Posts
18
Joined
7/29/2024
Location
Cassville, MO
US
Does this scraping on the piston look like it would be causing a bunch of extra smoke I haven’t checked the crank seals but I was wondering about the piston first also would it be wise to just get a new piston with how this looks? Btw this is exhaust side the other side still looks great. Also it’s a vertex piston
Tough to tell from the coating color and such, but it looks like you’re getting blowby and like the skirt is shiny, meaning the next step (if not already) is piston slap. Let that go long enough and it’ll break the skirt.
What bike, what’s the cylinder look like, what oil/fuel, etc?
It’s a 2003 Honda cr250r. Cylinder is barely starting to get little scratch lines mostly on exhaust side but it’s not bad at all hardly even noticeable. I run 32 to 1 usually but to see if it would help I tried 40 to 1 but it still smoked a lot!
Walmart oil
Do a leak down test, it's likely to be the clutch side crank seal, but the last generation CR250's were prone to leaking between the crankcases under the intake...
M6 bolts holding the cases together were increased to M7 in 2005 to reduce leakage.
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Gotcha I’ll try it. Do you guys think I should get a new piston with how this one looks?
Can’t tell just by looking. There are wear limits in the manual. If you can’t measure it, go by number of hours on it.
That won't make it smoke but your piston is on it's last legs. Only 2 things will make it smoke. Rich jetting and a transmission side crank seal or center case leak that is sucking oil.
So I’m pretty certain that it’s not my crank seal cause I haven’t lost like any oil. Could the power valve have anything to do with it? My jetting is all good besides the pilot jet it’s supposed to be 30 but it’s 32.5 could that make a big difference? I have notice after I go through the gears and into the power band it starts to smoke less but still smokes a decent amount. Also it fells kinda boggy ish
If it smokes more after idling for a minute then yes it may be rich and loading up. You can mess with the air screw to see if that helps but going down on the pilot should also tell you if you are going in the right direction. If it is too rich on bottom a leaner pilot is ultimately how you will have to fix the loading up. Just watch as you lean out the pilot that it doesn't get too lean mid to top. A rich pilot can mask a lean needle or main because the bike is running off that extra fuel that loads up when on the pilot jet.
Post a reply to: Help I need to see if my piston is causing excessive smoke