Cylinder wall
- Thread starter robbie
- Start date
You should ALWAYS have the cylinder honed if you're doing a rebuild. As for the nick, unless there is some part of it that sticks into the cylinder and the rings might get caught on it, then it's not an issue.
That nick is bad news. You have to finish the job buy "Chamfering" the ports...ALL of the ports!
You will,... without question, snag a ring the way it is.
Please don't half ass the job only to biotch about it when it blows up, because it wasn't done properly the first time around.
Is the piston properly fitted to the bore? .0015 for cast piston and .0025 for forged?
Let us know what the bore measures, and the piston to cylinder clearance.
You will,... without question, snag a ring the way it is.
Please don't half ass the job only to biotch about it when it blows up, because it wasn't done properly the first time around.
Is the piston properly fitted to the bore? .0015 for cast piston and .0025 for forged?
Let us know what the bore measures, and the piston to cylinder clearance.
A properly fitted piston, and proper honing, along with port chamfering is a "Complete Package".
Remember... the piston is what moves your ride when your on it. Don't half ass it.
Remember... the piston is what moves your ride when your on it. Don't half ass it.
Obviously you have to do either a hone or a bore when rebuilding but I was just trying to ask should I not worry about that or should I deffinatley bore cause I don't want to waste money. Excuse you for saying I'm Going to "biotch" this is my second post on this forum and I will not be back cause of bad attitudes like yours when I'm just asking for a little help ...thanks for nothing
Robbie,... Lighten up......Your reading me wrong. Pay attention... I am helping.
I never said you were bitching, you said that.
Its just that we (lots of folks on this site) have seen so many folks, so many times, go and half ass / oakey-fi
a top end rebuild, only to have it blow up after a short duration of use, all because they had the time to do a top end twice, or perhaps THREE times, but couldn't find the time to do it correctly the first time. There are knowledgeable people that will point you in the right direction...for free. All you have to do is listen.
This is just as important as doing a leak down test.
What size piston are you on now?
What is the bore diameter?
What is the piston diameter at the skirt?
The sooner you let me/us know the answers to the questions, the sooner you can be riding without wasting YOUR money.
Chamfering will cure that nick. You'll be chamfering after the hone, or bore job that takes it to the next over-size piston anyway. By looking at the photo again, that cylinder caught a ring in the exhaust port on both the top and bottom. Looks like the boost port (the one above the two intake windows) snagged a ring also.
Let us know.
I never said you were bitching, you said that.
Its just that we (lots of folks on this site) have seen so many folks, so many times, go and half ass / oakey-fi
a top end rebuild, only to have it blow up after a short duration of use, all because they had the time to do a top end twice, or perhaps THREE times, but couldn't find the time to do it correctly the first time. There are knowledgeable people that will point you in the right direction...for free. All you have to do is listen.
This is just as important as doing a leak down test.
What size piston are you on now?
What is the bore diameter?
What is the piston diameter at the skirt?
The sooner you let me/us know the answers to the questions, the sooner you can be riding without wasting YOUR money.
Chamfering will cure that nick. You'll be chamfering after the hone, or bore job that takes it to the next over-size piston anyway. By looking at the photo again, that cylinder caught a ring in the exhaust port on both the top and bottom. Looks like the boost port (the one above the two intake windows) snagged a ring also.
Let us know.
Not only has a ring snagged some ports but has been suffering some heat stress especially around the area of the exhaust port.
I looks very much like there was a lean mix happening, could you post up a pic of the piston.
Joe is correct in saying that the ports must be chamfered and chamfering will clean up that nick.
I looks very much like there was a lean mix happening, could you post up a pic of the piston.
Joe is correct in saying that the ports must be chamfered and chamfering will clean up that nick.
Ok it's mods are kn airfilter ported and polished 3mm stroker and a dg pipe and the guy who helped me with it cause I'm only 15 and had no clue how these worked put a 240 main jet in it which was way to lean . More pics , piston has score marks and btw it never blew up but once I started researching jetting etc and realized the guy put a 240 jet in it I new I had to rebuild , it had new rings in it and previously had a hotrods crank in it before I put the stroker In it
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I would bore it to 66.75 with new wiseco piston and have them ports chamfered, looks like who ever bored it last never rechamfered the ports, agood machine shop would know the need chamfered an its uusually included in them boring it.
FYI your bore is currently 66.50 which is.020 over stock that cylinderhas plenty of life left in it if you get the issues ccorrected now.
FYI your bore is currently 66.50 which is.020 over stock that cylinderhas plenty of life left in it if you get the issues ccorrected now.
Robbie, I see that you have been running a wiseco piston. I can see that the piston started galling do to lack of lubrication, or that wiseco started to do its famous uneven heating / four corner seizure to do no warm up time. When you get it repaired, be sure to warm up your ride before you ride. Especially with a forged piston.
The piston shows very little evidence if any of detonation due to the #240 jet.
It does however show signs of uneven heating from a hurried ride.
Forged pistons must be carefully warmed up to operating temperature.
You should not just start up and ride with a forged piston.
Cast pistons are a little more forgiving as they heat up more evenly.
A good rule of thumb when warming up an engine is to start the engine, walk round and check the tyres, blip the throttle a few times.
Put on your helmet, and do another blip.
Fasten the helmet, and another blip.
Put on your gloves and blip.
Put a squirt of lube on the chain, and another blip.
I think you can see what I am getting at, you should be doing things before you ride, just use the warm up time to do them.
You get to ride just as quickly without the fear of seizing a piston.
It does however show signs of uneven heating from a hurried ride.
Forged pistons must be carefully warmed up to operating temperature.
You should not just start up and ride with a forged piston.
Cast pistons are a little more forgiving as they heat up more evenly.
A good rule of thumb when warming up an engine is to start the engine, walk round and check the tyres, blip the throttle a few times.
Put on your helmet, and do another blip.
Fasten the helmet, and another blip.
Put on your gloves and blip.
Put a squirt of lube on the chain, and another blip.
I think you can see what I am getting at, you should be doing things before you ride, just use the warm up time to do them.
You get to ride just as quickly without the fear of seizing a piston.
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