ESE's works engine tuner

**peewee** · 14th January 2018, 20:16

how much nitro will a dirtbike tolerate

. the answer is easy. atleast 20% but how much more I just don't know . theres only one way to find out though. with just two or three more months of winter left I been getting ready for the riding season again. already I lowered the com ratio down to 12.5 and did some more carb work. ill make a new alumi fuel tank and ditch the fuel pump for a gravity system I think

**Flettner** · 14th January 2018, 20:27

Originally Posted by peewee

how much nitro will a dirtbike tolerate

. the answer is easy. atleast 20% but how much more I just don't know . theres only one way to find out though. with just two or three more months of winter left I been getting ready for the riding season again. already I lowered the com ratio down to 12.5 and did some more carb work. ill make a new alumi fuel tank and ditch the fuel pump for a gravity system I think

If some is good then more must be better!

**peewee** · 14th January 2018, 22:03

yes indeed. i probly wont go back to straight methanol. what i wish i had a fancy ign that could be programmed in the field or programed at home to hold a bunch maps in storage then test all of them .

**Frits Overmars** · 14th January 2018, 23:35

Originally Posted by peewee

frits i think you confused me for tjbw.

Yes I did. Sorry about that Peewee.

Originally Posted by Frits Overmars

the acquision by Aprilia of the old Guzzi works that turned out to be almost worthless

Originally Posted by Niels Abildgaard

Can we have the story why V2 Guzzis were worthless and V2 Ducatis are not?

No you can't, because that is not what I said Niels. I mentioned the almost worthless Guzzi works. Aprilia had hoped to be able to produce some of their models in the old Guzzi factory in Mandello, but the production facilities there turned out to be too old-fashioned to be of much value.
You might think, as did I, that it would have been easy enough to go over there and take a look at the available equipment before signing a contract, but apparently other factors played a role. Whenever money is wasted, there are always some people taking advantage of the situation. In Italy it has become an art...
Jan Thiel could tell us a story or two about Piovaticci, Minarelli, Garelli, Fantic, Sanvenero, Gilera, Rumi, and indeed Aprilia, and I witnessed more than one manager driving his Ferrari or Lamborghini away from the mess he left behind.

**mx2stroker** · 15th January 2018, 00:02

Hello folks, I believe some here can help me to find who sell Rotary Valve parts to Aprilia GP 125 engine ?

Like the disc, intake manifold, Rotary Shaft Assembly etc.

Gold if someone could give me a tip.

Regards: Andy

**Michael Moore** · 15th January 2018, 06:17

Walsh land speed racer Bantam

**breezy** · 15th January 2018, 08:37

Frits/wobby, if it were possible to maintain a higher pressure in the transfer ports on the 2 stroke engine greater than or equal to the pressure in the cylinder after combustion as the piston descends and the exhaust opens, would this not allow us to place transfer port widows into the cylinder at the same hight as the exhaust port or even higher?

**Magnus676** · 15th January 2018, 10:02

Hey guys,I've got a question regarding exhaust length for a drag bike.
I think a drag bike will work better with a shorter pipe in general.
My reasoning for this,is that a drag bike is only running for 1-2 min total,so the temperature will be lower than a road race bike.
Do any of you guys have build a pipe for a drag engine?
PS: Do you guys know a decent shop that does dynamic balancing?I want to balance my crank,but I want the shop to be in Europe if possible.

**Muhr** · 15th January 2018, 10:47

Originally Posted by Magnus676

Hey guys,I've got a question regarding exhaust length for a drag bike.
I think a drag bike will work better with a shorter pipe in general.
My reasoning for this,is that a drag bike is only running for 1-2 min total,so the temperature will be lower than a road race bike.
Do any of you guys have build a pipe for a drag engine?
PS: Do you guys know a decent shop that does dynamic balancing?I want to balance my crank,but I want the shop to be in Europe if possible.

Build a pipe for the EGT and RPM as you wish, try to use as thin sheet as you can and protect the header from the wind. Frits has posted a great crib sheet name FOS he has done.
Why dynamic balancing?

**F5 Dave** · 15th January 2018, 12:13

Surely for dynamic balancing to be of benefit then all the parameters need to be considered. So it should be done fully assembled, running, and mounted in the frame it will be used in.

I think we can see where I'm going with this. . .

**RomeuPT** · 15th January 2018, 12:37

Originally Posted by Pursang

A chunk of SS in the port might be a good thing.....or a disaster.
SS has thermal conductivity around half of steel and perhaps a 10th of cast alum.

Maybe it will absorb less heat during the exhaust flow and transfer less to the 'flow through' charge. (Win/Win)

Or....It might just heat up and up and transfer huge quantities of heat to the new charge (Lose/Deto/Lose)

Far too many factors to consider just at the moment.

The reference to the vacuum flask is for a purpose.
There are 3 factors to be combined for a Thermos to work, miss out on any one and all you have is a bottle.

Shiny surface to reflect heat transfer by radiation. (Like Wobbly's piston crowns).
Vacuum (or air) gaps to prevent transfer by convection. (or bubbles in foam or some ceramics)
Long, thin, pathways and materials to reduce conduction, (SS better than steel and alum. not as good as glass & some ceramics)

Do some experiments and report what happens. Might be the next 'Big Thing' in 2T technology.

Cheers, Daryl.

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Bike is off for the winter, no conclusion yet, before the spignot had been in thin mildsteel welded to the exhaust

**Niels Abildgaard** · 15th January 2018, 21:13

Originally Posted by Frits Overmars

Yes I did. Sorry about that Peewee.

No you can't, because that is not what I said Niels. I mentioned the almost worthless Guzzi works. Aprilia had hoped to be able to produce some of their models in the old Guzzi factory in Mandello, but the production facilities there turned out to be too old-fashioned to be of much value.
You might think, as did I, that it would have been easy enough to go over there and take a look at the available equipment before signing a contract, but apparently other factors played a role. Whenever money is wasted, there are always some people taking advantage of the situation. In Italy it has become an art...
Jan Thiel could tell us a story or two about Piovaticci, Minarelli, Garelli, Fantic, Sanvenero, Gilera, Rumi, and indeed Aprilia, and I witnessed more than one manager driving his Ferrari or Lamborghini away from the mess he left behind.

This sounds much more like my favourite industrial horror bedtime reading.

Italy is a real nice place.

If Jan Thiel put the stories on paper I buy first copy.Signed eventually.

**Frits Overmars** · 15th January 2018, 22:36

Originally Posted by breezy

Frits/wobby, if it were possible to maintain a higher pressure in the transfer ports on the 2 stroke engine greater than or equal to the pressure in the cylinder after combustion as the piston descends and the exhaust opens, would this not allow us to place transfer port widows into the cylinder at the same hight as the exhaust port or even higher?

Yes it would Breezy. I'd just like to know how you are going to achieve that kind of scavenging pressure, since the cylinder pressure at exhaust opening can be rather high: more than 11 bar in an Aprilia RSA.

Originally Posted by Niels Abildgaard

This sounds much more like my favourite industrial horror bedtime reading. Italy is a real nice place. If Jan Thiel put the stories on paper I buy first copy.Signed eventually.

Italy really is a nice place; I always love to go there. Lovely weather, good food, nice people, lots of small motorsport-minded enterprises willing to perform short-term jobs. And you'll find 'grey economy' anywhere; at least in Italy it's not so hush-hush and more openly accepted, so you can make use of it if you feel the need.

An example of the way things work in Italy: some non-Italian acquaintances of mine were taking part in an Italian race series. The officials there drove them crazy; regulations, if available in English at all, were translated badly, and often refered to other regulations that of course were not at hand. I advised them to not even try and argue with those officials, but instead have lunch with their superior and make sure everybody saw it. Somehow, the day after, all problems were gone...

As for Jan Thiel writing a book: it's not going to happen. We used to think about it; we would have done it together and my background as a technical editor would have come in handy, but for it to be profitable we would have to do it both in English and Italian or Spanish, which would have been just too much of a hassle.
Instead, Jan is now contributing to a couple of forums and if you were to collect all his posts, you'd have quite a book already.

**FastFred** · 16th January 2018, 06:24

Originally Posted by F5 Dave

Surely for dynamic balancing to be of benefit then all the parameters need to be considered. So it should be done fully assembled, running, and mounted in the frame it will be used in.

Yep, plus one. Time consuming but that is the only real way to achieve the best results.

**TZ350** · 16th January 2018, 08:12

Team ESE start off guessing at a suitable balance factor.
Then we try it in the bike and refine it by adding or taking a bit off the flywheels each time the engine is apart until we have something that shakes acceptably.
Dynamic balancing will only give you a carefully prepared crank based on a best guess for a BF which may work out to be right but will probably be wrong and need refining.