After that, it seem redundant to mention that the AMC motors referred to were actually made in France by an outfit coincidentally called AMC....so blame the French again, this time for wob's early sexual adventures.....
Low personal B.M.E.P.
After that, it seem redundant to mention that the AMC motors referred to were actually made in France by an outfit coincidentally called AMC....so blame the French again, this time for wob's early sexual adventures.....
Forum whore
Early 36mm EI carburettor. An interesting thing about these carbs is the 36 refers to the size of the carb at the engine end and its actually 33mm at the slide. I suspect the Lectron carbs are sized this way too. They are both very different to other carbs.
Other traditional manufacturers size their carbs at the slide so apparently in the industry there is no hard and fast rule about how carbs are made or measured.
To shorten the carb I cut the front and back off it and pressed in a plug thats the right size for the manifolds we use on the GP engines.
The plug was turned to form a 24mm venturi right behind the slide where carbs are traditionally sized and where people said mine should be measured too. On this carb the front part is a flow straightener and fuel dispensor and the 24mm venturi is the high velocity, low pressure fuel atomiser for better drivability.
I expect any fuel droplets however small will just burst into vapor when they pass through the region of low pressure in the 24mm venturi. In the pressure recovery area after the venturi we should have a very well homoginised mixture of fuel and air being inducted into the crankcase.
There is no main or pilot jet in a EI carb, the fuel metering is done entirely by a needle tapered only on one side, this taper faces the engine and purportedly gives better fuel atomisation than a conventional carb.
The mixture strength on the EI carb is adjusted by winding the needle up or down, a bit like shifting the clip on a conventional needle, and if that's not enough adjustment then another needle with more or less of a taper can be used.
I think that even if this carb flows more air there won't be much if any of a power increase as I think the inlet port itself has become the restriction on air flow into the crankcase now.
An old Suzuki GP125 rotary valve is sitting ontop of my new RV, now thats a very healthy 23% increase in area.
The next move is to build an engine with the bigger rotary valve so that the taller but narrower inlet port stays fully open for longer and can give the specific time area required for the target RPM and BMEP.
Anorak
I was suggesting a way via PM the other day for TZ to shorten up the manifold it would have been hard work and was complicated.Originally Posted by TZ350
An old Suzuki GP125 rotary valve is sitting ontop of my new RV, now thats a very healthy 23% increase in area.
The next move is to build an engine with the bigger rotary valve so that the taller but narrower inlet port stays fully open for longer and can give the specific time area required for the target RPM and BMEP.
I was half way through drawing it up when it occurred to me that this would be better not to mention easier.
Forgive the photo shop but it would be easier to do for real.
I think it should be able to clear the primary gear which is why the simple Aprilia/Rotax style wont work
I am not so sure that inside out manifolds are reverse engineering but i like it.
It would be great for TZ to show the box of carbs he has tried on the GP so far.
Kinky is using a feather. Perverted is using the whole chicken
Race it don't store it !
Hi can anybody tell me why I have this strange burn pattern on the crown of my piston ? It has done about 3 meeting including last years GP .The pattern that looks like a number 1 was light carbon and easy to remove ,at Taumanuni 7th Jan it was running rich so I changed the main and it ran much better ..The engine is a TF125 Cheers Rick
Forum whore
Its an omen from the Gods Rick, best you turn up at the next GP.......
Hi can anybody tell me why I have this strange burn pattern on the crown of my piston ? It has done about 3 meeting including last years GP .The pattern that looks like a number 1
Forum whore
Carbs .......
Race it don't store it !
Haha cheers Rob but I think I need another 5+ horses to play at the front with the big boys..
Forum whore
Rick ... you are one of the big boys.
Bring you engine around with the head off so we can put a degree wheel on it and have a look at whats there, maybe there is something that can be done.
Was worth a crack
Its already a well sorted kart track racer, dont mess with it.
TZ I'll slip you a fifty not to touch it.
Fair weather rider
something of interest:
http://www.drrinc.com/pdfs/higher_compression6.pdf
there's no date and a few of the technical bits aren't explained, but it does involve small aircooled two-strokes so it could be useful (or confusing)
Anorak
I am sure Frits would say Air cooling has no relevance in a racing engine.something of interest:
http://www.drrinc.com/pdfs/higher_compression6.pdf
there's no date and a few of the technical bits aren't explained, but it does involve small aircooled two-strokes so it could be useful (or confusing
I have attached it as the link wouldn't work for me why, i know not.
In the reference material 1982 is mentioned, but it could just be a paper number.
Anyone have an idea how to work out the size of a radiator needed. As a rule of thumb can they be sized say with HP.
Assuming they operate at similar speeds and conditions with similar water flow. or is it suck and see?
Kinky is using a feather. Perverted is using the whole chicken
Forum whore
The paper covers a corrected compresion ratio range of 6.6 to 13.6
Fig 14 "Full Load Knock Range" shows some ignition timing values and a curve that looks very familiar.
Forum whore
Grabed this so that people who may not be familiar with Bucket Racing in NZ can see what the rules are.
My 125 2-Stroke is limited to Air Cooling and a 24mm Carb.
Developing a Bucket road racer, particularly a 2 stroke, it is not just about outright power, the tracks have to be considered and the most appropriate power spread developed. On tight go kart tracks drive out of the corner and reducing the number of gear changes required need to be looked at. Then there is handling and suspension set up, tyre pressures etc. It’s affordable and there is enough challenge here to keep a developer interested for a long time.
The easier it is to ride the easier it is to ride fast ......
Forum whore
It's the same everywhere in racing (except dragracing): engine power may give you tenths of seconds; chassis setup will give you whole seconds.
Hardcore Biker
Hey TZ, nice looking carb you got there!I like blue!
As you observed everything looks very similar to the Lectrons. I used to have a 34 and now a 40 - both minus 2mm at the slide. Great carbs, easy to tune, crispy and steady at idle on the very first start-up. Hard to tune though, unless you purchase a couple of rods. (Thankfully I got an amazing deal on ebay once and got myself about 20 at zero cost)
Here's the dimensions to the 40 lectron:
and here's some carbs I have in EndMod data, if anybody wants them:
http://users.uoa.gr/~sph0800108/mode...od2T/Carbs.rar
There's 2 PWKs 38, the two lectrons and one Dellorto 30.
Good idea about pointing out the regulations.
Since you're kind of near to Malaysia and Thailand, why don't you get one of the mopped engines from there??
They're aircooled and below the 125cc limit. Reed valved and quite modern for low cost production engines, in every aspect.
We have the same mopped bikes here and we tune those engines a lot. It's actually the engine I tune myself.
I have tons of photos here if you're interested: http://s736.photobucket.com/albums/xx5/Vag1-2/
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