ESE's works engine tuner

[wobbly]

Occasionally the turbulent model is affected incorrectly by the combustion parameters being out of range ie the duration goes over 100* ( usually squish related ) and
it all goes wrong.
Send a pack to Neels and he will be able to see the issue and advise.

Re the blowdown question - with a single Ex port you are always fighting a lack of blowdown STA, and this is where the only way to balance the power capability's of the transfers
with the Ex is to run the numbers thru an analysis program.
In general it is usually possible to get alot more transfer STA by widening them all to the max, whilst keeping them low to help the blow numbers without jacking up the Ex timing excessively.
Ski engines generally aren't limited badly by close bore centers creating shit transfer ducts, so concentrating on the area can reap good results.

[adegnes]

Occasionally the turbulent model is affected incorrectly by the combustion parameters being out of range ie the duration goes over 100* ( usually squish related ) and
it all goes wrong.
Send a pack to Neels and he will be able to see the issue and advise.

Thanks, I'll do that!

[wax]

Occasionally the turbulent model is affected incorrectly by the combustion parameters being out of range ie the duration goes over 100* ( usually squish related ) and
it all goes wrong.
Send a pack to Neels and he will be able to see the issue and advise.

Re the blowdown question - with a single Ex port you are always fighting a lack of blowdown STA, and this is where the only way to balance the power capability's of the transfers
with the Ex is to run the numbers thru an analysis program.
In general it is usually possible to get alot more transfer STA by widening them all to the max, whilst keeping them low to help the blow numbers without jacking up the Ex timing excessively.
Ski engines generally aren't limited badly by close bore centers creating shit transfer ducts, so concentrating on the area can reap good results.

Thanks wobbly.
Yes we have shit transfer ducts

[jonny quest]

http://blog.motorcycle.com/2014/04/1...coming-june-8/

[marsheng]

I would go bigger in the main jet to get the mixture right in the middle and then go bigger on the air jet to lean out the top, with a recheck of the middle afterwards.

I've got today to play around with this, however, for a wide power band is this mixture not the best ?

Lean at the bottom, this means engine runs hotter, (less fuel cooling) exhaust is therefore hotter so pipe looks shorter and closer to optimal and by the same reasoning, richer at the top means more cooling and temperatures lower and so pipe seems longer ?

I may make more power with changes but a wide band is what I'm after or a 6 speed gearbox.

Cheers Wallace

[wobbly]

Completely opposite logic is needed - unless im reading you wrongly?.
Rich at the bottom to cool the pipe, making it appear longer for drive of slow corners, then lean at the top to get it to spin
up with the higher egt making the pipe shorter.

[marsheng]

Completely opposite logic is needed - unless im reading you wrongly?.
Rich at the bottom to cool the pipe, making it appear longer for drive of slow corners, then lean at the top to get it to spin
up with the higher egt making the pipe shorter.

You are correct, just as well I checked. Brain fade.

[husaberg]

AvGas in NZ is all LL100, this is low lead 100 octain.But the rating is defined differently in avaition.Its approx equiv to 100 "pump" gas, but has a lean rating of 100 and a rich rating of 130.
MNZ Appendix E defines avgas as max 112 MON amd max 108 RON.

Avgas, or any leaded "race" fuel reacts completely differently to unleaded pump gas.
In general terms the unleaded hates compression, but loves timing.Avgas is the opposite in that it makes more power up to the knock limit with more com.
Unleaded makes better power when run rich,avgas makes more the leaner you go.
Tuning in the old days with RS and TZ engines meant using lean mains and small powerjets ( 35 ) as turning off a big jet over the top would mean being too lean in the overev.
Nowdays the unleaded fuel runs rich at peak power, then uses a big powerjet ( 55) to create some heat in the pipe over the top.

Just to be clear.

[peewee]

My GG is just an open hole but small enough that probably doesn't affect power much but at kick over speeds means its no harder than my 200. This is super important to me when tired having stalled half way up some slippery single track.

Saw the bolt hole, what was the brand again? Pumpkin?

dont ask me to explain how it works because i havent a clue. i plan to plug it off

[peewee]

this should do the trick

[F5 Dave]

Ahh, so its an old Pumpkin, maybe before they were pumpkin coloured.

So a bit of extra blowdown in full open position but obviously with some loss esp at lower revs (smoother is a nice way of saying it). You'd obviously be better to block it or better yet push an insert mostly into it, & find more area in the main port or subs. . . .if you weren't dirt riding it. If you were, a thumb operated valve for starting & closed would be best for low down. Or just leave it, it'll have scads more power than most of us need for the dirt.

[peewee]

i figured it would be best to have the exh gas exit all at once rather than have the pressure drop slightly before the main port opens. ktm's logic isnt making sense to me

[F5 Dave]

Too much Weiner Schnitzel at KTM lunch cafeteria.

[TZ350]

Rob will forgive me for saying (i hope) that at times he is a little keen to try to many things.

Youthful over exuberance i guess.

Youthful over exuberance ..... too right, or something!!!

[husaberg]

Youthful over exuberance ..... too right, or something!!!

That bloody quote was over threes years ago.