ESE's works engine tuner

**richban** · 3rd February 2010, 23:27

Originally Posted by TZ350

I will be able to finish dialling in the carburation when I get the filter then its of to the dyno.

I will be very interested in the results will you do a run with and without the filter. I had some interesting results from the intake testing at Manfield. I am back to running straight from the carb bell-mouth. The 16mm trumpet I tested gave me quite a flat 3/4 to full throttle feel and (seamed) like less power. It did have a green ring that developed 5 mm out into the trumpet from the avgas. So I figure it is very close. I will have my bigger volume 28mm carb body finished soon so a little more volume might be just what it needs. Or not.... They call exhaust design a black art ... I think intake is just as frustrating. And of course change one and you need to look at the other. Speaking of exhausts I have 2 revers-cone megaphones to build. That should open up another can of worms all together....

**TZ350** · 8th February 2010, 16:28

Hi Rich, interesting to see how your getting on, interesting carb idea.

For us the game plan is; the new air filter should arrive this week, then we can take the "Flying Vacuum Cleaner" to MtWelly for Saturdays practice.

If we can get it to carburate satisfactorily then the following week its off to the dyno at Johns place with Speedpro to test our bikes, if he hasn’t got sick of waiting and beaten me to it by then.

Untill then here are few pictures of a 1970's water cooled 4 cylinder rotary valve 125cc Yamaha road racer, 42 RWHP at 18,000rpm photoed by Chambers at the clasic meet last weekend.

**Bert** · 10th February 2010, 16:31

I know this thread is well beyond this...
but I though it might be useful; if it hasn't been posted before.

http://ypvsbox.free.fr/pipedesigner_en.html

and this

http://www.gifford.ca/hydroform.html

**TZ350** · 10th February 2010, 16:42

Thanks for the link Bert, looks interesting.

More on trying to get the plenum sorted. I fitted short track gearing to reduce my speed in the driveway and had another go at the jetting, things are starting to come right with a 180 main jet, the bigest I have, it was about 130 before. The plenum seems a bit prone to load up with fuel making jetting with short test runs in the drive way difficult.

The motor has a bad case of the blarrrrs and then picks up very strongly, it reminds me of when I tried a GP125 disk in a GP100. The 100 would have the blarrrrs then hit real hard and then not rev out. The 100's inlet was out of sink with the rest of the motor.

Because of the big inlet on the plenum set up, even with the std GP125 rotary disk the inlet port time area is excessive for max power at 9,000 so I will try reducing the inlet duration tomorrow by fitting a GP100 rotary disk and also get a few more bigger jets to try.

There appears to be no standoff in front of the carb when its driving well but spits a bit of fuel out when its got the blarrrrrrs. Once or twice I got a good run,changed into second and gave it a handfill, the beast sure felt strong, although a little rich.

It starts so easy and pulls away like a dream although not very crisply, and I think I will be able to fix that.

Things are looking good, it hasn't blown up yet and might actually work.
.

**TZ350** · 12th February 2010, 16:11

Changed the rotary valve today, timing is now 135/40 opens 135 BTDC closes 40 ATDC, 175 duration, down from 205. Port window area 9 cm#. The big surprise was that when we took the cover of, there was a good ½ cup of raw petrol mix sloshing around in the bottom of the plenum.

When the motor is pulling ok there is no discernable spit back through the carb, so I am not sure where this excess fuel is coming from, dropping out, being spat out of the engine, choke stuck on, who knows. But I was right when I thought it was getting loaded up.

With the new inlet timing the thing runs better but a pool of fuel still develops in the bottom of the plenum……..

Pic-01 bike ready for open-heart surgery
Pic-02 Plenum (after I dried it out)
Pic-03 with the side cover off
Pic-04 new and old rotary valves
Pic-05 Thomas had the thing apart and back running in about 45 mins, the other guys are straightening Chambers bike up after he and Avalon took turns throwing it down the road at Taupo.

Some days I feel more hopefull than others that I will get this thing to run properly.

**F5 Dave** · 12th February 2010, 16:50

So the calorific value of petrol is 45.8 MJ/kg and a 1/2 cup is say 125cc, if it was water that would be ~ 6 megajoules of energy, but petrol is a bit lighter.

How big an explosion is that? There must be some easy conversion to TNT, the one I found was dicky & I lost interest

**TZ350** · 12th February 2010, 17:40

Originally Posted by F5 Dave

So the calorific value of petrol is 45.8 MJ/kg and a 1/2 cup is say 125cc.......How big an explosion is that?

Thankfully not very big, the petrol still needs an oxidiser and 875cc of air doesn't go far..

..thank God, its less dangerous than your average petrol tank...........but I won't be running this setup with nitro, not even for shits and giggles.....

**richban** · 12th February 2010, 19:26

Originally Posted by TZ350

When the motor is pulling ok there is no discernable spit back through the carb, so I am not sure where this excess fuel is coming from, dropping out, being spat out of the engine, choke stuck on, who knows. But I was right when I thought it was getting loaded up.

:

You could always make a drain out of your plenum so you could measure the excess fuel. Time / cc's collected. Then change the volume and see if you get less. Might give you some gauge of efficiency.

**TZ350** · 12th February 2010, 20:07

Originally Posted by richban

You could always make a drain out of your plenum so you could measure the excess fuel. Time / cc's collected. Then change the volume and see if you get less. Might give you some gauge of efficiency.

I have fitted a carb main jet as a drain/air bleed and also thought of using the pumper part of a carb from a weed eater to pump the surplus fuel back to the tank. And I also have plans about how to reduce the volume of the plenum from it's current 1 litre volume in a graduated way. But had not thought of measuring the excess fuel as an indicator of how air flow has change inside the plenum, that’s a good idea, I will try it.

**Yow Ling** · 13th February 2010, 08:08

Originally Posted by TZ350

I have fitted a carb main jet as a drain/air bleed and also thought of using the pumper part of a carb from a weed eater to pump the surplus fuel back to the tank. And I also have plans about how to reduce the volume of the plenum from it's current 1 litre volume in a graduated way. But had not thought of measuring the excess fuel as an indicator of how air flow has change inside the plenum, that’s a good idea, I will try it.

if you filled the bottom of the plenum with resin so the re was nowhere for the fuel that dropped out of suspension to puddle that might mean you could go bit leaner on your mains. the extra fuel you are feedin it is probably just to account for what goes MIA . still give you plenty of volume in your plenum just nowher to store all the extra gas

**Buckets4Me** · 13th February 2010, 09:14

do we have to wear fireproof suits ???
I think I might just go out and get one anyway

brings new meaning to burning off the oposition
or toasting them
or blowing them away lol

dont upset TZ350 he may FLAME you

HAHAH ha

ok I'm off to do some work around the house now
see ya tomorow