Crofter985'S KLX650C supermoto build

[Crofter985]

Today I have not stripped down to take out the slow jet or idle jet. My focus (after I got my real work done) was to prepare the dyno for the turbo bike, so I mounted the cooling fan on the dyno and wired it up.


With the bike on the dyno I ran it up again to see what the AFR was like through the range of operations.
The bike is really lean on idle, but once it's on a steady throttle at about 2-3000rpm it's ok 13-14:1 AFR.
Under acceleration (loaded) it's way rich sometimes off the scale 10:1 or more so now I have a bit more info to go on.
I can have a think about the next move.
I also plugged in the ignitech ignition and ran the bike with that too. Without the boost it runs just like a standard ignition. It performed well, with the ignition being very sensitive to IAP (pressure) so I will leave the new ignition hooked up now.


So lots to do.
One more thing, the boost I was seeing yesterday, I think was too much too soon, it looks just now like that turbo is too small. It just another thing to look for as I tune this thing up. The good thing is I have a exhaust pressure sensor, so far I have not seen more than 1:1 pressure difference (inlet to exhaust) so that is good but there is a lot of things to look at yet.
More later (again)

[Crofter985]

Ok on reflection, it's running a 50 idle jet and a 180 main so it looks like I have to up the idle and down the main. You with me?

[Crofter985]

Stripped the bike down to get the carb out.
Pulled the jets out put a 175 main in and then looked at the pilot jet. It's a 50 so I started putting drills through it till I found one that could not go through. I have a 48 and a 40, tried the drills in the 48 and I got a bigger one through there.??? So the 50 has got varnish in it. I cleaned this out the other day so obviously not well enough. It's clean now anyway.
Put the carb back on and ready for a run.
I also swapped the cheapo boost gauge for a glycerin filled one, turns out, a good call.

The bike would not run. So I pulled the pipe to the carb off, the one that pressurises the float bowl. It runs with that off. Still not running with turbo pipe connected. The inlet between the carb and the head still seems to have some vac even when the throttle is opened. At idle it's -0.4bar and with a bit of throttle opening it drops to -0.2, I thought it would be 0bar, but I guess there has to be negative pressure to have flow? That's what flow is isn't it? So it is a surprising result to me. One I would not have picked up with my cheap boost gauge.
This is a kinda cool picture, and it also tells a bit more about the things that's going on

It's vaporised fuel, sometimes although the bike when running is lean, if it does not start it just floods so fast, causing this fuel vapour to roll out the exhaust.
Right I've been thinking about this for a hour or so. The carb float bowl should probably not see a vac signal at all, which the new boost gauge is showing it is getting, even though that one way valve is there there could be a bit of vac getting past.

Thinking back to how it would be if not turboed the float bowl would just see normal atmospheric pressure so I know that can't work with the turbo, it's got to see boost, so I think next to try is pipe the float bowl to the plenum.
And also the FPR could also be needing to be fed from there too.
So next step a bit of re- piping and testing.

[Sandblaster]

Ok on reflection, it's running a 50 idle jet and a 180 main so it looks like I have to up the idle and down the main. You with me?

Yep... I follow you.
Was doing the Outlaw Karts last night and was preoccupied...
I need to get caught up...

[Sandblaster]

I'm digesting what I just read....
This may be the reason that others had success by building a box around the carb.
On the surface, it seems easier..
However, I think you may be on to something.
I know many have tried and failed to do what you are attempting.
So, if you manage to do it, that will be a first that I am aware of and a big red star on your shirt
I can't wait to see the results..

[Crofter985]

Going to have another go in the morning.

[Crofter985]

I swapped the float bowl feed to the plenum and fitted the 48 slow jet and the 175 main. It started with the turbo all piped up and making a little boost I did have the waste gate disconnected to begin with to limit boost. It was lean as the revs raised so I tried it with the waste gate connected and it made 5psi but really lean there.
So I put a bigger main in and as I was putting the carb back in I tried on the fuel pump, the fuel was pissing up past the float valve. I really will have to sort that but it's a proper fuel pump valve. I'll phone the guy I got it from tomorrow. Then I refitted the carb and I had forgotten to charge the battery. Oh well, another day........

[Sandblaster]

At least you made some progress...
That is always good to see

[Crofter985]

It was pulling quite hard on the roller when on boost. That was fun.

[Sandblaster]

I bet it was fun.
I wish I was independently wealthy so I could fly around the world and see all the projects in person... Just because