ESE's works engine tuner

[F5 Dave]

My take on the powerjet being turned off is that you do actually want to lean it off at the top to heat things up. You have to be careful with a carb setup for unleaded as the powerjet will be on the larger size. If you are running Avgas and already running leaner than on unleaded, and then switch off the powerjet, things could get ugly real fast. For leaded fuel and associated jetting the powerjet needs to be smaller in comparison so a smaller amount of fuel is switched off.

Wob had suggested a PJ size for Av & I've converted the KX carb with that size to start with.

Thus experience has shown that as leaded fuel works best with a lean condition at peak power, we only need to switch a small jet just past peak - to increase the pipe temp and
thus give better overev.
In the Keihin numbering this is in mm dia and switching off a .35 is perfect.
When running unleaded, as the GP bikes have for years, the fuel likes to be rich at peak to create the best power, thus we need to switch off alot of fuel flow to increase the pipe heat quickly enough.
In this case a .65 is needed to do the job.

[TZ350]

Page 840 ...

[husaberg]

Can't remember where it was from and i was looking for something else.......

I have not seen much written about power jets. Thought I'd share what I know, and hope others can augment it. Perhaps the most succinct definition of a power jet comes from A. Graham Bell's book Two-Stroke Performance Tuning.

"The Powerjet has the effect of enriching the mixture at full, and close to full throttle, and then only when air velocity is high enough to create a vacuum of sufficient intensity to discharge fuel. It is, in effect, a load sensitive enrichment device."

Kay Nissi (sp?) at Mikuni America calls the power jet a "Band-Aid". He says it allows you to run a leaner main jet (for better part-throttle response) while maintaining a safely rich mixture at high RPMs and WOT.

The electrically-operated power jets used on later-model TZs employ a solenoid to enable and disable the flow of fuel. I have observed the power jet solenoid's behavior with my data acquisition system. Under most operating conditions the solenoid is de-energized permitting demand-based flow of fuel through the power jet. However at very high RPMs, the solenoid is energized by the CDI computer, thus *stopping* the flow of fuel. This leans the mixture increasing the temperature of the exhaust gas. Note: This behavior ensures a fail-safe mode of operation. If the solenoid fails or should become unplugged, the mixture will remain rich.

This assessment is confirmed in SAE paper 983072, Measurement of Exhaust Gas Temperatures in a High-Performance Two-Stroke Engine: "Air/fuel ratio may also be managed to influence the exhaust gas temperature. On the test engine, the carburetor was fitted with a solenoid-controlled jet. Below 11700 rpm the jet is open and additional fuel flows to the engine. Above 11700 rpm, the control system actuates the solenoid which closes the jet. This results in a leaner air/fuel ratio which increases the combustion and exhaust gas temperatures, thereby improving the exhaust tuning."

The electrical part of a power jet (the solenoid) sometimes goes bad. A bad power jet solenoid is difficult to diagnose. The engine just runs a bit rich on one cylinder. Therefore, it is a good idea to test the solenoids occasionally.

There are several ways to test the power jet solenoid. On TZs which have a battery, all you need to do is switch the bike on. The computer in the CDI box performs it's power-on self test which includes cycling the power valve servo-motor and the power jet solenoids. Using a piece of radiator hose, you can listen for two distinct "clicks" emanating from each of the solenoids. The first click is produced when the solenoid is energized -- retracting the pintel (this would stop the flow of fuel). The second click is produced when the solenoid is de-energized -- extending the pintel (allowing the flow of fuel).

If you unscrew the solenoid from the fuel-handling part of the power jet (as if you were going to replace the jet itself), you can actually see the pintel retract and extend.

On TZs that don't have an internal battery, you can perform the same test by using Yamaha's test lead (P/N 3TC-82117-00) and an external battery.

To test a power jet solenoid that is off the bike, simply apply 12 volts DC to it. (The solenoid is not polarity sensitive.) You should see the pintle retract and extend each time you apply and remove power.

Because it is next to impossible to repair the solenoid if its electrical connection comes off internally, it is prudent to zip tie the cable to the body of the power jet. This preventive maintenance provides strain relief and should keep the cable from becoming detached in a crash or due to rough handling.

Although OEM power jets invariable come fitted with an opaque hose, I prefer to run a translucent hose. (I use an alcohol resistant fuel line manufactured by Bing and sold through Aircraft Spruce and Specialty.) This allows you to verify there is fuel in the float bowl and also lets you see the fuel level.

The tech term for what Frits is describing is Superposition of the Ex pulse.
This is easily described in a sim, where a residual pressure ratio is seen sitting at the Ex port when it is opening.
The "new " pulse is added to this residual, and a very large pressure ratio exits down the duct to the header.
The larger the initial ratio, the larger the amplitude of the wave in the diffuser - this creates a deeper depression around BDC, and it is this that initiates the biggest mass flow
from the transfers.
The lower Ex timings of 190 and below create larger residual pressure ratios,over a wider band, and thus these work with a good pipe design to use "resonance" to increase band width and also peak power.
Big problem though is this whole concept is at odds with maximising blowdown to allow good peak power and more importantly, overev power.

The sim shows RGV100 making serious power with the superposition pulse going down the duct - off the scale.

Re the trombone pipe results you did sims for TeeZee.
Look carefully when you say it seems to affect the top end "more ".
At 9000 the lowest reading is 13 Hp, the highest reading is 17 Hp, thats an increase of 4 Hp, thats 31% more power in the bottom end, that then allows the thing to rev to 17,000.
Seems a not bad result.

Re the powerjet temp result you mentioned.
The effect of the solenoid powerjet is as you described - this I only discovered recently with a datalogger that I could set the sample rate of the EGT high enough to read the temps quick enough - along
with some exposed junction probes.
I was testing a RS125 on the dyno and it was making NO power past 12500, looking at the data you could see the egt drop from 640 C to 580 in around 400 rpm.
After fixing the fact some idiot had left out the rpm plug in the loom, the solenoid now switched on at 12200, and the temp stabilised at 650 past 12500 and the thing than reved out to 13500 +.
So the powerjet switching isnt making the mixture "lean"as such, it is simply maintaining the correct mixture, and thus the temp in the pipe.

I have looked into the "overangled" issue that creates a problem when using the electronic powerjet carbs.
Its worth plenty of horsepower to keep the intake dead straight, and I am building a KTM250 for a open class kart at present.
I have bored the 38 to 40.5 and mounted it on a straight rubber manifold.
This sits the carb too steep, in that the siphon hole for the powerjet circuit in the side of the bowl is only just "underwater" when sitting static.
Get some serious G forces working and this will be sucking air.
It looks easy enough to Araldite a small external tube running forward to the front of the bowl that has plenty of fuel height above it at all times.
Or maybe drill a hole thru at an angle forwards, and press a small brass tube into this to collect fuel from the front side of the bowl.
I will pic this when I have done it.

When using a simple powerjet nozzle the tip position matters in that no flow will occur until the slide is well past the exit hole, and there is sufficient airflow
to drag fuel up the feed tube above the bowl level.
With the aftermarket add ons and the ones as used by Lectron you can shorten the dump tube so that the flow will only occur at high slide openings,as well as high air flow.
These also have a built in "lag "control in that it takes time for the fuel to rise up the tube and dump out the exit into the air stream.
With a solenoid controlled setup all this is pretty much irrelevant as the flow can only occur when the solenoid is not powered up, and this
is TPS as well as rpm dependant inside the ECU program..
The carbs as used on the MX bikes has the dump tube very low in the bore as they added and subtracted fuel at low slide positions in those bikes.
For a race engine I bend the tube up to around 1/2 bore, as this is where the exit is on the Kehin SPJ carb for RS125/RS250 Honda.
And the general setting is the solenoid is powered up ie no flow below 4000 and 60% TPS and is powered up again at around 12400 to lean off the mixture and increase revon.
This causes a problem with Ignitechs that are used with only a capacitor, as at startup the solenoid is powered up, dragging all the voltage out of the ECU, so I convert the ECU output
to a 3 step truth table, and have the setting such that below 1500rpm the solenoid isnt powered.

Aha, I see. I think I got it now, Frits.
If the powerjet is positioned in the middle of the venturi or at a lower point, that will affect how much it will flow, correct?

I remember both Lectron and Mikuni aftermarket PJ kits' instructions, saying that the end tip of the pj should be around the middle of the carb.
Yet the Keihin PJ of the carbs for the mx250 models is down low! Position would also affect which fraction of the flow becomes more rich or not, or that doesn't matter??

Attachment 255006

Attachment 254941

Made an adjustable PJ out of a model aero engine carb needle jet for controlling the PJ. Now to get one of those solenoids the Husaburg posted to shut off the PJ for a bit of extra over rev.

Made some progress with the shorter inlet tract and expect to get the lower mid range back again with a bit of fiddling with the carburation.

Just a little bit more and the single exhaust port engine with the RS pipe will be very close to EngMod2T's predicted power output.

Attachment 254940 125cc rotary valve with a 24mm carb and air cooled.

Measured 31 rwhp (estimated 34 crank hp) on the dyno tonight, red line is last night before the inlet tract was shortened and the jetting/ignition adjusted.

I have ordered one of Wobblys special kitset "A" Kit Pipes for a Suzuki GP125 ..... so hopefully 1 or 2 more hp and a wider spread of power. Then there is the ATAC idea for better low end.

Nope. It is drawn by the dynamic pressure at the fuel exit points in the carburetter. And that pressure depends on the mean air flow velocity along those exits.
Air flow velocity is at its highest in the center of the narrowest part of the inlet tract, so the location of the fuel exit will make a difference. And by mean air flow I mean (air flow into the engine + backflow)/2.
You see, more than enough variables; more than enough differences between the exit points of the fuel flow through the main jet and the flow through the power jet.

Re the tiny bleed hole in the TZ powerjet tube - I always thought that this was a good idea to emulsify the fuel as it exited the dropper.
But years ago i did some wet tests on the flowbench with a VCR video camera ( pretty trick shit stuff back then ).
The Mikuni was a horror scene when played back slo mo,with huge "gobbs" of fuel exiting the main and powerjet.
We then stuck on a Lectron - wow, lovely fine mist of fuel from the back of the flat needle face - and it flowed 12% more air - size for size with a venturi 2mm smaller behind the slide.

Next is the current state of TeeZees GP125, here is the latest dyno curve digitised with 16% added to simulate crank power.
Then there is the sim with an actual RS early model pipe.
Then there is the new pipe of my design.
Of most interest is that in this case the sim is giving slightly too much crank power - but the shape and peak point are all but perfect.
I would be confident now that any change in the sim, would be reflected in reality on the dyno.
In my experience the later Dynojets like a twin roller 168 with Eddy current load control to slow the acceleration rate down ,seem to read around 5 to 10% lower
so this would put the sim and the dyno reading very close, as the shape is spot on now.

You have to be very carefull with the switch point and the run time on the dyno.
The switch point is dead critical to 100rpm,so i always set it too high initially and make sure that the dyno is loading the acceleration rate to be as close to that on track as you can.
This gives the pipe time to heat up and affect the power over the top, as it would in reality.
On a RS250 dropping the switch point from 12800 ( std) to 12400 gives easily another 800 rpm of virtually no power drop past peak.
On the track,if the rider can feel the switch point ( it feels like hooking another gear)the jet is too big,when its right it should be seamless and just keep reving out.
Leaded fuel is the opposite to unleaded, in that as leaded likes to run lean - you can only use a small powerjet and thus only switch off a small amount.
A leaded engine works best with around 35 to 38 PJ, the unleaded fuel can switch a 60, in Keihin numbering, as the crap fuel makes best power at peak when quite rich..

And something that I scraped from the net.........

""The solenoid control on TZ type powerjets really just shuts off fuel flow to the powerjets right at the top of the rev range to lean the mixture off to increase the over-rev once you are past peak power.

I don't have the solenoids plugged in currently though as I find they work well enough for my current needs with the powerjets simply responding to venturi vacuum pressure in pretty much the same way as the oem 3MA powerjets work.""

Attachment 233787Attachment 233788

And here is a picture of the carbs and what I can make out, a dyno graph without, and with the power jet solenoids shutting off (red line) and extending the over rev.

So it looks like you can use an electric power jet like a standard one and when the carburation is sorted, try switching it of by activating the solenoid at or just after peak power and see what happens with the over rev.

The FPE superkart engine that won the NZ road title at Manfield a few weeks ago makes 92 RWHp on the Dynojet 168 I use.
Still not quite as good as the RS250 setup we did that won at Laguna Superkart Worlds a couple of years ago.

The powerjet carb is controlled by the Ignitech with a combination of throttle position and rpm in a "truth table".
In general the solenoid is activated with 12V ( no fuel flowing) below 4000 rpm and 75% throttle on the TPS.
Above 75% and around 12400 rpm it is activated again to lean off the fuel curve over the top of the pipe.
Looks like you will be able to reverse the fuel exit, blocking off the hole on the throttle bore side, and take off fuel from the outside bung, thru a needle jet and into the top of the venturi next to the slide.

Recently I got myself (Ebay) a 38mm carb with Throttle PS and Electric PJ from a motor crosser.

Wobbly told me that on those the PJ nozzel is to low and starts to flow to soon for a road racer and the MX ones are hard to tune.

Attachment 230481

I couldn't afford to buy a good second hand TZ or RS unit. So I figure that moving the discharge nozzel.

Attachment 230483

And adding an adjustable jet from a large model aero engine could be worth a try.

Attachment 230482

On the dyno I have seen how a leaner mixture rev's on further and how richining it up for best power the over rev drops off.

I think that as the rpm goes up the mixture strength on an ordanery carb at max rpm goes over rich.

And at the moment I think the idea is that the PV is shutoff after peak power to get back to the correct mixture and by retarding the ignition at the same time extend the over rev, but I am sure there is more to it.

I would love to know more about how this type of carb should be used and/or setup.

The modern take on powerjets is to turn them off after peak power to extend the rev range. This assumes that you are happy for your engine to rev that much further past peak power & on many buckets perhaps this is not so good unless you have uprated the crank assembly. The jet will start to flow, depending on its position. Some don't seem to work well without an airbox if they aren't very prominant, or perhaps if the suction isn't so much (putting big carb on a smaller cylinder). In some cases they are best blocked off presumably if the air jet doesn't match very well & is tending to increasing richening with airflow as it is.

With all the talk about wanting to utilize only a couple of gear changes per lap, I would have thought that the solenoid powerjet was a gift from heaven.
A late model well tuned RS125 will rev to around 12400 if the PJ is disabled,turn the PJ function back on and it will go to 13800+.
Its so simple and you retain exactly the same lower rev power,but with easily another 1000rpm to work with you have the choice of adding teeth on the back, getting better acceleration from torque multiplication, or keeping the same gears - but increasing the terminal speed.
And from the dyno curves I have seen, most of the 100 buckets with short stroke lengths, arent even beginning to stress the bottom ends - with less peak rpm than the 54.5mm stroke 125 bikes or karts that will easily run to 13000 all day.

Ok now we have a stepper motor controled power jet........

The 'high compression brickwall' is no longer as hard as it used to be. With leaded fuel the compression ratio was 19,5; nowadays it is about 15. The 'brickwall' arose from the high expansion ratio (which is identical to the compression ratio). The higher this ratio, the more the burnt gases in the cylinder cool down before they enter the exhaust, thus lowering the resonance frequency of the exhaust system.
Riders complained that the engine would not rev, especially not in the lower gears, where the revs rose so quickly that the rising wall temperature of the exhaust pipes could not keep up with them. So you had cold exhaust gas and cold pipes.

The problem was to a large extent solved when the solenoid-controlled on/off-power jets were replaced with stepper motor-controlled jets that could continuously adjust mixture strenght, allowing the engine to rev more freely.

Attachment 229455

This is it. The stepper motor itself originates from a Fiat Uno where it regulates the idling rpm

Regarding the Aprilia RSW/RSA125 single, Jan Thiel told me that in seven years of testing the racing department had not been able to establish which was best: low or high inertia. I would choose low.....

Frits Overmars

To give you an idea of the main jet / power jet ratio: typical RSA-values are main 220, power 120. That means the flow area of the power jet is about (120/220)^2 = 0.3 times the flow area of the main jet. And don't shut the power jet until well past the rpm of maximum power or you will risk a maximum seizure.

Imagine the valve passes 60 cc of fuel per minute, but the engine only needs 30 cc. How would you go about that? You could open the valve for 30 seconds and then shut it, but by that time the engine may have drowned.
Open it for one second, close it during one second, open it for one second, sounds more sensible, doesn't it? That is why I quoted the valve's frequency: 13 Hz.
That means it can open and close up to 13 times per second. This again means it could open for 1/13 of a second and close the rest of the second, or open for 12/13 of a second and close during 1/13 s, or everything in between. And of course it can stay completely open or closed; enough possibilities to govern the mixture.

The ignition timing does not have to be changed when you use an electronic power jet. But both the ignition timing and the powerjet timing are means of influencing the exhaust gas temperature. A late ignition and/or a lean mixture both cause a higher EGT, so you can match the exhaust resonance frequency to a rising engine rpm.
And if you have that power jet available, the ignition does not have to do it all by itself anymore, so you can search for a timing that gives a better overall result.

When Jan Thiel was developing the Derbi DRVE (now known as the Aprilia RSA125) it turned out that with the engine in the frame the carb was tilted too far forward.
Jan then tried a Keihin that could cope better with the tilt-angle. But there was a contract with Dellorto...
I do not recall the exact date that the electronic power jet was first used. Must have been after Witteveen left the building at the end of 2004 (when he realised that he would be losing Jan Thiel to then-rival Derbi) because Witteveen was always opposed to the powerjet even though Jan Thiel had been asking for it for ages.
The first powerjet version had a stepper motor borrowed from a Fiat Uno where it used to govern idle rpm. In the Dellorto it operated a needle valve.
It was later superseded by a Keihin solenoid valve. Keihin just used it as an open/close valve but with some electronics of their own Aprilia turned it into a pulsating valve (13 Hz). The picture shows those Keihin valves on Simoncelli's Gilera RSA250.

Area 1.6 main = 2.010, less area 0.35 = 0.0962.
Main jet should now be 1.56,closest is 1.55 with the powerjet .
Try this without switching first to check equivalent egt to original setup.

Its a big one sorry all this talk of piggy back circuits.
These curcuits can also be used in numerous ways partically like a couple of them.

Refer: Silicon Chip January 2007 This kit stops the air conditioner in your car from taking engine power when accelerating such as when you're overtaking or going up a hill. It automatically switches the air conditioner's compressor off when the engine is at a high throttle setting and will allow the compressor to run with low throttle even when the cabin temperature setting has been reached. It also automatically switches the compressor off at idle. When the throttle position is normal the compressor will operate normally. The kit features an override switch, an LED function indicator and is supplied with PCB with overlay and all electronic components. > Recommended box UB3 HB-6013.
http://www.jaycar.com.au/productView...UBCATID=965#11

This kit operates a relay when a preset temperature is exceeded and drops-out the relay when temperature drops. The relay included is capable of switching small currents only, so a larger relay or switching device should be employed if switching mains voltages or heavy currents. Ideal as a thermostat, ice alarm, hydroponics applications, etc. A small trimpot is used to adjust the cutout temperatures for the relay in the range of approx -30 to +150 degrees celcius. €Kit includes NTC thermocouple.

http://www.jaycar.com.au/productView...UBCATID=965#11

http://www.jaycar.com.au/productView...o&form=KEYWORD
http://www.jaycar.com.au/productView...UBCATID=965#11
http://www.jaycar.com.au/productView...o&form=KEYWORD
http://www.jaycar.com.au/productView...o&form=KEYWORD
http://www.jaycar.com.au/productView...o&form=KEYWORD
http://www.jaycar.com.au/productView...UBCATID=965#11
http://www.jaycar.com.au/productView...o&form=KEYWORD
http://www.jaycar.com.au/productView...UBCATID=965#11
http://www.jaycar.com.au/productView...UBCATID=965#11
http://www.jaycar.com.au/productView...UBCATID=965#11
http://www.jaycar.com.au/productView...UBCATID=965#11
I mentioned 555 curcuit earlier. Most sensors give output in voltages 1-5 volts something along the lines below will enable a sensor to say pulse a powerjet?

One of the most fundamental problems in robotics is DC motor speed control. The most common method of speed control is PWM or pulse width modulation. Pulse width modulation is the process of switching the power to a device on and off at a given frequency, with varying on and off times. These on and off times are referred to as "duty cycle". The diagram below shows the waveforms of 10%, 50%, and 90% duty cycle signals.

As you can see from the diagram, a 10% duty cycle signal is on for 10% of the wavelength and off for 90%, while a 90% duty cycle signal is on for 90% and off for 10%. These signals are sent to the motor at a high enough frequency that the pulsing has no effect on the motor. The end result of the PWM process is that the overall power sent to the motor can be adjusted from off (0% duty cycle) to full on (100% duty cycle) with good efficiency and stable control.
While many robot builders use a microcontroller to generate the required PWM signals, the 555 PWM circuit explained here will give the novice robot builder an easy to construct circuit, and good understanding of pulse width modulation. It is also useful in a variety of other applications where the PWM setting need only be changed occasionally.
The 555 timer in the PWM circuit is configured as an astable oscillator. This means that once power is applied, the 555 will oscillate without any external trigger. Before the technical explanation of the circuit, let's look at the 555 timer IC itself.
http://www.dprg.org/tutorials/2005-11a/index.html

[TZ350]

I have been looking for Wobs old PJ posts too.

The solenoid Powerjet does lean off the BSFC curve BUT, what you need to get is that all it is doing is returning the fuelling to much closer to optimum.

Its not really "leaning it out "as such,it is dumping more of the available heat energy in the fuel - into the pipe, speeding up the wave action and thus extending overev available.

I remembered the first bit but had not joined the dots connecting it to the second bit.

PWM control of the powerjet is a very sexy use of technology,slowly ramping off the fuel flow against rpm, but in reality using a simple rpm controlled switched solenoid work perfectly fine.
Yamaha and Honda have used the switched powerjet since forever, its reliable and does the job.
Only issue you need to address is the jet size and switch point ( along with TPS value ).
Running Avgas as we are still allowed to do, means that the tuning is based around getting high egt numbers to create good power, with lots of com and advance - unleaded is the opposite..
Thus experience has shown that as leaded fuel works best with a lean condition at peak power, we only need to switch a small jet just past peak - to increase the pipe temp and
thus give better overev.
In the Keihin numbering this is in mm dia and switching off a .35 is perfect.
When running unleaded, as the GP bikes have for years, the fuel likes to be rich at peak to create the best power, thus we need to switch off alot of fuel flow to increase the pipe heat quickly enough.
In this case a .65 is needed to do the job.
On the dyno or on the track it is easy to tell if the switch point is a little too low, as it feels exactly like the bike has changed into another gear past 6th.
It jumps forward when the solenoid kicks in - making the fuel curve lean, too early.Do this enough - and bang.
Its critical to 100rpm, and is working perfectly when you dont feel it happen - the power just keeps going.
To do it on the dyno you have to run the bike in 6th to simulate the acceleration rate as seen in that gear on the track, and is easy to do running back to back run ups.
Changing the rpm number 100 at a time, lower in the Ignitech, reprogram on the fly and run again.
If the rpm is too high - nothing happens, as there isnt time for the heat to affect the pipe wave speed.

You must take into consideration the fuel being used, and how the factory engineers approached the problem.
Unleaded ( FIM that needs gloves and a respirator ) will go to 15:1 but must be run VERY rich to achieve best power with that level of com.
Leaded was run up at 19:1 in GP engines and at the end of the day the result was that the advance curves changed very little.
The big advance was in using the powerjet solenoids.
The unleaded scenario uses BIG powerjets ( 60 + ) to turn off the rich mixture past peak power.
The leaded setup was very lean at peak power, so only needed small ( 35 ) powerjets to keep the pipe temp up, over the top of the pipe.
Later of course that bastard Thiel came along and did the clever thing of PWM controlling the powerjet, thus even closer continuously matching the A/F ratio to the pipe
temp needed for max power.
Makes me sick just thinking about how clever he was, and how advanced the results became.
We are all just wankers floundering around in the mire of a mediocratic 2T wasteland - buckets.

I believe that the better fuel atomisation at the expense of the correct fuel curve would work on a 4T.
But as a 2T will throw its piston toys out of the cot at the first hint of a lean condition you have to correct the fuel curve to get the egt numbers progressively rising then stay stable in the overev.
Atomisation takes a back seat to A/F ratio accuracy with a well tuned 2T.
The FCR is a dead cool piece of kit - every circuit is very sensitive and responds immediately and logically to any small change.
1/4 turn on the idle air or fuel will raise or lower idle by 200 rpm straight off.
One main jet is exactly 40* temp change every time - great when you are watching everything in realtime on the dyno and data logging screens, for any indication of an issue or needing to correct a small hole in the delivery.

[Rick 52]

Cully mentioned at the previous meeting that they were going to sort out something for those riders that transferred from one grade to another. My son was relegated at that meeting from B grade to C grade after he changed bikes and was a bit slower on the new one. He's back in B grade now but is missing any B grade points from that previous meeting which is affecting his placing in the points table.

What is going to happen and when?

Onto it now Mike, this is all still very new and not yet perfect but is close, brilliant to get lap times and results printed out within minutes of the race finishing .
Any questions or suggestions can be emailed to any of the Auckland bucket committee .

Very happy with my results this weekend, I am hoping to keep up these results for all the work ESE has done helping with my bike

[TZ350]

TZ the Belzona product you used on the piston, What was it?
I have found an epoxy that is good to 2000F or 1100ish C Meant to be fuel resistant as well?

Please tell me more about this epoxy and where can I get some?

[husaberg]

Please tell me more about this epoxy and where can I get some?

Have a look at the products yourself something, well for almost everyone.

http://www.aremco.com/products/

the one that caught my eye initially was this.http://www.aremco.com/product/a15/ but used in other applications.....

ten carrot actors

Never used it or no idea where to buy it i seen it in a Mag and Googled it it seems it can withstand EX and such like but its all from the seller's info rather than third party. THe company seems legit make refactory stuff and all that kind of stuff.......

Pyro-Putty®
These high temperature ceramic and metal-filled pastes are ideal for repairing pinholes, warps and cracks in manifolds, headers, exhaust pipes, mufflers, and more. Pyro-Putty metal repair compounds bond tenaciously to cast aluminum, cast iron, steel, and stainless, and are easy to apply, cure, machine and clean up.
Pyro-Putty® 1000-K Kit
1400 °F for Cast Aluminum Repair
8 oz Powder, 4 oz Liquid
Pyro-Putty® 2400-K Kit
2000 °F for Cast Iron, Steel, Stainless
8 oz Paste, 4 oz Thinner

[TZ350]

Thanks .....

I am looking for something better than Devcon for sealing the exhaust port dam in my next cylinder.

[Gigglebutton]

Thanks .....

I am looking for something better than Devcon for sealing the exhaust port dam in my next cylinder.

Could I weld it Rob?

[husaberg]

thanks .....

I am looking for something better than devcon for sealing the exhaust port dam in my next cylinder.

tig...............screw.........

[TZ350]

Could I weld it Rob?

Thanks, but screw and glue looks like an easy repetable way of doing it.

tig...............screw.........

The last one was held in place with a couple of screws, and that seemed to work OK.



But I suspect the Devcon glue I used to seal it will burn away in due course. I like the exhaust port dam idea and want to give it another serious go.

[TZ350]

Tim sent the MyLaps link below.

Onto it now Mike, this is all still very new and not yet perfect but is close, brilliant to get lap times and results printed out within minutes of the race finishing .
Very happy with my results this weekend, I am hoping to keep up these results for all the work ESE has done helping with my bike

Hi there,
the results of the third round of the 13/14 season of AMCC bucket racing from yesterday are attached, for publication in the newsletter & website.
Regards,
David Diprose

Attachment 287540

And Printable PDF.

Attachment 287539

Team ESE rider Rick52 took two more wins in the A grade points racing, and I hear that he was the only one to run (only just under 30's, F4 race 2) in the 29's yesterday.

So the finishing order was 2T 4T 4T 2T in the 1st A grade points race and 2T 2T 4T 4T in the 2nd, looks like the time is coming when anyone wanting to win A grade races will have to think about building themselves a fast 2T.

Hi all,
The results of Round 3 are now on Mylaps. You can get straight to them with this link: http://www.mylaps.com/en/events/956487
Tim

[F5 Dave]

This PJ stuff is all becoming a moot point atm. I don't know what sort of happy pills were being slipped into my weetbix when I dummied up the manifold on the engine on the bench, but I wish they would start again as there is no way this KX carb is going into the RS frame without a fairly major cut & shut.

Problem is the case reed conversion is too low so I'd need to run the PWK at a 40 degree angle which ain't going to happen, or accept a bit of a bend & some unwanted length as a compromise but at least get the PWK carb cw solenoid. . . except the frame needs a rethink. It could almost work if I assembled it & fit the engine to the frame. . .but that means dropping the engine for a jet change & even I think that's unworkable.

So now I'm stuck with the poxy RGV carb & trying to think how to make an external Solenoid PJ conversion. That bit is easy(ish) enough, but the tricky bit is mounting it to the carb where it wont get broken during a jet change (small window to pass through) or made sturdy enough not to leak given wear & tear.

Pass the grinder.

[Flettner]

Put a throttle body on it, don't bother with the carb. Throttle body much more compact.

The F9 is losing it's EFI, a backwards step. Seems it's not in the "spirit of the era" if I want to keep racing it in VMX. Fair enough, we will teach them ( VMX pre 75 ) a lesson in how to hot up a rotary valve engine even with a carb on it. Out to the pattern shop to make up a new barrel with modern porting, eye ports etc. More than one way to skin a cat, apparently.
I'll show them " spirit of the era"!!

[speedpro]

That shock mount crossmember is a problem for sure. I have looked at all sorts of options like cutting it out and moving the shock to the side and even rotating the engine and mounting it forward with the cylinder near vertical, possibly with a jackshaft. Moving the engine forward needs more investigation though I see problems with chain geometry and possibly clearance to the front wheel