ESE's works engine tuner

[wobbly]

I can get Devcon B liquid out of Australia ( made there ) for near 1/2 what retailers sell it for here.
The syringe with that would be super clean and tidy even if it is " disposable".
Come to think about it , the liquid version would be easily dispensed with a heavy duty plastic syringe I imagine.

[pirkka1]

I want to add some epoxy to the front B port wall to make it perpendicular to the bore like the Aprilia scavenging regime.
So I have taken silicon port cores , and will cut these to use as forms.
The only epoxy I have ever used is JB Weld or Devcon F putty. Both are way to viscous to be able to "pour " it down between the duct wall and the form wall - even if the casting
is sat in an oven for a while , they will soften but go off with the heat before filling the vertical void completely.
Any suggestions on what to use in this scenario that WONT fall out.

Greetings from Finland, first post here.
I thought i'd share my experiences. Husqvarna sm 125 7 transfer converted to 5 transfers. I used Bison Metal epoxy(looks like its only available in europe) but it was very easy to pour when heated a little bit.
has been holding up for three years of occasional racing without even trying to come off.

[wobbly]

Thanks guys , I have some Devcon B coming from OZ and i got some big plastic syringes for $4.00 , perfect.
Just have to mask the port and duct entry then use a bubble level on the cylinder for the liquid to form a dead flat new wall - easy.

[Tim Ey]

Greetings from Finland, first post here.
I thought i'd share my experiences. Husqvarna sm 125 7 transfer converted to 5 transfers.

...and? Did the changing of the porting scheme do you good? Measurable improvement?

[wobbly]

Well as an example of what can be done, here is a 4DP20 Kit cylinder that is close to rocking horse shit and moon beam cost ( 500,000Yen ) that has 7 transfers and the
best pipe money can buy - the latest Jolly/JL for a 4TW.
Against a 3XV - TZR250 road bike cylinder with a PV that closes off all 3 Exhausts and its 5 transfers ported as per the RSA scavenging scheme , plus of course my 75% duct exit area ( stock 3XV ).

They both achieve exactly what the port STA numbers say is possible , but are of course hamstrung inherently by Yamaha's obsession with the short 50.7 stroke and
wanting insane amounts of transfer port duct wall area.
They won nothing for 10 years with the 3YL/4DP due to this shortsightedness till 2000 with the NX5 that was square and won the 250GP title easily with Olivier Jaques.

You can also see that Yamaha were obsessed with huge reeds ,Im thinking of fitting RS125 VeeForce that are smaller in curtain area , but make more power in the sim - funny that.
Also allows me to make the manifolds the same , stock , one is 20mm long , the other is 40mm - plain dumb.
Might even go Lectron with the Yamaha solenoid powerjets as this allows both inlets to be dead straight, as the Mikuni's cant be tipped up as much - worth 1.5 Hp in a SKUSA CR125.

[pirkka1]

...and? Did the changing of the porting scheme do you good? Measurable improvement?

Kinda testing in progress and a really bad test at that.I changed too many things at once. the stock cylinder only has 117 transfer and 177exh timing. mine were raised to 130/200 with the 5 transfer mod.
With 36mm pwk,modified stock inlet and factory CR cross pipe it made 28.2whp at 12000rpm with too low egt. driving it power fell off only after 13k and ran 13.5k when doing top speed.

my friend has pretty much the same setup with small differences like 38mm TMX, Vforce3 and Rino tuning exhaust, about same timings and ported by me, but still 7 transfers. and it 27.5whp and less low end and over rev. both bikes have ignitech igniton.

Cant really say the 5 transfer mod is making the difference due to different setups. next plan is making a new exhaust to make some of the port area i have and see how well(or badly) the scavenging holds up.

[F5 Dave]

That seems somewhat confused. What are you trying to build? At those revs, not an mx bike, some sort of Motatd hybrid? Enormous change in timing and presumably an mx pipe fitted still.

[41juergen]

Well as an example of what can be done, here is a 4DP20 Kit cylinder that is close to rocking horse shit and moon beam cost ( 500,000Yen ) that has 7 transfers and the
best pipe money can buy - the latest Jolly/JL for a 4TW.
Against a 3XV - TZR250 road bike cylinder with a PV that closes off all 3 Exhausts and its 5 transfers ported as per the RSA scavenging scheme , plus of course my 75% duct exit area ( stock 3XV ).

They both achieve exactly what the port STA numbers say is possible , but are of course hamstrung inherently by Yamaha's obsession with the short 50.7 stroke and
wanting insane amounts of transfer port duct wall area.
They won nothing for 10 years with the 3YL/4DP due to this shortsightedness till 2000 with the NX5 that was square and won the 250GP title easily with Olivier Jaques.

You can also see that Yamaha were obsessed with huge reeds ,Im thinking of fitting RS125 VeeForce that are smaller in curtain area , but make more power in the sim - funny that.
Also allows me to make the manifolds the same , stock , one is 20mm long , the other is 40mm - plain dumb.
Might even go Lectron with the Yamaha solenoid powerjets as this allows both inlets to be dead straight, as the Mikuni's cant be tipped up as much - worth 1.5 Hp in a SKUSA CR125.

Not more to say...

[Orengo98]

A bit of a stupid question maybe, but...

I'm currently working on a bike, and I need to buy the spark plugs for it. The manual recommends a Lodge R47-49, Champion L58R or a Bosch W290 - t16 and the bike arrived to me with a Champion L-3G.

The thing is that all of those are short reach plugs, and the cylinder head seems to have been designed for a long reach spark plug. If I install any of those plugs, the spark plug remains "hidden" inside the thread hole of the cylinder head. And that doesn't look good to me.



Would you agree it's better to ignore the manual and fit a long reach plug? If I install a long reach plug with a washer, the plug is flush with the combustion chamber roof.

Thanks in advance!

[Frits Overmars]

I'm currently working on a bike, and I need to buy the spark plugs for it. The manual recommends a Lodge R47-49, Champion L58R or a Bosch W290 - t16 and the bike arrived to me with a Champion L-3G.
The thing is that all of those are short reach plugs, and the cylinder head seems to have been designed for a long reach spark plug. If I install any of those plugs, the spark plug remains "hidden" inside the thread hole of the cylinder head. And that doesn't look good to me.

Would you agree it's better to ignore the manual and fit a long reach plug? If I install a long reach plug with a washer, the plug is flush with the combustion chamber roof.

A Bultaco head, isn't it? All Bultacos I've worked on had long reach spark plugs so I wonder what type yours is.
Anyway, never fit a short reach plug in a long reach head or vice versa. And if your head was modified from a short to a long reach plug, chances are that it was not the only modification, so you may forget about the manual in this respect.

[pirkka1]

That seems somewhat confused. What are you trying to build? At those revs, not an mx bike, some sort of Motatd hybrid? Enormous change in timing and presumably an mx pipe fitted still.

the stock timings are for 11kw regulations. the motocross version of the bike has typical 128/190 timings. Im just tuning it fun and seeing how much power i can get out of it.
the mx pipe is just what i had laying around, i know it need a better pipe.

[F5 Dave]

Oh. So it's road legal base. Didn't understand that as we don't have such draconian license laws. And you mentioned racing somewhere I think.

You could ride a full power RGV250 when they came out. That got dialled back to power to weight so a restricted 660 Triple is OK or a full (lack of) power 250 4 stroke.

Been a while since I was concerned of such things.

Heck my GG300 came with a spare road legal pipe. I fitted it for a dirt ride as it looked pretty much identical except that it hadn't been munched on a rock step. And it was matt black not Nickel.

It ran like a 3 legged cow. Turns out there was a Cat buried in the depths of the dwell section.

[diesel pig]

Well as an example of what can be done, here is a 4DP20 Kit cylinder that is close to rocking horse shit and moon beam cost ( 500,000Yen ) that has 7 transfers and the
best pipe money can buy - the latest Jolly/JL for a 4TW.
Against a 3XV - TZR250 road bike cylinder with a PV that closes off all 3 Exhausts and its 5 transfers ported as per the RSA scavenging scheme , plus of course my 75% duct exit area ( stock 3XV ).

Are the 3XV cylinders so much better than the 3MA cylinders. Would the 3XV cylinders still be better than the 3MA cylinders after they are ported? Just trying to work out what cylinder to go for a project.

[wobbly]

I have not even seen inside a 3MA so have absolutely no idea about power potential.
Post a bunch of pics on here.
Baseline for the 3XV is the small duct exit , PV closes all the 3 Exhausts , the narrow 14mm boost , tiny Aux that can be made huge and triangular , plus of course only 5 port and bolts straight on.
SP is NFG

[41juergen]

The 3MA10 cylinders from the MJ 1990 3MA3 also have low timings (192/126), but a wider C-port and a more rectangular A-port what makes it difficult to get the triangle shape of the aux export and so the required blowdown..