ESE's works engine tuner

[peewee]

Peewee, the short answer is: no, I didn't. But I suppose you'd rather have the long answer.

Let's keep it simple, Peewee. If a radius in any drawing is stated as, for example R20, then it means 20 mm, not some percentage of anything.
Moreover, the RSW drawings that you refer to, were the drawings that I could release at that time; they were not the RSA drawings.
Things have become even simpler since then: in the RSA cylinder the inner walls of the A-ports have one constant radius of 22,6 mm. If you wish to convert that to a percentage of the 54,5 mm RSA stroke (not the bore), be my guest.

There are some radii that I have quoted as being a certain percentage. They are the radius at the top edge of the main exhaust port (6% of the stroke) and the radius at the top edge of a radiused piston (8% of the stroke). But you cannot use these values just like that because they are not simply tangential at both ends, as you can see in the picture of the radiused piston below.
Attachment 314189

thnx frits. maybe i asked you about the exh window radius and thats where i remember it being a percentage of something. since ive got 82mm stroke and the inner wall at the bore is likely much longer than the rsa, i suspect the 22.6mm will be far to sharp of a radius. do you happen to recall the wall length at the bore like in my pic ? if i know that value then maybe i can calculate the same radius to my cylinder, unless you know a easier way as i was never a math expert. judging from the rsw drawing which may be far different than the rsa, i estimate the wall length at the bore to be about 36mm. does that sound about right ?

[F5 Dave]

Oh stop it. I want to ride my 300 again. Those effortless wheelies, torque laden pull out of slop.
Sigh. Being broken sucks. Gravity is a harsh mistress. Alcohol helps. And yes I know it's only 5 o'clock.

[peewee]

might as well sell that old thing. be a new 300 engine about this time next year. not sure what kind of internal changes it has as only exterior photos have been posted so far

[Flettner]

Neil, the man to talk to at BRC engineering is Riley Will: http://www.brcenginc.com/contact.html
Other possibilities are
Andrea degli Esposti of DEA, deaengineering@gmail.com
and
Francis Payart of FPE, f.p.e@wanadoo.fr.

You can give those guys my regards, and they may still help you .
Francis is even a kiwibiker forum member, so you could send him a PM, but I don't know how often he takes a look here.

24 mm from gudgeon pin center to tip sounds familiar. The Aprilia RSA and RSW had either 24 mm or 21 mm.
Try Asso and Vertex in Italy; both of them supplied the Aprilia racing pistons.

Thank you, phoned a guy in Canada, who said you need to contact a guy called "Wizzar" in Australia who said you need to contact Vertex NZ (where he gets his pistons) so I have an H size piston on the way, three weeks delivery! Now all I have to do is save up to pay for it

[husaberg]

thnx frits. maybe i asked you about the exh window radius and thats where i remember it being a percentage of something. since ive got 82mm stroke and the inner wall at the bore is likely much longer than the rsa, i suspect the 22.6mm will be far to sharp of a radius. do you happen to recall the wall length at the bore like in my pic ? if i know that value then maybe i can calculate the same radius to my cylinder, unless you know a easier way as i was never a math expert. judging from the rsw drawing which may be far different than the rsa, i estimate the wall length at the bore to be about 36mm. does that sound about right ?

RSA kind of looks a lot like a RSW other than the cooling and cylinder fixings.
Whilst here maybe detail changes in the Exhaust ports the radius look similar.



if you are wanting to replicate the Aprilia then get your welder out again some more and weld some fill onto the outside of the transfers so you can recreate the swooping organic cures of the transfer passages.
Then again if that pic is your twin (which I think it is)I doubt you have the room but, on the KTM single you do

[F5 Dave]

might as well sell that old thing. be a new 300 engine about this time next year. not sure what kind of internal changes it has as only exterior photos have been posted so far

My gg is an 07. SSS YZ forks, haven't ridden a better bike for me. Should be able to ride end of the year. Enjoy it while you can.

[wobbly]

The Aprilia drawings I have show the inner wall length as 37.2mm - but does not show the hand finished ball nose radius
on the intersection with the bore,thus I would estimate the length at 34.2,mm with an R3 radius on top of this at the duct entry.

[Frits Overmars]

since ive got 82mm stroke and the inner wall at the bore is likely much longer than the rsa, i suspect the 22.6mm will be far to sharp of a radius. do you happen to recall the wall length at the bore like in my pic ? if i know that value then maybe i can calculate the same radius to my cylinder, unless you know a easier way as i was never a math expert. judging from the rsw drawing which may be far different than the rsa, i estimate the wall length at the bore to be about 36mm. does that sound about right?

Let's do it the easy way, Peewee. The RSA has a 54,5 mm stroke and a transfer duct inner radius of 22,6 mm. Yours has a 82 mm stroke, so if you wish to maintain the RSA proportions, your radius should be 82/54,5 x 22,6 = 34 mm.
And if we assume an 'inside leg' of 36 mm for the RSA transfer duct (I haven't got the exact dimensions with me, but 36 mm sounds about right), then yours will need to be 82/54,5 x 36 = 54,2 mm.

[Frits Overmars]

phoned a guy in Canada, who said you need to contact a guy called "Wizzar" in Australia who said you need to contact Vertex NZ (where he gets his pistons) so I have an H size piston on the way, three weeks delivery! Now all I have to do is save up to pay for it

I forgot to tell you: don't mention Aprilia; it will make prices go up. I suppose you did ask Wobbly about all those 54 mm kart pistons?

[husaberg]

Thank you, phoned a guy in Canada, who said you need to contact a guy called "Wizzar" in Australia who said you need to contact Vertex NZ (where he gets his pistons) so I have an H size piston on the way, three weeks delivery! Now all I have to do is save up to pay for it

bump...........

Piston pour TM K7 e Vortex, TM 10050
not quite
Attachment 313974
http://www.superkart.it/index.php?ma...x&cPath=92_108


these I think might be 25mm
you will gain the rest offset boring the pin housing
http://www.ebay.com/itm/otk-tony-rac...-/252037482178


http://www.ebay.com/itm/go-kart-vert...item3a9f90b4bf

[seattle smitty]

But is this what Mr. Thiel was talking about (in the quote from Husaberg's post)? Presumably he would have known about these issues already, and taken appropriate measures to get the best outcome on cylinders to which he had originally done a lot of hand detailing. In other words, if a racer has a good but worn cylinder, and takes all the precautions you describe, is there any reason the re-plated cylinder won't work just as well as it did originally?

I persisted in this question because some of the top alky outboard racers report much faster wear of factory Nikasiled cylinders than the bikers see. Maybe this is a consequence of the different fuels . . .

[JanBros]

anyone looking for a cheap porting tool, I'd recommend looking at dental handpieces. thought already a while about buying something like this :

http://www.ebay.co.uk/itm/Dental-Lab...item58c3cc79d0

but as my dad is a retired dentist and now has plans to move to a smaller house, he's old aquipment needs to go and asked a 90° piece to try out (he still used them for his modelling trains , and still has loads and loads of burs/drills/polishing stones/... ).

it works with a compressor so I just used a preasure regulator and stuck the tube in it



could go to about 2bar before the original hose starts to blow up and gave it a try with a mill in it. the cut-out in the 2mm thick iron plate was done in about 2-3 minutes :



to show how easy it is to get in the transfer ports : this is in a 39mm moped cylinder :





when pushing to hard, the drill stops turning , and the bigger the diameter the less power you have before it stops. with the sanding stone in the picture, you won't be able to take away much material (only tried in on the iron casted cylinder, might be more of use in an aluminium cyl), but small diameter mills like in the first picture are realy usefull, and the sanding stones with bigger diameter can than be used to make the surface more even.

China-made dental pieces like this can be bougth very cheaply on ebay (for example http://www.ebay.co.uk/itm/5pcs-NSK-S...item3f3c52cfd8) . they probably won't last as long as much more expensive brand equipment, but at 10£ a piece worth a try. there are also pieces whith heads that can turn to give you different angles. you'd have to source the part to connect the hose to the piece but maybe the china-ebayer can supply it to. or you could go for an electric like in my first link.

[Frits Overmars]

I would not recommend dental hand pieces, Jan. In my experience they are too fragile for cylinder work. The bevel gears in particular won't survive very long.
I once got a box of used dental handpieces for free and used them to modify a 125 cc cylinder. When the cylinder was done, the box was empty: all five sets worn out.

What I will recommend, albeit in a sturdier form, is the swivel head. It's great; it will enable you to get to every imaginable spot.

[peewee]

keep your eyes on ebay. ive seen alot of used foredom stuff for cheap. the only piece i havent been able to find cheaply is the 90* but if you can buy everything else dirt cheap then full price for the 90* shouldnt break the bank

[Yow Ling]

keep your eyes on ebay. ive seen alot of used foredom stuff for cheap. the only piece i havent been able to find cheaply is the 90* but if you can buy everything else dirt cheap then full price for the 90* shouldnt break the bank

There is also Foredom stuff on Aliexpress, it is all counterfeit and rubbish. The only upside is if you order it you get your money back and can keep the motor flexshaft and toolholder, this process takes a little extra time.