ESE's works engine tuner

[F5 Dave]

All good stuff. I have an antiquated suzi RG50 with a million years development (bit like uk TS50 but watercooled) in an RS125 chassis, but have a Derbi to go in one of these days (Like when I'm finished my F4 100). I'd read a bit about your racing in CMM mag.

[koba]

Here is some you tube of some of our races http://www.youtube.com/watch?v=CaT6R...eature=related

Looks very good. I like the track.

[pugs]

What do you do for a living, Pugs? Archeology? I wrote that stuff 33 years ago! Where did you dig it up?

hahahaa thats classic!!!

Lol... Oh well, I thought, philosophy needs to be classic

Is there any one out there with an English laguage version of the Frits pipe article , or , alternatively can recomend a good on-line translation site.
Frits no doubt finds it " old hat " but us beginers need all the help we can get . Finally , it`s good to see Neels popping in for a look now and then !
Regards to you all , Trevor

Just kidding, I cannot spare the time and I am sure neither can Neels. But just in case someone produces an English translation, I would love to get a copy.

While my dutch is not that good, actually I'm working on it... (need to see dictionary every now and then..)

[husaberg]

One of the European corespondents has one of these the HP is not too shabby for either really considering the design of the twin is quite unique.
Shame about the Albion box.

Yes a couple of my single cylinder Alpha bottom end's are on that web site, and the picture you attached of the Alpha test bike with the very early single cylinder engine is one of my bikes although it no longer looks like that. The Alpha twin on the web site is one of 4 machines that "survive", but its not mine. That is the sister bike of the one damaged in the fire, which is being rebuilt slowly by its owner, the frame is now straight thanks to young Sprayson, there is now a replacement gearbox sourced from New Zealand, he has a spare engine, so heading in the right direction. I'm now making a replica Centuri engine since I do not want to trash another original Alpha engine on the race track, heads and crankcases already cast I still have to finish the core boxes for the cylinders, but that could take a week or two yet! My bike is one of the two DMW versions used in the 68 TT, neither of which managed a lap during the race. Another little snippet is the bikes run on a 29 mm Delorto with an 1800 main jet, yes not a miss print, one of the short falls of using a single carb and twin disc valves, however having said that, the final version did manage to produce 48 bhp at the crank, and had an amazing appitite for primary chains.

The Merlin engine in your photo's was very popular with the Kart people, there were 3 versions to my knowledge a 200cc, 250cc and a 350ish cc engine. A very good little engine, but sadly not developed like so many other good ideas.

The Arrow engine is now becoming popular again in Classic Bike racing in the UK, as you said the engine is very similar to both the Adler and TZ, with the same bore and stroke. The bikes currently racing in the UK are much more like the TZ internally, than an Ariel. The Ariel came in multiple shapes and sizes, 200cc, and 250cc with the latter available with the standard single carb, or the twin carb sports version. All bikes had the basic very stiff pressed steel spine from, which was very advanced for its time and trailing link front forks which are very heavy, the Leader had the extra body work for every day transport, and the Arrow was the bare sporty bike. Good machines.

Another interesting British engine was the Royal Enfield GP5 designed by Hermann Meier, which I think was one of the first 4 transfer port engines around, and way ahead of the Yamaha versions, and not counting the MZ boost ports. Hermann was a very clever engineer who also tuned the very succesful TT Arrow ridden by Mike O'Rourke.

Enough now lets get back to modern stuff, so I can revise my designs for the Centuri core boxes!

More here http://www.lortim.demon.co.uk/alpha/index.htm

Here is some you tube of some of our races

On the You tube clip posted further back i seen this neat idea. The racing footage was also neat by the way as well.

http://www.youtube.com/watch?v=aAN23...eature=related

[gamma500]

Hey all!

I bought some snowmobile engines couple of days ago, and I was surprised to see transfer port dividers also in the crankcases.

Any of this threads readers ever tested these kind of transfer dividers?

[cookie1965]

Anything well just about anything can be made to work given enough time, money and more importantly determination.

I concept is great but why one throttle body?
What is the outcome you are after drivablity, fuel consumption,Tune-ability, emissions or performance. ?
The main issues i see is that carbs are light and simple and relatively specking. Ie no battery/alternator, fuel pump regulator ECU etc.
I am not knocking you because it is great to actually do it rather than just thing about it or just ruling it out.
What sort of fuel pressure are you envisaging?
I remember the Cagiva system involved huge pressures.
The biggest potential advantages i see with fuel injection are economy and emissions drive-ability but maybe, i am short sighted about this.

The one thing i did pick up from a few pages back was the split system with each set of injectors handling half the revolutions. So two injectors on each cylinder running each fueling alternate revolutions. Which should solve a few of the problems with doing it in the past.

Yup, carbs are simple and I don't have any problem tuning them. The bike I'm putting this on (RZ350) has a charging system so no power worries and I have to build a harness for it anyways, might as well do the FI at the same time. I'm doing this more as an experiment - kind of a "can I make this work" kind of thing. The single throttle body concept was for simplicity really. My thinking being that since the throttle body is only responsible for the metering of air not fuel one large TB would be sufficient. I'm not expecting any performance gains, but if I could match the performance with simplified tuning (once base maps are written) and driveablity I'd be happy. Honestly don't know the fuel pressure, I purchased a kit with pump and regulator included. I'll put a gauge on it when it's running to monitor it. I considered 2 injectors per cylinder but decided on a single for the prototype. A low speed/high speed injector system may work better, we'll see I guess. The cylinders are out being bored for new pistons and then assembly, wiring and fuel system to build.

[rgvbaz]

Glad you like the youtube action.

Mind I must try to get into the garage to get prepped for this years races!

Dave

Ps. The track is Rowrah Kart Track in Cumbria, Its not bad but I prefer Llandow in Wales, then Whilton Mill thats just (2hrs) down the road from me. These are the only three race tracks we use and all are for karts. Some of us do go to the Dutch end of year 4hr race in Croix France http://www.youtube.com/watch?v=L0piJ...2&feature=plcp, been once... it rained... bike blew up! Its still ace mind.

Anyway now back to tuning engines.

[twotempi]

The common two-stroke conrod length ratio is twice the stroke with some variation. For a 50mm stroke engine what is the accepted ratio limit for longer rods.

Calcs show the that the piston acceleration is increased therefore greater stres on the piston pin little end assembly, and also a slightly increased dwell at the top of the stroke.

What are the other pluses anmd minuses of say a 110mm rod with 50mm stroke. What would the mechanical rev limit be estimated to be ??

[nasone32]

longer rods on a two stroke give

-less friction of piston against the cylinder wall, due to different rod angle
-increased time area if restoring port timings after rod change (port durations decrease a bit when you put a longer rod, by restoring them you gain area!)
-increased crankcase volume
-decreased maximum acceleration
-increased weight (usually)

I found a nice paper here (on 4 strokes), with example quantities calculated for various factors, so you have a better idea of what happens
http://www.rustpuppy.org/rodstudy.htm

maximum safe revs are hard to tell without knowing the engine, depends on piston+rod weight and strength, crankshaft balancing/stiffness

Personally i'm happy with long rods when looking for maximum power, but on a fixed-ratio 100cc kart I would be careful, they run often out of powerband and a bit higher crankcase compression is useful there (maybe can by fixed with epoxy)... Unfortunately I don't have such experience in karting

[wobbly]

For a race engine there are no minuses to a long rod.
Using 110 in the 50 stroke means you are on the money with the Aprilia RSA - that went OK for a 2T.
Increased weight and increased small end load dont mean shit unless you are reving the 50 stroke to 16,000 - then all lighweight parts are needed.
In a direct drive kart engine all the components are very light due to the 22,000 rpm they spin to, and the tradeoff between peak power and
bandwidth is biased in favour of better bottom end, so the case is relatively small.

[SS90]

I see the Europeans have joined in force...this should be good.

[Grumph]

I see the Europeans have joined in force...this should be good.

So what do you count yourself as now ? And where the fuck are you when I've got a bike to test ?

You promised faithfully you'd be available to test anything i built.....

I have doubts though....a couple of years of German food and beer and you'd be bigger than me now....Never get on a 125 again.

[F5 Dave]

and there are tremendous rumblings in Prussia, although that might be something to do with the sausages.

[SS90]

So what do you count yourself as now ? And where the fuck are you when I've got a bike to test ?

You promised faithfully you'd be available to test anything i built.....

I have doubts though....a couple of years of German food and beer and you'd be bigger than me now....Never get on a 125 again.

My leathers do seem slightly more "spray on" these days............

[breezy]

ss 90, way back, in this long thread ,you mentioned and showed pitures of old cast twin transfer ported barrels that you added piston controlled boost/ transfer ports to. is there anywhere on the net which gives any more result based info i can read / down load. thanks in advance...