I have done extensive research on the web regarding the KDX 200 SR. I have bought a 1994 model which was imported from Japan by a company called Mitaka here in South Africa. It seems dead standard as even the exhaust is still the original (I am planning to remove the lining inside). It has 14 500km on the odometer and I bought it on 14 000km. Since then I have been running very high quality synthetic 2-stroke oil called TTS.
Since I bought the bike about 11 months ago, it won’t go into the power-band without double-clutching it up to 3 times or so. Even should it go into the power-band, the response and power is very disappointing. The low and mid range is fine but as soon as I expect the top end power-band to kick in, it puts its head between its legs and stutters.
This let me to the internet as I have little experience regarding the KDX and service for bikes in South Africa is sub-standard and extremely expensive.
Could you please inform me which of the 5 following causes is most likely causing this symptom?
1. Jetting;
2. Combustion chamber pressure leaking into the gearbox;
3. Broken and/or carbon of the KIPS;
4. Standard SR exhaust being restrictive; or
5. Deteriorating coil or CDI.
Regarding jetting (1):
I did not realise that the SR was fitted with a JE 28mm carburettor whereas the R models are fitted with the PWK 35mm. I followed the instructions step by step on the JustKDX site according to Canadian Daves’ instructions and only realised after reading Craig Erasmus’ (
www.copperleife.com/craig/bikes/kdx) article on the SR that it has a different carburettor. Could I still set up the carburettor based on the specifications for the PWK?
· When I opened the carburettor I found that the needle was in the second from the top position and left it there;
· The float was slightly off and was adjusted to 16mm and parallel to the base of the carburettor;
· The pilot jet is a 45 and seems to be the correct jet as per the correction factor table supplied on the web and the riding conditions given below;
· The main jet is a 122 and according to the table should be a 148 according to the following conditions:
o Average of 82 degree F;
o 3 700 feet above sea level.
I ordered the 148 jet but will take 4 weeks to come from Japan. I suspect that the 122 was put in as some sort of a restriction/governor in the dense traffic conditions of Japan as well as for fuel efficiency.
Combustion chamber pressure leaking into the gearbox (2):
I could not find any evidence of this as the gearbox oil is as clean as when I serviced it about 300km back. There is no significant leakage of the gearbox. The only tell tale is the overflow pipe in the air box which lubricated the filter to its maximum. I did clean the filter thoroughly when I realised this. Is it normal for the overflow to drip on the filter constantly or should it only happen when the gearbox is too full?
Broken and/or carbon of the KIPS (3):
I have no clue and don’t think that the engine has ever been opened. I do not have the expertise to do this myself and will have to take the bike in for verification and repairs should this be the cause.
Standard SR exhaust being restrictive (4):
I am planning to remove the lining myself if the 148 jet does not make a significant difference.
Deteriorating coil or CDI (5):
According to Eric Gorr, a deteriorating coil would let the bike misfire at high revs. This is what the bike is doing. Initially it would run better after it was warmed up but now a day the symptom remains even if it is warmed up.
Lastly:
Does the air-screw of the PE 28mm have an o-ring and if so, what will the effect on performance be if it has been lost?