1994 KDX220 SR conversion

[AndrewB]

Ok folks - could use a little help with jetting...
1994 220sr from Japan (been told it's probably a "B" model. Am reconditioning and derestricting.
Got 33mm Sudco Keihin pwk off ebay. Comes with 52 pilot, 165 main and CGL needle - no idea what size needle jet is.
Have changed the airbox to 220 standard (the sr is smaller) - modified (ported) the reed block to match the profile of the new (standard) carb boot.
Tried standard jetting (42 pilot, 145 main R1173 needle - clip 3) - seems WAY too lean! Plug white
Then 42 Pilot 165 main, CGL needle - clip 3 - not bad at full throttle, but very rich everywhere else
The 42 pilot, 165 main, R1173 - clip 3 - smooth but flat everywhere
Now 42 Pilot, 145 Main, CGL needle - clip 4 - pulls well, but plug still showing bit lean at full throttle

Any suggestions? looks like I'm going to need more jets - was thinking 40 pilot, 155 main and CGL -clip 2 might be a good start...

Rest of the bike is pretty much stock - have replated cylinder and done new bottom end (bike has done 27,00km). Stock expansion chamber, but the last owner told be it's been gutted. FMF muffler, but don't know which one - whole pipe is a bit leaky. Stock reeds (new) and snorkel still in (to keep the water out!)

Any help / suggestions appreciated...

[KDXGarage]

Can you post a VIN / frame number and engine number? Thanks!

[AndrewB]

Hi

Frame is DX220B-001502

Engine is DX220AE-001692

[KDXGarage]

That is correct, 1994 KDX220-B1.

PC = Parts Catalog
OM = Owner's Manual
SM = Service Manual

[AndrewB]

Thanks Jason

Rechecked the KIPS operation after reading some of the posts here - sure enough, sub-valve shafts binding after the cylinder plating. Honed out with some emery cloth and rebuilt - that's made a difference! A whole top end that wasn't there before :-)

Can really feel the valves opening - Is it usual to get a power surge as the valves open, or should it be a smooth transition?

[KDXGarage]

Good job on figuring out that the power valves were sticking! I had read of that before. A guy I helped years ago determined his to be that way.

It's hard to contain an animal like the KDX. JUST KIDDING. It can produce a bit of a surge.

[AndrewB]

Aye, it was a random purchase - just browsing tradme (the New Zealand ebay), and there she was for $1,800 (NZ)! - even after spending about the same on restoration and derestricting, I pretty happy

How often does that KIPS need cleaning out, by the way?

[KDXGarage]

It depends on how cleanly your bike is jetted and how often the engine is run. Over time, unburned oil can build up as carbon on the teeth and shear them off.