ESE's works engine tuner

[Michael Moore]

Also look at the Honda ATVs and scooters, as a lot of them have oil pumps that are chain driven off of a doubled-up cam chain sprocket or a dedicated sprocket on the other side of the crankshaft.

My notes show an XR185/200 oil pump at 1.76:1 reduction (21 drive, 35 driven) is claimed to pump 4.0 L/minute at 8000 RPM, a CB100/125 is 2.4 L/M @ 10000 RPM, the horrid plunger oil pump on a CB175 twin is 3.6 L/M @ 10000. A CM250 twin has the same rotors as an XR185 but 15mm wide instead of 10mm and a 20/40 drive/driven reduction. Honda reuses a lot of the same rotor sets with various gearing changes.

cheers,
Michael

[speedpro]

An FZR250 oil pump might be used as well. Completely self contained with in/out ports and a drive shaft. They bolt to the engines just in front of the drive sprocket. The water pump piggy backs on the oil pump. Could be fitted with a simple adaptor for the oil lines and possibly electrically driven.

[TZ350]

I'll have a dig in the shed and send Rob one, I think i have a CB100 on as well.

I am not sure how I could drive it but I would be very interested in looking at one if you're happy to send it to me.

[adegnes]

Oko Powerjet nozzle too short? Doesn't seem to flow much at all on my bike...
Did you modify/lengthen it on the Beast TZ?

[TZ350]

Oko Powerjet nozzle too short? Doesn't seem to flow much at all on my bike... Did you modify/lengthen it on the Beast TZ?

No, but we did notice on the dyno that some engines (all modified Suzuki GP 125's and OKO carbs) liked having a power jet while others did not. Puzzling because the setups were pretty similar. Also even with the power jets functioning (hose connected) some motors drew fuel through them while others could not suck any fuel up worth a dam. It was pretty random so we just let the motor tell us what it liked.

[adegnes]

No, but we did notice on the dyno that some engines (all modified Suzuki GP 125's and OKO carbs) liked having a power jet while others did not. Puzzling because the setups were pretty similar. Also even with the power jets functioning (hose connected) some motors drew fuel through them while others could not suck any fuel up worth a dam. It was pretty random so we just let the motor tell us what it liked.

Puzzling indeed... Same carb used on the different bikes?
I can clearly see fuel being drawn up the hose but no spray into the venturi.
Maybe the jet is just too small, the hole is tiny.

[Frits Overmars]

Oko Powerjet nozzle too short? Doesn't seem to flow much at all on my bike...

Powerjets were originally developed for piston port induction, with the nozzle feeding in from the top of the carb bore, the idea being that at part throttle there would be no airflow across the nozzle, so no fuel flow through it. The powerjet would only come into action at full, or allmost full throttle.
Today, powerjets are used in a different way and the top-feed position has no advantages any more, while it still has the disadvantage of a slow reaction due to the long path from float bowl to nozzle exit, plus the fact that the fuel first has to be sucked all the way up to where the hose connects to the nozzle. As long as there is not enough suction to pull the fuel 'over the hill', nothing will happen at all.
If you position the nozzle lower, like on the picture below, response will be a lot better. Make sure that you view the picture in its full format; klick on it 3 times.

[adegnes]

Powerjets were originally developed for piston port induction, with the nozzle feeding in from the top of the carb bore, the idea being that at part throttle there would be no airflow across the nozzle, so no fuel flow through it. The powerjet would only come into action at full, or allmost full throttle.
Today, powerjets are used in a different way and the top-feed position has no advantages any more, while it still has the disadvantage of a slow reaction due to the long path from float bowl to nozzle exit, plus the fact that the fuel first has to be sucked all the way up to where the hose connects to the nozzle. As long as there is not enough suction to pull the fuel 'over the hill', nothing will happen at all.
If you position the nozzle lower, like on the picture below, response will be a lot better. Make sure that you view the picture in its full format; klick on it 3 times.

Thanks Frits!
I'll see if I can fab up something.

On a different subject, my Powerspark ignition is TCI, constant positive battery voltage on the coil, the negative side is switched. It's ment for 11-13v, and I'm not sure how it would react to being fed say 16v.
In the last few runs I was experiencing misfiring at high rpm, and a probable cause(I think) is that battery voltage had fallen to around 11v.

Now, could I keep the 12v battery for powering the ignition unit, but use another one of higher voltage to feed the coil? Common ground for both batteries.

[Tim Ey]

... while it still has the disadvantage of a slow reaction due to the long path from float bowl to nozzle exit, plus the fact that the fuel first has to be sucked all the way up to where the hose connects to the nozzle...

As I have just refurbished the carbs on my Aprilia RS250 (Streetbike with crapy suzuki cylinders, not such fancy stuff as quoted by Frits) I came to notice, that they got a tiny brass reduction mounted in the powerjet hose.

I came to the conclusion, that they might act as a non-return valve hence the power of the suction pulse might be powerfull enough to draw fuel through it, on the contrary they might be too small to let gravity pull it back.

Anyone got experience with those?

[Grumph]

Thanks Frits!
I'll see if I can fab up something.

On a different subject, my Powerspark ignition is TCI, constant positive battery voltage on the coil, the negative side is switched. It's ment for 11-13v, and I'm not sure how it would react to being fed say 16v.
In the last few runs I was experiencing misfiring at high rpm, and a probable cause(I think) is that battery voltage had fallen to around 11v.

Now, could I keep the 12v battery for powering the ignition unit, but use another one of higher voltage to feed the coil? Common ground for both batteries.

In theory, yes you could. But the old "keep it simple" rule should apply. If you're running out of battery voltage, get a better or bigger battery - or use a better charging regime.
I run almost evrything I build as total loss battery powered ignition and job #1 is to use an appropriate size battery for the task.

[TZ350]

I have single cylinder Drag Bikes & personally like/prefer the Air Shifter setup and feel it is much better than any of these transmissions.

I would very much like to know more, is this something I could make easily? are the parts simple, readily available?

[oldjohnno]

Thanks Frits!
I'll see if I can fab up something.

On a different subject, my Powerspark ignition is TCI, constant positive battery voltage on the coil, the negative side is switched. It's ment for 11-13v, and I'm not sure how it would react to being fed say 16v.
In the last few runs I was experiencing misfiring at high rpm, and a probable cause(I think) is that battery voltage had fallen to around 11v.

Now, could I keep the 12v battery for powering the ignition unit, but use another one of higher voltage to feed the coil? Common ground for both batteries.

Increasing the primary voltage is often used to improve the output of inductive ignitions. See http://www.iceignition.com/voltage-boosters

Inductive systems have the advantages of simplicity and ruggedness and a very long duration spark. I've successfully used systems that consisted of a Hall effect trigger, a 14.8v lipo battery and a Ford TFT module and coil. The TFT can even be triggered by points. Very cheap and reliable but the downside is they draw a lot more current than a CDI of comparable output. CDI power consumption is typically only 20% of inductive - not usually an issue in a car but can be a big deal on a bike. Theoretically the faster rise time of the CDI should also be an advantage but I've never experienced plug fouling problems with a good inductive setup.

[adegnes]

In theory, yes you could. But the old "keep it simple" rule should apply. If you're running out of battery voltage, get a better or bigger battery - or use a better charging regime.
I run almost evrything I build as total loss battery powered ignition and job #1 is to use an appropriate size battery for the task.

I am a believer in KISS too, and if running out of juice is the problem I totally agree!
The reason I was down at 11v last session was I had to use a bad battery, I'd killed the one I was using by leaving the water pump on since last weekend...
The dual battery idea was to be able to feed the coil higher voltage than the ignition unit can handle, and thereby creating more spark energy, needed or not.

Increasing the primary voltage is often used to improve the output of inductive ignitions. See http://www.iceignition.com/voltage-boosters

Inductive systems have the advantages of simplicity and ruggedness and a very long duration spark. I've successfully used systems that consisted of a Hall effect trigger, a 14.8v lipo battery and a Ford TFT module and coil. The TFT can even be triggered by points. Very cheap and reliable but the downside is they draw a lot more current than a CDI of comparable output. CDI power consumption is typically only 20% of inductive - not usually an issue in a car but can be a big deal on a bike. Theoretically the faster rise time of the CDI should also be an advantage but I've never experienced plug fouling problems with a good inductive setup.

Thanks for the link, a little pricey for me tho...
Something like a 14.8v lipo as "coil feeder" was what I had in mind!

[Grumph]

Current draw for the inductive systems i've used varies from 1 amp to around 1.8 amp for a big multi using something like a Dyna.

I like the points replacement modules like the Pertronix as a trigger.

[speedpro]

Your little 2-stroke should ideally be running a CDI. Failing that a TCI like you have. If the voltage supply sags out you have a problem.

With a Kettering system which is essentially what you have you need to look at the dwell time required by the coil to build current to maximum prior to the spark, and then a period of time after the spark required by the system before the coil primary current can be switched on again. At say 15,000rpm you have 4mS cycles. A couple of ignition coils I have been looking at lately have a 1.8mS required dwell time + a bit more with spark and after-spark. Say 2.5mS total time per cycle.
If you are dead set on supplying the coils with a separate 12V source you might be able to use something like the LS1, LS2, or LS truck motor coils. They have a built-in igniter so only require the appropriate 12V signal in to switch the major current to the coil primary. I have a couple of LS2 coils and they are a very tidy unit. A lot of the "drifters" use them in their big boost turbo engines. The truck version is supposed to provide a very mean spark but draw a bit of current.