum hose to operate the petcock usually connected to #2 carb. If the diaphram inside the petcock is leaking, you'll suck raw fuel into cylinder #2 under high vacuum conditions (like idle) but much less so under wide open throttle. If that cylinder seems to be running too lean, check and make sure the vacuum hose isn't leaking. Try pinching the hose shut, putting the petcock on PRI and see if anything happens.

As far as a cracked head, that's highly unlikely. Most heads that do crack do appear do so between the two valves, which causes low speed rough running or partial missing. Good luck and if you need more info, holler.