CBR250RR smoking when near redline

[matoc]

Evening ladies.

I've got a bit of a problem with the old CBR. Apparently it's blowing smoke when I have it near redline, especially when blipping down. Since I can't see the exhaust while riding I have no idea when it is happening, but I'm sure hmurphy will be around shortly to fill in the details.

As far as how the bike feels, I'm not noticing anything. It's not losing power or skipping around. So basically what do you reckon it could be? I'm having it taken in for its 6,000km service when I have the cash, but till then I'd like any ideas of what it could be.

PS: The track day I attended last Thursday was the first time it was noticed as I'm normally behind hmurphy and his r6 on 'takas rides. So for all I know it has been smoking for a while. If this is the case, is it common? A 19,000rpm is rather high after all.

Thanks in advance!

[hmurphy]

When the bike is high in revs and is being blipped down a gear, a dark black/purple smoke is spewed out the back and this happens when a gear is being revved out and then upshifted too. I followed the bike up the takas today and it smelled like oil the whole way up.

It is nearly at the 60,000km mark on the odometer and I wouldn't bet against it not ever having a proper service in its life (besides oil changes and oil filters). Basically... what is about to blow up in this old beast? She still runs great despite its smoking problem.

Solution: buy an R6

[matoc]

Solution: buy an R6

Wanna swap?

[hmurphy]

..........

Solution: buy an R6

[R6_kid]

sounds like it wants new rings

[hmurphy]

Cool thanks man. Any other advise guys? I need to know what tools I am gonna need to get ready as matoc has a tendancy to have his bike stripped in my garage every couple of weeks.

[driftn]

Hold it at the red line it should clear out

[imdying]

Not worth touching it... either rape it till it dies, or, given that you can't see it when you're riding, it seems likely that the muppet you sell it on to probably won't pick it up either :D And even if he does, you'll have his money ;)

[hmmmnz]

i would do the clearances ect, plugs and all the rest of the service type stuff, and see if that makes a difference,
failing that off with its head :D and then check the rings

[Squiggles]

How much oils left in it?

[hmurphy]

It doesn't appear to be burning through heaps of oil either. Even after a track day it didn't use excessive amounts at all.

[mark247]

It doesn't appear to be burning through heaps of oil either. Even after a track day it didn't use excessive amounts at all.

Doesnt need to burn much oil to make it smoke. Sounds like rings if its doing it when ya reving it out. If it's happening when you are gearing down into a corner it could be valve guides/seals.

[The Pastor]

yeah piston rings and or valve seals. - easy enough to do.

[slofox]

Almost certainly rings/bore wear...in the olden days it was common as dirt....

[matoc]

Thanks for all the replies! I guess I'll be paying a visit to Murphy & Sons Garage once again! I assume this stuff is easy enough to do myself?

[mark247]

Thanks for all the replies! I guess I'll be paying a visit to Murphy & Sons Garage once again! I assume this stuff is easy enough to do myself?

Well to do rings you have to take the head and barrel off, maybe take the engine out? but im not sure. It's really a job for a professional.

[imdying]

Unless you think it'll conk out before the end of your learner period, see post 8. From the descriptions, sounds like it won't.

[buckw65]

Before you start ripping things apart. You might want to try a leak down test. Much better the a compressoin test. It will give you a better idea of what is going on. Also try changing the oil, but use a good high quality oil. It is very hard for the oil control rings to scrap the oil from the cylinder walls at that velocity. Poor quality oils tend to loose their vescocity at extemes.
If the rings are sticking at all, this well cause it too. Oil change might help clean the rings a little and it doesn't cost to much. Another but more serious problem is if the bottom end is getting loose. If the rod end is loose and is throwing to much oil onto the cylinder walls the rings won't be able to control it.