I had sth like that with el cheapo scooter HV coil , engine just didn't wanted to rev above certain rpm.
I had sth like that with el cheapo scooter HV coil , engine just didn't wanted to rev above certain rpm.
Old tech but possibly related: when Team Bike's CB900F (16v air cooled IL4) endurance racer had trouble with the engine going flat it was determined that the OEM spark boxes/amplifiers were limiting the current to the coils which then couldn't fire the plug well at high RPM/cylinder pressures. Mistral Engineering made up some custom Lucas RITA amplifiers for them and those problems went away. These were later offered as the LR138 RITA kit, and could also be fitted to KZ1000s.
http://www.howardleesracing.co.uk/in...es/Page623.htm
cheers,
Michael
Check out my YouTube channel! - 2STROKE STUFFING -
https://www.youtube.com/2STROKESTUFFING
Two strokes & rum!
Thanks for the info!
The ignition mate should be able to pick that up if it's the case for me too. I'll film it.
http://tecmate.com/products/ignitionmate/
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Check out my YouTube channel! - 2STROKE STUFFING -
https://www.youtube.com/2STROKESTUFFING
Two strokes & rum!
My neighbours diary says I have boundary issues
Bit of fun on the ESE dyno this afternoon. Trying the lower throttle settings on Rob's EFI bike. We gave up on the autotune option as the autotune software didn't understand the rapidly escalating fuel requirements of a good 2-stroke. Today we were manually tuning using the lambda meter, initially at around 10% throttle and just looking for lean patches as revs increased. Did a couple of dyno runs as well to look at the curves. There was a bit of a dip at certain revs and even though the lambda was good we upped the fuel a bit and presto, dip filled in. Did a few full throttle runs as well which pointed to leanness through the mid-high range. Bumped the numbers up there as well to bring the lambda to something like expected. One thing we found out is that there was about .1 seconds between an engine event and the lambda changing, at 7-9,000rpm or so anyway. Very interesting power readings with the runs we did once we were more or less happy with the lambda. At 10%ish throttle the bike made 16-18hp. At 100% throttle it made a bit more. Very impressive for a cylinder with untouched ports and a disc valve that has timing suitable for a farm bike.
EFI is definitely easier to tune than a carb though there is a lot more individual little bits that can be changed like each cell in a load map and other software configurations, versus a few main & pilot jets, & needles. Having said that there really is no need to precisely alter each and every cell. You just need a range that is on the money and blend in adjoining cells.
Check out my YouTube channel! - 2STROKE STUFFING -
https://www.youtube.com/2STROKESTUFFING
Two strokes & rum!
Yes great fun and very promising results. Speedpro's help and the wide band O2 sensor has made all the difference. Still a way to go but good results look possible.
Un ported Honda NSR250 MC21 cylinder and 48mm stroke crankshaft, 110cc. 24mm carb with TPS for a throttle body.
One of the really interesting things was that at 100% throttle we got a good 26hp and on 10% throttle we got 18hp.
10% throttle gave 69% of the power available.
As measured by the TPS so throttle twist
OR is it too big a throttle body?
Brings up an interesting point though, is this typical of anything else, eg a carb? Would be interesting to know the actual air flow rates at both the 10 & 100% points.
Also in a more general question for TeeZee and the crew, does this mean that all your troubles and doubts of injector position, etc, etc were all a product of the map settings?
I have been using a 24mm Carb that I adapted a TPS to as a throttle body. It would seem that a 24mm carb is plenty big enough. The air flow rates would be interesting.
No, worrying about those things are just because EFI was new to us and we had to guess at most of it.
It seems that the real problems with EFI software for us and most people are all the options that have to be selected like "accelerator pump" on/off "auto lean" "auto enrich", there are a 100 or so options to work through, as well as things that I have not heard of before and their effects can only be guessed at. The manual does not cover a lot of them. Most have a default setting and are perfectly sensible when you finally understand them.
On this older graph from the EFI air cooled motor, the brown 22hp line is 50% throttle. 100-90-80 etc are very close together.
I was quickly able to make good power with the EFI system on the air cooled motor but drive-ability below the green line was the problem.
The thing that caught me out for a long while was an optional function called "Decal Fuel Cut" (what the F..K does that description mean???). It turns out that by default it cuts the over run fuel when the engine is cold (to stop bore wash, see, very sensible). Well a 2T at 50 deg C racing temperature seems cold to software that by default is expecting a 4T road bike head temperature of 90+ deg's.
It took me a while to recognize that little problem, all because I was determinedly looking in the wrong place, it turns out that piss poor drive-ability had nothing to do with the fueling map at all..... I guess you get that on the big jobs.![]()
Till now I thought that the main jet position or better the volume in the emulsion tube is a setup parameter and critical (I haven't changed it yet). I thought while the needle meters the fuel you have the emulsion tube filled to the bowl level, but as soon as you get in the region where the main jet meters the fuel flow, the emulsion tube gets drawn empty. Means while changing the throttle position between these regions you get an enrichment for a short time?!
All that would be upset by lowering the main jet, right?
Is it critical or do I think nonsense?
If the float jet is bigger than the fuel consumption then this shouldn't be the case.
I've had carbs that would run low on long tracks. I made a soldered on tube to extend a button jet to further down the bowl. This kind of stopped the problem but for some queer reason changed the flow rate so it made less power on the dyno despite same jet size and the straw attachment being like 5mm wide.
Flow problems were in the carb body drilings feeding the float jet so drilling the jet was pointless. My straw only delayed the starvation.
Don't you look at my accountant.
He's the only one I've got.
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