The start of a 265cc Ducar cast build with full efi control, GX200 clone

[Darren]

Some more time spent in the workshop. The exhaust has been fabricated to suit the silencer and fitment to the go kart, I need to get a feel for the correct depth of the O2 sensor before I weld in the bung, the exhaust is only 34mm.
The forth bearing support has been a fair amount of work, I also had to wait for bearings etc..
Lastly the interesting part, engine electrics, the Speeduino takes either a VR or hall sensor, both have their advantages, the hall sensor keeps everything in the digital domain, it works at logic 5vdc and sends back a stable 5-0v signal, so this was my preference on this occasion.
Anyway here's the video....

 

[Darren]

Just thought I'd give an interim update of the kart's progress.
The chassis is all done, the engine internals are all in and the wiring is around 50% done.
I have calibrated the IAT and head temperature probe, the injector has been bench tested for actual cc/min at 3bar
The fuel system is complete with the fuel pump now in the tank.
The ecu is having a couple of alterations, this should be back next week
The power system is all done, I have a choice of 12 or 20volt dewalt batteries, these go through battery protectors then to a 10amp voltage regulator to output a stable 12.3v

 

[Darren]

Doesn't time fly when you're having fun
Been a while and we're finished, ECU is programmed (still requires autotune around the track) the engine has been bed in with ZDDP oil then stripped down for inspection, I have now put in the correct 56lb springs, I've also machined a stainless wire fire ring into the head.
Had trouble configuring the Shadow dash with the speeduino ecu, moved onto Real dash followed the install steps, redesigned one of the free examples and you can see the result in the video, this is a free app and it's great!

 

[adamjankowski51]

Nice build

 

[Denny]

Be nice to see them on the track being wrung out. Hope to see it!

 

[Darren]

Primary tuning will be carried out next Sunday at the unit, I can't make too much noise at my house. Then we should be on the track the Following Thursday.

 

[Darren]

Took the kart to the yard, tried to tune it and the coil stopped working within 2minutes, checked the 12v power and the ecu trigger signal, all good. Went home, purchased 2 new coils, installed the new coil-nothing! traced to a loose ground wire in a terminal strip! Now have 3 good coils.
Still went down to the track. it was a hot day, 32degrees celcius, the 390 kart had a float bowl issue which was sorted fairly quickly, then the coil gave out, traced that to the main HT lead which just fell apart due to age.
We were in the proccess of tuning mine, slowly but surely reving higher and higher till I floored it to 9900rpm (data log) and it stopped, here's the engine teardown:

 

[Denny]

I enjoy your videos. I’m surprised at the rpm you achieved.

 

[Darren]

I'm going to tune it without a clutch, I'll get someone to video the engine reving up once it's rebuilt and we're back at the unit.

 

[Whitetrashrocker]

Man that looks like a lot of work.

This EFI seems way easier.

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[ezcome-ezgo]

Light 'em up!!

 

[Denny]

I'm going to tune it without a clutch, I'll get someone to video the engine reving up once it's rebuilt and we're back at the unit.

I don’t see low you can tune it without a clutch unless it’s on a dyno. Don’t you need to load the engine to have it respond properly?

 

[Darren]

Basic tune first, just to get it running smoothly. I'm talking about start, idle, after start enrichment, transient throttle enrichment (accelerator pump). All this before I load up at the track, I can watch the Manifold Air Pressure as the engine is running through the revs, single cylinders don't play well with MAP so I'm running with Alpha-n instead of speed density, I have the ability to run two VE tables Alpha-n low revs then swap to speed density at higher revs, this is a long way down the line. I'm getting tired of pull starting, so I'm looking to build a basic hand held electric starter, couple of vids on youtube.

Man that looks like a lot of work.

This EFI seems way easier.

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That's similar to single point injection, there's a cheap efi kit on ali express , Robot Cantina tried it and highlighted all the limitations of the system. Got to admire the integration of the efi on that motorbike, it works!

 

[Darren]

Put the engine back on the kart, and found that the crank sensor had failed, probably due to the shock from the flywheel, I've purchased a Bosch sensor for greater reliability.... So stuck my mates thunderkart on a trailer towed it down to the unit and fiddled around with it to sort teething issues. Could be back to being Mr reliable

 

[Darren]

I'm still at it, learning as I go along. More machining, and electronics work.
The ecu took a bit of a bashing and some components failed, this is part one of the video, part two will be done when I take delivery of a molex crimping tool.

 

[Darren]

Almost there, here's a vid of the primary tune. We then started to concentrate on the road tune, we were too busy to video the back and forth around the roundabout, then a tweek on the ve table, then around the roundabout again........... Kart has great low end torque and driveablility, next phase will be to get on the track to tune above 7000rpm, we were hitting just over 7000rpm on the stand.