Project X

[garry55]

Impressed..................

[madforitkev]

I've been looking at the injector positions.

The X's marks the points where ideally I would put injectors so that they fire right up the middle of each cylinder.

This would angle my injectors up at about 45 degrees and although they would be squirting towards the inlets, as I have reed valves I dont see a problem.

Problem is the middle cylinder, X cant be in that place because of the water jacket, so it will be slightly to one side. The little red circles mark the injector positions

Good news is the case looks thick enough to take a screw in, O ringed boss (not much room for welding one).

This means the fuel rail (which will obviously have to be custom should sit between the exhausts and the casing. Maybe!!

EDIT. Or, crazy thought? The oil feed SRIS valve positions (green circles) could be used as an inject point and I could make new SRIS ports which might be neater. One SRIS feed is a bit under a crank lobe though......

[madforitkev]

SRIS ideal wont work....Duh! that's the return point.

Also on that side of the engine (exhaust) I am worried about raw fuel wash over the bearings if I squirt up past the con rod base.

So new plan......
To help with the oil mixing I am going to inject at the back of the crank chamber near the inlets and again straight up. It will mean loosing some casing ribs and some tricky welding but I think its dooable.

The yellow circles mark the spots.

Hopefully the raw fuel wash will be minimized

[madforitkev]

I am bit worried about the SRIS and its ability to oil the barrels given that I will not be adding fuel to (scavenged) oil at the inlets.

The SRIS system has 2 oiling methods. The direct feed from the pump is fed direct to the crank bearings and small ends. The remaining oil that doesn't stick falls into the casing and is pushed out via one way valves to appear again in the inlet ports. This then mixes with the fuel and lines the cylinder walls. So the second part if my concern but I think there will be enough petrol wash to pick up the inlet oil and spread it around. I guess the temperature gauge and the blue smoke (or lack there of) will tell me!!

[teazer]

The injection system goes to the inlet side of the crankcase. What you are looking at are the SRIS - Suzuki recycling system that takes surplus oil from one crankcase and moves it to another cylinder to even out the smoke.

It's an interesting idea and can be removed and blanked off with zero side effects unless one check valve has a nasty leak and in that case you would see more smoke form that matching exhaust pipe.

I block off the SRIS system on my motors. We don't need no leaky valves with melted plastic filters anyway.

Transfer ports are probably a better place to insert the injectors, but a lot more work.

[madforitkev]

Teazer,

If I put the injectors where the little yellow circles (as you said inlet side of the crankcase), then it should squirt nicely up under the piston, which may help cooling as well The risk there is contaminating the injectors.

My worry is that the SRIS return oil that oils the barrels through the inlet port (little pipe in the bottom), now wont have any fuel mixing with it from the what the the carbs. The oil will probably kinda dribble in and that might not be enough to oil the barrels. The same is true if I go in the transfers.

[Alan H]

So what could possibly go wrong..........

[madforitkev]

I am trying to avoid premix but might not have a choice......

Anyways, this weekends task is firing up the DIY ECU (will post later as long as its not a disaster!!).

Metalworks all done, PCB built and programmed. Ignition trigger module wired and working, crank sensor working.....just gotta join it all up now and see if kidding Speeduino it is a 6 cylinder 4 stroke will work. Looking on the scope it will but someone has to be first I guess.....

EDIT: Well not a great start. Lots of misfires and no real action. Either I have my trigger wheel setting off (which I doubt because I must have measured it 10 times!) or my spark table is off.

The stock bike runs 24 deg BTDC -/+ 2 deg. Because of the rune I upped that to 30 deg but that may be too much?

I've got spark everywhere and I know the carbs are good.

I will try changing the spark table timing back to stock first and see if that makes a difference......

[teazer]

Just blank off the SRIS system. It isn't necessary. No worries about oil being too thick. Besides, injection oil is quite low viscosity and should have no trouble moving through the SRIS lines if you choose to leave them on.

Not sure about firing clean fuel up at the little end bearings though. That sounds a bit sus. But, it could cool the pistons and that would also cause more of the fuel droplets to turn to vapor which would aid combustion, so it's a toss up as to whether that's good or bad - on balance.

DO you have enough cycle time with the intake port open to just fire them down the inlets?

[madforitkev]

I am going to try the injectors on the throttle bodies first, just to see how it compares to carbs. Then the oiling can stay as is.

You are right, neat fuel up the small ends is a concern but with my proposed position, most of the cycle doesn't block the injector so it will get some oil at least (as the bearings are fed from the pump directly, they should stay pretty lubed?). Also the other worry is the lack of fuel/oil mix coming in the inlet to oil the barrels if I inject straight up from the crank.

So concerns for crank injection are;

No barrel oil from the inlets feed (as no fuel injected there)
Small end may get too much raw fuel wash
Injectors although not right in the base of the casing (when oil collects) may get dirty quickly