CR engine pics???

gthoma23 · May 1, 2008

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I have a 2003 CR250R. I bought it about 8 months ago. ran fine, but after my buddies used bike seized, i decided i should take a look at the internals. so it didn't seize, i just wanted to check it out.

I took my cylinder and piston into a few local shops and asked them what they thought. i got answers from, ur fine but u might want to put some new rings on there, to, u need to replate or sleeve ur cylinder and ur piston is toast, and everythin inbetween.

so i'm gonna leave the decision up to the forum. obviously the least amount spent would be best, but i don't know what to do!

so if u have ever had somethin like this happen, give me some feedback, i'd help me out a ton...

gthoma23 · May 1, 2008

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sorry for all the pics, i just have a feeling some1 was gonna ask what my other parts looked like. the pic of the piston is the exhaust side where the scraps on cylinder are (first post). the pics of the cylinder in this post are the other sides not shown in the first post. and then my crank and head.

_JOE_ · May 1, 2008

The exhaust bridge could relieved a bit more. Unforutunately I don't think you can do that without a replate. Don't quote me on that though, I'm sure someone will be able to confirm . Is it a stock sized bore?

whenfoxforks-ruled · May 1, 2008

Why is all the liquid in the cases? Cylinder looks good, well except for the bridge. You need to check the right crank seal. Did it smoke a lot, foul plugs? Me, I would split the cases, new bottom and top end for around 300 dollars.

gthoma23 · May 1, 2008

whenfoxforks-ruled said:
Why is all the liquid in the cases? Cylinder looks good, well except for the bridge. You need to check the right crank seal. Did it smoke a lot, foul plugs? Me, I would split the cases, new bottom and top end for around 300 dollars.

it smoked a little and burned some tranny oil, i planned on checkin the seal after i got all this put back together. how could u tell the seal was bad? i thought the fluid in the case was just old gas that hasn't burned yet. it looked blueish and that's the color or my premix.

so u think i need to replate it or just hone and new piston?

whenfoxforks-ruled · May 1, 2008

You should be so lucky. The right crank seal is shot, it pulls tranny fluid into the engine and the clutch debris builds up on the exhaust. Seizure is eminent. Cheap, check the ends of the crank for up and down play, also check all the rod specs. You may be able to just replace the seal. Smart, rebuild the engine. Either way, the cylinder exhaust bridge needs to be properly relieved, and the bore checked.

gthoma23 · May 9, 2008

_JOE_ said:
The exhaust bridge could relieved a bit more. Unforutunately I don't think you can do that without a replate. Don't quote me on that though, I'm sure someone will be able to confirm . Is it a stock sized bore?

i forgot to say it was a stock bore, 66.4mm. but it's a wiseco piston, and i was lookin on there website and saw ur pose to drill 2 little holes in the exhaust side if u got a bridge...and why yes i do. guess the guy that owned it before me didn't read that :bang:

so i'm gonna try cleanin the cylinder and see what it looks like and i'll put those pics up and then decide.

but on a different note, has any1 had Racers Toy Store do theirs? they charge $200 and include resurfacing the deck and head and chamfer & polish the ports, i don't think any1 else does that. here's their site.
http://www.racerstoystore.com/Rtsreplate.html

or is some1 else better?

_JOE_ · May 9, 2008

http://www.eric-gorr.com/

Great guy. Give him a call. Works with U.S. Chrome, who is supposed to have the thickest plating in the business.

whenfoxforks-ruled · May 9, 2008

Eric got the last 2 smokers I had cylinder issues from. If in doubt, send it to Forward Motion. The name does speak for itself. And working with US Chrome, perfect. But the bad crank seal will destroy the new engine also.

steve.emma · May 10, 2008

it smoked a little and burned some tranny oil, i planned on checkin the seal after i got all this put back together. how could u tell the seal was bad? i thought the fluid in the case was just old gas that hasn't burned yet. it looked blueish and that's the color or my premix.

definitly a good idea to replace the seal. but how do you know it was burning tranny oil? i mean unless its really consuming a lot of trany oil between changes and you measure the difference then how can you tell? it should smoke anyway, it is a cr after all.
the liquid in the cases on the crank flyweights that is shown in the pic will almost certainly be premix oil. the fuel evaporates and leaves behind oil, thats another reason 2 strokes smoke more just after they are started after having not been used in a while.
as for drilling the holes in the piston, they are there to help lube the bridge but they are not that important. the standard pistons do not have them, and if everything else on your engine is correct then it wont make any real difference.
the markings on your piston/cylinder have been caused by something else, maybe like its been pointed out a leaking crank seal etc.. if there was not enough bridge clearence then it could be the cause also, but once the clearence is set it should not change. so unless the cylinder was always faulty i doubt thats your problem.

whenfoxforks-ruled · May 10, 2008

A 2 stroke burning damn near any premix, smells good. Burning trans fluid smells like crap! Did not perform a leak down test, but had a drop in fluid level. It is possible that the cylinder is still usable. Clean it up and check the bore and exhaust bridge clearance. But I would recommend checking the crank and main bearings. At least the seals need to be replaced. I would also check the water pump impeller, bearings and seals also. You go through weak spots and have a better chance at a fresh engine. When you can get all the parts for around 300 dollars, what the heck? About the same price as a full tank of gas in your truck!

gthoma23 · May 10, 2008

steve.emma said:
definitly a good idea to replace the seal. but how do you know it was burning tranny oil? i mean unless its really consuming a lot of trany oil between changes and you measure the difference then how can you tell? it should smoke anyway, it is a cr after all.

i read in my manual that a bad seal could let in tranny oil and make it run rich. mine was running pretty rich, so i changed the oil and road i think twice. half way threw the second ride i decided to check, pulled the plug and nothin came out. so i started addin oil. i think i added around 8 ounces, and it holds like 22. so either i messed up when i added it, our my bikes burnin it cause it doesn' t have a leak.

steve.emma · May 11, 2008

i assume when you say pulled the plug to check the oil level you are talking about the level check plug on the r/h engine side? the problem with that is its not a good way to check oil level if the bike has recently been running. to work out if the bike is using oil it needs to be done more accuratly than that.
like foxforks said if it was burning tranny oil it would smoke excessively, smell bad, and probably foul plugs when slow speed riding.

gthoma23 · May 21, 2008

steve.emma said:
i assume when you say pulled the plug to check the oil level you are talking about the level check plug on the r/h engine side? the problem with that is its not a good way to check oil level if the bike has recently been running. to work out if the bike is using oil it needs to be done more accuratly than that.
like foxforks said if it was burning tranny oil it would smoke excessively, smell bad, and probably foul plugs when slow speed riding.

I measured it when it had completely cooled down both times. so even if this isn't the best way to measure it, it's gonna be off the same amount both times.

i don't know this for sure, but i'm guessing there are different degrees of a seal goin out. i think mine is goin, but not gone yet. so it burns a little, fouls plugs a little, and smokes a little. i'll just have to tear it out and see.

steve.emma · May 22, 2008

check the gearbox breather hose isint blocked as this would cause oil to be forced past a seal that was only partly bad.
the best thing to do with gearbox oil is to drain completely then add the correct amount back in, not bother with the level check plug routine.
the bike would have to be really badly smoking or fouling plugs to use the amount of tranny oil your post desrcibes.

CR engine pics???

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