Engine Problems With Honda CBR250.

[Goldmember]

I have a question. I have just taken my exhaust off and their is no carbon bulid up, But the other 3 exhaust ports have it. The valves a white not black and it seems to be damp in the port maybe petrol. I have checked for spark and i have got, I have also checked there is fuel getting into the carbies and into the air flow through the verturi buy the fuel nozzel. So am am maybe thing it might be a combustion problem but i not to sure. So does anyone know what i might have a problem with. I have done a basic course in Mechanics at midland tafe so i do have some basic knowledge in the area .
I do Have the owners manual.

Cheers
Simon

[Maxo]

what is the problem again?

running on 3 cylinders?

[Satan1]

Maybe you lost the rings from one piston and don't have compression on that cylinder?

[Goldmember]

I don't know if i have compression in the cyclinder and yes only 3 are working out of the 4.

[Satan1]

Check the most obvious first.

Spark and compression, It's damp in the port so I wager it is getting fuel.

[Goldmember]

Yes it is getting fuel and there is a spark. so if worse comes to worse I will strip down the engine to see what the problem is.

[darkfibre]

Are you loosing coolant?
You can have a lack of carbon build up if the head gasket is leaking coolant into the cylinder.

[Goldmember]

How would i check if i have coolant leaking into the cylinder?.

[Desmo]

Haven't we been through this already and given you the answers?

[Goldmember]

I have asked you people questions before but that was about my spark plugs.

[Desmo]

And you don't think that it might be slightly related?

[Goldmember]

I don't know that is why i am asking people on here Desmogod.

[Desmo]

OK simon27, I'm glad we have cleared that up, you evidently have issues putting 1+1 together, so I'll spell it out for you.
Your engine is fucked.
You need an engine rebuild.
The ring in the sump was probably a pretty decent giveaway and your soggy plug, it only firing on 3 cylinders are all possibly related to the aforementioned plug. (Although I could be wrong).
Your white valves are burnt and also fucked.
Let me hazard a guess and say that the soggy plug is *gasp* from the cylinder that isn't firing?

[Goldmember]

Thanks for that Desmogod so it might be worse than i thought DAMMIT .

[Jamathi]

If a valve is burned then that could also be because a wrong tappet/lifter or camshaft hardening related problem, Could it not?
If so the head need to be redone?
Bottom end could well be still OK.
CBR 250 4 cil all revs 20K? and the like??