KX Guru Racing

The subject of lubricating has been nagging at me since the outset of this project, the manual for the KLX says that 7-12psi is normal oil pressure. Not a lot for turbo oiling, not a lot of oiling for the cylinder head as well. This is the pumping set up on the bike.

The pump and rotor to the right is the main lube pump and the one to the left is the scavenge pump, as far as I can see this pump acts like a dry sump pump by controlling the oil level in the engine and storing it possibly in the gearbox? The main pump feeds from the gearbox through the little thimble shaped strainer so this would make sense. Im kinda thinking this through while I write this so I hope it all makes some sense.
So more oil, the scavenge pump is the same diameter, rotor size and shaft size as the main pump but 5mm wider, I'm asuming that will mean it can pump more. I have thought about this a lot, mostly through last summer, I was busy with other stuff and not home to work on the bike so I was mostly studying the manual and pictures of the crankcases, clutch cover and oil pumps. The idea then was also to put the bigger rotor in somehow, I was thinking along the lines of milling back into the crankcase to make a recess for the wider pump to sit in. I eventually gave up on that plan as it kept throwing so much problems up. Even lately I had a new plan, the KLX c is built without a kicker unlike the R, the space could house an oil pump? I got a zxr750 pump off eBay so I could get an idea of the physical size of that pump. That still might be do-able if all else fails. I did consider driving a gear pump off one of the cams but it's not as neat as a in crankcase solution.
So latest version, and to me the least time and effort for hopefully a good result. The bigger rotor goes in the pump (normally a 7mm rotor, now going to be a 12mm scavenge rotor) making the pump 5mm wider. The scavenge pump will still be there and is driven off the outboard end of the oil pump shaft, so the whole clutch cover will have to go out 5mm too, a second gasket and an aluminium packer plate cut out on a waterjet bed should do for that. The clutch release rod would have to be made longer, also I could put an extra steel and friction plate in the clutch, coincidentally they add up to 5mm thick, so that's two possible ways to achieve that. The oil feed to the crankshaft and the piston and bigend lubrication goes through the end of the end of the crankshaft and to there from drillings in the clutch cover so the lip seal that seals around there would have to be shifted back inboard 5mm by an adaptor turned out of aluminium I think. The drive to the oil pump and the waterpump would have to go out, possibly not all of 5mm, 4 or 3.5 might do, it will still be enough contact with the gears to drive it surely. Oh and the oil pump itself, I will make a new shaft for it, 5mm longer than the original, the gear looks to be shrunk/pressed on so that will be pressed off and pressed on the new shaft.
All this should be reversible in the event of it being a flop. But I intend to run some tests so I can say, yes it's more or damn I wasted my time on that scheme.
I got a loom with the last motor I got and enough electrics to run an engine off the bike so I'm going to set up a test engine to try it out.

Ohhhh... I like it...
I have some thoughts but really tied up.. More later...

I am still really busy but what comes to mind is the rest of the oiling system.
Will you need larger diameter passageways, galleys, oil lines, banjo bolts ect?
Larger pump width should equal more volume but with a restricted system you may up the pressure some as well...
I don't really know... Just some thought rolling around..

The pump volume will increase yes and hopefully also the pressure, I'm planning to get a load of test gauges and see what pressure I'm getting where. The passage ways will be fine as they already take enough oil for the engine already, the extra oil will mostly go to the turbo and I would like to see an increase at the head. The feed to the gearbox if anything I might restrict the flow to the gearbox as the whole pressure and flow to the gearbox goes past the output shaft seal and it can pop out with an over pressure, I learned that from reading a forum (260 pages) on advrider. If I have any unwanted pressure or flow, Although I doubt it will be much of a problem, I will bleed it off to a oil cooler.
As I write this I'm thinking back to the original oil pressure test I did, I got more than I expected, I wonder if there is some blockage or restriction to the head of the turbo motor? That would explain the pressure and the damage to the head of that motor, I will investigate that further.

Well I have not got a lot done this last month but been away at work, got a couple of weeks to go yet but took a day off on Sunday and put my new mill/drilling machine together.
Been sorting out some exhaust valves too, the standard KLX valves must be a bit soft, the clearances can close up quite quickly. So I've got a manufacturer who is willing to do a four valve order of exhaust valves 0.5mm up from standard. That should help exhaust valve temps as well if there is less restriction and they are going to be made of some fancy stainless that should be good for a few more degrees anyway.
There's still a lot of things to pull together here but hoping to get my teeth into it again soon.

I love your setup...
At some point I will have to invest as I have too many projects that need doing.
Is there a digital read out on the Mill?

No, no digital read out. I do have it on the lathe but I can add it after if I want. I had to stop somewhere.

Yeah, that's understandable...
At least you can ad one later.
It sure helps speed up the process

Yes you are right. It makes the lathe work much easier. My missus was kinda dropping hints I might be blowing too much money on this project, she is right of course, the end product is hardly going to be a sum of the parts, but hey, that's what a "special" is, special expensive. Anyhoo the 23rd is approaching and I'm home for 4 weeks. I have all the stuff I need to get this thing running, I don't mean in final spec because there might be no "final" it's looking like it will just be a rolling test bed, that's the way I like it anyway. So I'm hoping to be swinging my leg over it by the 19th of next month. We will see, watch this space.

I've never had a bike that was at final spec
I build it, ride it... modify it... ride it... modify it... ect...
I've never been able to resist the temptation...
Every bike it a journey all it's own