I have been looking at the rear rotary again.........
And wonder if a TF100 case could be fitted with a RG cylinder and an upside down rear rotary valve thats driven by a toothed belt.
As 14,000 rpm is only 233 Hz one also wonders about driving a slide valve back and forth across the inlet using two large elctro magnetic voice coils driven by a 4 pole generator on the crank.
Might be able to have fast opening/closing and a longer fully open period than you could get with a conventional rotary valve.
If it worked it could even lead to variable inlet timing. Then there is phneumatic valve actuation............ lots of possibilities.
Actually when I think about it, one could use the crank generator to charge two capacitors, one for opening the other for closing. And use an Ignitech programmable ignition to trigger them that way the inlet timing and duration could be continuously variable throughout the rev range and throttle position.
Been there and helped do that, and in this guise the reed was still a little quicker.With the RV attached to the reed box.
May be able to do a bit better now though - but still alot of techo brain damage involved.
Turning the RGV cylinder around and having a rear facing pipe under the seat, holds a certain facination for me though, and maybe Rob will still go with this option.
Been there done that, well with a RG barrel anyway. Did it mostly because old school MZ racers had it(and they are fucking cool), making the pipe was way easier and according to tests done by Velocette in the '30,s straight pipes have a small HP advantage over pipes with bends in them.
Compare Pornography now to 50 years ago.
Then extrapolate 50 years into the future.
. . . That shit's Nasty.
The RSA was developed simply because the KTM 125 reed was faster than the side valved Aprilia/Derby/Garelli.
Its only "dominant" now because no one else is in the sand pit.
The KTM came good in 2005 but still didnt win the riders title (that Talmasci what a cock) then got its arse kicked in 2006 by the side valved RSW, the RSA was only intrusted to Bautista for the last couple of races and then only 3 riders the following year. The KTM was good but the Italians always came back with something better. There was some young rider who swapped his KTM for a Derbi RSA last year, name was something like Marquez, think he did quite well.
Had some pictures of the RSA inlet and disc but cant find them now, the inlet is enormous and the disc timing looks insane, guessing around 240+ deg?
Can't believe the 2 strokes will be gone from GP's its just not right!
The KTM came good in 2005 but still didnt win the riders title (that Talmasci what a cock) then got its arse kicked in 2006 by the side valved RSW, the RSA was only intrusted to Bautista for the last couple of races and then only 3 riders the following year. The KTM was good but the Italians always came back with something better. There was some young rider who swapped his KTM for a Derbi RSA last year, name was something like Marquez, think he did quite well.
Had some pictures of the RSA inlet and disc but cant find them now, the inlet is enormous and the disc timing looks insane, guessing around 240+ deg?
Can't believe the 2 strokes will be gone from GP's its just not right!
GP is meant to be the highest echelon in motor sport. It makes me sad to see it turn to mega $$$ proddy racing..
We can only hope that 2 strokes are accepted again in the future.
Originally Posted by sil3nt
Fkn crack up. Most awkward interviewee ever i reckon haha.
If someones got enough folding I would soon knock up and guarantee an aircooled with 24mm carb that makes an easy 38crank = 32RWHp,as this only represents a bmep of 11.3 bar or 164psi - so the carb isnt the limiting factor at all,in fact it would help the spread.
The complete how too......... of the Jaycar CDI kit
For those interested in F5 and RG50's
R/H Crankcase Oil Seal p/n 09283-28013 $10 (or was 2 years ago)
L/H Crankcase Oil Seal p/n 09283-18004 $5
Gear Change??Oil Seal p/n 09285-12006 $7
Rod kits from later RG/RMX/SMX/TS/GT/RV/MT50 have oiling slots.
ConRod p/n 12161-04710
B/E Brg p/n 09263-16034
L/E Brg p/n 09263-12023
Pin p/n 12211-04711
Washer p/n 09160-16021
Wiseco Piston 826M04100 (std bore) Fits JR50 78-2004 and Kawa KDX50 03-04
The RG50 has only 3 thick clutch plates, 4 thiner TS/TF/GP100 or 125 and a steel will fit for a much better clutch.
Clutch cover gasket p/n 11482-13710 $22
Cly base gasket p/n 11241-04710 $14
If anyone wants to sell any RG50 engine parts or general junk, please PM me..........
For those that wan't to experement with different carbs for their bike........ all sizes of copy cat Keihin flat slides, 24-28-32-34 http://www.alexwarehouse.com/OKO-car...30mm_p331.html
Cheap enough to modify or play with.
Some Wobbly tech quotes that I thought should be kept together..........
Originally Posted by wobbly
Having a single Ex port will limit power capability - end of story.
And trying to get the big bmep numbers means that the only way is to make the ports higher and wider.
Blowdown is the single most important number in the spec sheet.
The other thing that seems to be overlooked by many is that Hp=T*rpm.
An engine with a 50mm stroke "should" be peaking at 13000,and be running on to 14000.
But when you have to use very high exhaust timing this tends to shut down the power over the top.
Also anything but a square bore/stroke ratio makes it doubly hard to get the port areas needed. With tripple Exhausts and as much transfer width as can be crammed in.
As its a big bore at 56mm the
Ex area is low but this is of lesser importance than the blowdown. Notice the relatively low bmep needed to achieve the power at 13000, with very normal timings of 194/132.
Originally Posted by wobbly
Case com is a very complex subject but a few rules of thumb apply.
The higher the bmep of an engine then the higher the delivery ratio, thus a larger case can store the higher volume of ingested air at a higher pressure and this is then available to the transfer ducts.
But the quality of the duct and port geometry also affects the case com required.
The smaller the case vol (higher ratio) the greater the pressure rise in the case as the piston drops - this suits compromised transfer ducts with little or no inner wall shape, as it helps force the flow around thru the ducts quicker.
Good duct/port geometry allows the use of a bigger case as they dont need a large pressure ratio across the port to initiate good flow.
Lastly is the effect of the pipe geometry, the diffuser sucks like hell on the Ex port around BDC, pulling flow thru the transfers, and it is important to match the pipe diameter ( and thus the diffuser included angles) to the transfer port/duct geometry.
Suck too hard on crap transfers and they loose directional control - giving greater short circuiting out the Exhaust port.
Thus you have a Catch22 in that you need a small case to speed up the flow, but this limits the available stored mixture, and you want to suck on the transfers as much as possible, but no so much as to loose the control of the flow direction - or to speed up the loop velocity excessively thus reducing the trapping efficiency..
One myth that needs busting here is that the bulk of the flow thru the transfers is initiated by the piston dropping.This happens in lawn mowers, not racing engines.
Pipe diffuser suction when the piston is around BDC forces the bulk of the flow volume, NOT the pressure in the case forcing flow up the ducts.
When the transfers open there is more pressure in the cylinder than in the case.
Thus we get flow reversal at the initial transfer opening point.
This also means that the transfer port that opens first - flows last, as it has the greatest flow reversal affect,down the duct.
In general, high bmep engines that by default will have good port/duct geometry, will like a case com down near 1.3:1, lower performance engines with crap transfer/duct geometry will perform best with the ratio higher, up near 1.4:1.
Thus as you develop an engine, increasing its efficiency with better porting, then this will allow the use of a bigger case, and bigger pipe diameter/vol, to work with that - the two go hand in hand.
Originally Posted by wobbly
Both Fletchers and Ulrich do heavy wall alloy tube in 6000 series.
This plates just fine according to Grant at the platers down South
Originally Posted by wobbly
Here is an oval to round spigot for Robs GP100 with RGV cylinder.
36mm pipe ID, oval shape at the duct exit is 36 wide by 27 high = effective area of a 31mm round..
This nozzle effect doesnt work on single port engines - I have tried.
Re stinger nozzles - if running a 18mm nozzle on a 100cc then you could connect a 20mm stinger tube to it in basically any length and this would not affect the power at all - in fact using the nozzle with a tapered section out to the bigger tube makes more power.
Aprilia/Derby twins do this as the top pipe has a stinger 60mm long, the bottom one is closer to 220, but the effect works on any 2T.
Originally Posted by wobbly
Honda first used the staggered transfer setup with the RS125/250 and was developed by Helmut Fath ( my hero) as was Exhaust stinger nozzles,for the factory teams.
With the big T port they opened the main first by around 2*, the secs and boost ports last.
Aprilia later came along with a 3 port Exhaust setup with huge aux Ex ports, they now have the mains lower to allow much bigger aux Exhaust area, with the secondarys and boost opening first.
All have the axial angles set at around 22* - 12* - 55* to clear out as much residuals from within the loop area as possible.
The big hooks on the secondarys also flips the flow over on itself under the boost, to clear this area out as well.
Greater flow reversal occurs when there is insufficient blowdown STA,and the TZ250 sacrificed blowdown for more transfer area, something we now know is a mistake -
Originally Posted by wobbly
Only Yamaha stuck with the wank flat roof scenario way after the use by date, and got their arses kicked for years in GP.
Till they finally bought a CNC controlled Jante machine from Czech, went square bore/stroke and using the 500 cylinders on the 250 easily won the champs in 2000 with Olivier Jaques.
The secondarys facing each other relatively flat will always collide, but the hooks rotate the flow under the boost as it exits the port ( easy to see with the tap water Jante trick),clearing out a big "dead" area
in front of the rear port.
All modern race engines have a nozzle restriction at the flange face, as big T ports and tripple Exhausts loose alot of velocity going into the header.
Rule of thumb is a 75% of the effective EX area at the flange.
Stepped oval duct into a round flange does work, but I have used a CNC oval to round transition in the spigot for years, as has Honda in A kit, and Aprilia factory engines, this works way better.
Here is a sim showing my new 400cc F3 engine, with and without the spigot nozzle.
The stinger nozzle effectively removes the stinger tube length from the equation - it was developed for Spencers NSR that had one stinger 150 long, the other was 450. The nozzle is around 2 to 3mm smaller than the tube stinger .
Tech content gathered together for easy future reference ..................
For those that wan't to experement with different carbs for their bike........ all sizes of copy cat Keihin flat slides, 24-28-32-34 http://www.alexwarehouse.com/OKO-car...30mm_p331.html
Cheap enough to modify or play with.
If someone is thinking of getting some/one of these let me know could be interested in splitting shipping costs.
I havnt seen that shot of the RSA before - what makes it interesting is if you rotate the view 90* so it looks like a "normal" engine, the port is the opposite shape to what is seen in that application.
Its tall and narrow, maybe this is part of why they work so well, apart from the symetric feeding of the transfer duct entries.
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Originally Posted by wobbly
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