Piston ring worries

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jcpwn3r

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So I left my XS outside all winter because I'm a poor (dumb) college kid who didn't have a garage to keep his bike, and as a result the carb basically rusted shut. Just today I was able to get the carbs back into working order through liberal application of WD-40 and a hammer, and I got my bike running pretty well. I let it warm up for about a half hour and rode in circles for another half hour before I got brave and went WOT in first gear, noticed a brief loss of power, went WOT again and I released a trail of smoke the likes the world has never seen.

I hobbled into a parking lot and shut the bike off as soon as I was clear of traffic, thinking my piston rings were shot. I cranked the engine over a few more times and it didn't want to start, sounded like loss of compression. After reading up on this forum, I'm fairly certain the issue is the rings, which isn't a big deal to replace, I've rebuilt a CBR engine more times than I can count, but I'm scared about scoring on the cylinder walls. Has anyone else experienced this? How severe were the damages when you opened it up? Also how much would it cost me to bore the engine and replace the pistons?

my engine only has 5000 miles on it and was running fine before winter, I think moisture just got inside the engine and compromised the rings.

Thanks!
 
domains said:
use a old set of rings same size to clean groves after
Click to expand...

so after thinking about it, the smoke was coming out very white. i wasnt in a well lit area so im not 100% sure if it wasnt a little blue, but im fairly certain it was white. I'm a little wary of saying there's water in the engine because it ran with no smoke up until i gave it the beans.

some more info. Autozone was closed so i used a mix of royal purple 5w30 and cheap 10w40 with the intention of changing the oil again today. I was also running with the choke pulled when this happened. i checked the oil right after and it looked like chocolate milk. not sure if thats because theres gunk in the block or worse.

does this still sound like bad rings or do you think i blew a gasket too? or heaven forbid i have water in the engine.

I'd like to run the bike again so i can get a better idea of whats happening, but im scared i'll damage it. what do you think? the bike still starts, it's just more difficult now.
 
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I have the same thought as Scorpio. But I would Oil your jugs for a few days first. You know Put a few tablespoons of oil in each cyl .Use the kick start to slowly roll it over with out the plugs in a few times. Put the plugs back in and let it sit a few days. Use something like ATF or Marvel mystery oil. Something that will penetrate most sludge and carbon deposits. Before you start the engine be sure to take your plugs out and kick it fast a few times to expel most of the oil . It WILL smoke for a while when it starts but this has worked for many old farmers and auto restorers. This will usually get you going reliably for the season and you can repair or rebuild thru the off season.
 
MrStubb said:
I have the same thought as Scorpio. But I would Oil your jugs for a few days first. You know Put a few tablespoons of oil in each cyl .Use the kick start to slowly roll it over with out the plugs in a few times. Put the plugs back in and let it sit a few days. Use something like ATF or Marvel mystery oil. Something that will penetrate most sludge and carbon deposits. Before you start the engine be sure to take your plugs out and kick it fast a few times to expel most of the oil . It WILL smoke for a while when it starts but this has worked for many old farmers and auto restorers. This will usually get you going reliably for the season and you can repair or rebuild thru the off season.
Click to expand...

alright, ill squirt the cylinders and gas with some mystery oil and report back. when i flushed out the gas tank yesterday there was a lot of red colored oil so it could use some treatment anyway
 
I should have red the whole post first. I'm sorry to say you may have more issues than I thought. Chocolate oil sounds suspiciously like water. Change Your Oil and filter along with my earlier post. You might be ok if you had used a high quality oil like Royal Purple since there are some coating and rust inhibitor additives in it. But Water will cause rust and pitting to occur on unprotected surfaces. Your engine and transmission share the same oil and there are numerous small parts involved. Good luck I hope you dodged a bullet.
 
why do you think it would suddenly dump white smoke then? i ran almost an hour without any issues. i feel like if it suddenly water dumped into the engine, it was hanging out somewhere outside the engine.

edit: could the mix between royal purple and standard oil create that strange color?
 
You could have had water sitting in the low point of the tank. I'm thinking that the "red oil" you found in your tank was water and ethanol with rust in it. Your "chocolate milk oil" is a lot of water mixed in with the oil and whipped into a froth.

I'd suggest draining the gas tank fully and rinsing it a few times with fresh gas. Also change your oil and filter and use an oil that is JASO MA rated. You will also probably need to clean your carbs as they are probably also a mess. Once you have it running again ride it long enough to get the oil hot, about 20 minutes, and then change the oil and filter again.

Maybe you should consider a bike cover if you are stuck parking outside. It will do wonders to protect your bike from the elements...
 
I'll give that a shot. When I tried to get the bike running yesterday (before all the smoke), I pulled off the carb assembly and sprayed the hell out of it with a penatrating grease, let that all run out, then sprayed the hell out of it again with starter fluid and finally sprayed it with an air hose to clear out as much as I could. Is that sufficient for the carbs or do you think ill need to do it all again?

as far as the gas tank is concerned, I think I'll put in some of that mystery oil recommened above first to make sure I get more gunk out of the tank.

Also I ordered a cover on amazon a week or so ago and if I stop the small oil leak then I'll have a heated garage to store it in too. :)
 
I'm thinking a complete carb tear down and cleaning. There are hundreds of posts here describing the process or with links to write-ups. The better a job you do cleaning the carbs, the better your bike will run. :thumbsup:

Posted via Mobile
 
You didnt by any chance notice any rust inside on the metal of the gas tank?Just flushing wont remove it all.You will have to use viniger and lemon juice.That should clean up the rust inside.
 
Ok so I replaced the oil, used some mystery oil, turned it on and have a similar story. Lots of smoke once the engine is warm and I go to high RPMs. Some more info, after 5k the right cylinder cuts. Used to be both but after working the throttle for a little bit it's only the right one. The smoke isn't actually white, it's a little grey so I'm certain it's oil. Also it's spitting oil into the air box
 
It's sufficient to say that much more of my input would do more to confuse you than any thing else. But I can't agree more with Dave and Scorpio about your carbs tank and oil/water issues. As far as spitting oil into the air box that's called blow by. Usually on badly worn engines and engines with stuck ring's. This may also explain why 1 cylinder drops off above a certain rpm. In these engines where the pistons rise and fall alternately there shouldn't be too much of a pressure pulse in the crank case. 1 pistons movement would pretty much cancel the other one as they travel. If they both dropped off in mid range rpm but now only one does I'd bet you're close to getting the rings on both loosened up. Sorry if I am confusing you with all the input you've gotten so far. Keep those jugs oiled for a while and be patient. Let the oil do it's work for a few days.
 
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so do you think this is something that requires a ring replacement or should i just keep starting it up and oiling it? That's all I'm confused about right now.

I just did a compression test and both cylinders are getting good, equal compression. I pulled off the airboxes and they and the carbs are full of oil. I'm not sure if that oil is being sucked through the cylinders or through that vacuum hose connecting to the hose behind the carbs.
 
Sounds like you're well on the way to recovery. If both compression readings are well balanced and within 10% of the specifications (not sure what they are cheap manual) you should be fine. I don't think you have scored the jugs much. There could have been a small bit of surface rust in the bores that could be removed by the pistons movement. As for the oil in the intake how clogged are your air filters? I have seen this on a small engine. The crank case vent was installed on the carb side of the air filter and the filter was partially blocked. It would draw oil vapor in with the vacuum from the carb. Just a thought. By vacuum line do you mean the small one behind the carb near the head or the larger one leading from the crank case vent to the intake tubes?
 
ok, just pulled off the entire airbox assembly so the regulator hose below the carbs is open and the carbs are breathing open air. Basically every single issue I've described is fixed. I road it around and had no issues. Brought it up to 9k in neutral and both cylinders are firing fine. Also I didn't notice any oil spewing from that pressure regulator port.

why do you think this fixed some things?

edit: didn't read your previous post. clogged intake would explain a lot if I removed it an everything was running without issue. And I mean the one coming from the crank case to the intake tubes
 

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