ESE's works engine tuner

[bucketracer]

2-stroke crank mods http://vincentcrabtree.co.uk/RGV250CrankStroking.aspx

Some RS125 info http://www.bonavolta.ch/hobby/en/moto/rs125r.htm

Some practical carb setup stuff http://www.bonavolta.ch/hobby/en/moto/mainjets.htm

And some VJ23 pics...........

[koba]

That is gold.
Who cares about oilin' the turbo anyway.

[husaberg]

Some stuff I found a while back for fork conversions
Plus some materials stuff here (if you want to build say a new frame) quite a neat site http://www.engineersedge.com/manufacturing_menu.shtml

interestingly it says yellow brass (what ever that is?) is 5 times better as a thermal conductor as copper is.
I remember reading Rudge (along with others too) used to use Bronze heads pre war.
They (Rudge) had Radial 4 valves/cylinder engines 50 years before Honda.

[bucketracer]

What American F4 Bikes look like http://cgi.ebay.com/ebaymotors/Honda...Q5fmotorcycles

And F5 http://cgi.ebay.com/ebaymotors/Honda...Q5fmotorcycles

[wobbly]

Whats inside your head then.
KTM250 open kart engine for reference.
CNC toroidal,0.8mm squish,38M/Sec MSV 13.5:1 on pumpgas.

[F5 Dave]

kewl. so the insert has been machined into a std head or is that a VHM or similar to start with? Clearly moddified to be lower height. What is the insert material? Brass? Or chromated ally? Brass rings are often used to stave off Detonation, but I've never really known why aside from hardness of the metal, but its a bit mute as the piston is what gets hottest. [edit] surely the squish area where rings are used don't get that hot compared with the rest of the head?

See what you mean about MSV calcs, but presumably only if yer got a digi ign to compensate?

[husaberg]

Whats inside your head then.

Mainly fresh air in my head, As well as being plain my head is pretty empty as well.
The reason I posted it.,Is I believe TZ is using Copper?

But here is a Toridal head 1962 style villiers Starmaker Attached A TZ350/700 head for the nostalgic yes bronze incerts I think they are refered to as detonation rings now.Is that right?
A 1930 250 rfvc head sorry could find a bronze pic but it seams every man and his dog had a bronze head in the 30s though.
Also a link to Rudgehttp://big-diesel.blogspot.com/2008/...dary-bike.html

[TZ350]

Nope, not going over to the dark side. Just digging through the bits and bobs to see if we can find enough good parts to put a Honda 100 together for young Robert.

But I do have to say, at the last Mt Welly meet, young Will's new F5 Honda did sound like a Manx, it sounded real good for a 4 stroker, exciting even.

[TZ350]

here is a Toridal head 1962 style villiers StarmakerAttached and also a link to Rudgehttp://big-diesel.blogspot.com/2008/...dary-bike.html

Interesting that the Star Maker had a toridal head.

KTM250 open kart engine for reference. CNC toroidal,0.8mm squish,38M/Sec MSV 13.5:1 on pumpgas.

What material is the insert made from?

[husaberg]

Interesting that the Star Maker had a toridal head.

They stole it from diesels (real ones)they had trouble with it and went back to top Hat.They ditched the the twin carbs to

I am however begining to wonder weather you really need more cb100 parts?
But I will send them anyway Rob.

Did you consider the 100s/xr100/crf100 engine i have alitlle inside info on how to get a 6 speed in one. they are light by diesel standards.

Quote Originally Posted by TZ350 What material is the insert made from?

I will let Wobbly answer that one.

[husaberg]

Whats inside your head then.
KTM250 open kart engine for reference.
CNC toroidal,0.8mm squish,38M/Sec MSV 13.5:1 on pumpgas.

Hello Wobbly
Have you done any work or seen any trial/test results done with offsetting the toroidal head to the rear?

Ie to keep it at the cooler side of the cylinder as in the Suzuki Wolf amongst others.

I realise its probably moot in a liquid cooled engine.
But I will ask anyway.
Now that would be a challange to machine. CNC or not

[wobbly]

The Starmaker shape was stolen from diesel tech, but as it shrouded the squish from the main body of mixture in the chamber, it was doomed from the onset.
The material is aluminium bronze, I would use beryllium bronze if cost wasnt an issue, the stock head itself I machined away to suit the insert.
In this case we attack all the relevant issues involved, with small detail tricks.
The squish band has a very highly heat conductive bronze surface that runs cool and keeps the end gases from overheating and thus forming radicals that lead to thermal runaway - deto.
Bronze inserted "rings" only do 1/2 the job as they have a heat joint barrier no matter how well fitted they are.
The one piece insert is far stronger than plain aluminium in such a big bore, thus the water can be run much closer to the places its needed, in the squish area , and around the plug threads, reducing thermal hysteresis.
And lastly, the chamber only is coated with a clear ceramic heat reflective, that retains the high temp in the chamber as the combustion gases are expanding.
Creating more gas expansion is the holy grail to pushing the piston down harder , with less wasted heat into the water - on the other side of the insert.
Same with the piston - only the chamber area is coated, if you coat the whole piston, the heat reflective surface becomes hotter than the raw piston underneath, again this will create deto in he squish band area.

Offset chamber heads were patented by a dirty Doctor from EMC who sold the idea to Yamaha, that used it for one year on a TZ and in some industrial shitters, then dropped it.
It didnt work then, and wont work now.
As it means in effect that the once beautifully symetrical chamber of a 2T has a MSV of 60M/Sec on one side and virtually zero on the other,the end gases have no chance of getting out, overheat ,and cause deto real fast - bugger.
And if you move the plug over as well you have just created a bigger bore in one direction, again - dumb idea.
Never seen a fast 250G with a stock head - ever.

[husaberg]

Offset chamber heads were patented by a dirty Doctor from EMC

Doctor Joe.
I hear he got a whole MZ engine early in the piece to.Or so Walter reckonded anyway.
Suzuki probably didn't need to buy it as they already had there own MZ engine to copy.Thanks to Ernst Degner.

I am 90% sure my old Suzuki Wolf had a offset plug/offset squish band .I will have a look next time I am at my old mans. The old Wolf was a good handler square trail tyres and all.But All revs no action though.

[F5 Dave]

I've seen pics of desert racers with twin plugs (std plus one added near rear) to try to reduce spark lead & stave off deto on huge 500cc bores. I think they also machined the squish with more taper on ex side to reduce MSV at that point, although you would think that might have the effect of less cooling from a parallel squish. Either way extreme measures for big bores held wide open for hours on sand.

Ahh the selective coating is interesting. I've never thought of it used that way, just all over & that didn't make much sense.

[F5 Dave]

. . .
I am sure my old Suzuki Wolf had a offset head .I will have a look next time I am at me old mans. The old Wolf was a good handler square trail tyres and all.But All revs no action though.

Just an RGV250 head & that was for clearance & best rectified for power.