new improvement in the Jenvey Throttle body

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Portofino Norton's Garage

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Many of you know that Iwilson had at the time demonstrated how the channel in the throttle body that connected the two cylinders immediately downstream of the intake valves was a design error in an engine phased at 270 degrees.

Some of you, and I among them, had blocked it, interposing a pin configured in some way to replace the air supply pipe controlled by the solenoid valve for idle adjustment.

new improvement in the Jenvey Throttle body

The results had generally been excellent, very stable idle and no longer erratic, smooth operation, in short, a panacea. However, I was still left with the thought that those two blind semi-ducts, although there was no longer any passage for the gases, created a negative turbulence for the gases being sucked in, precisely in a point where there shouldn't be any.

Therefore I decided to block them completely, creating alu caps on the lathe, inserted with interference into the two holes, which I then blocked for further safety with two bolts which engage in the two lateral pipettes which were originally closed by rubber caps (which by the way they always got ruined due to the arduous working conditions).

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Nice to say, the road test confirmed that this is a further notable improvement in engine operation, it becomes even more fluid, very regular from 1800 rpm, quicker to rev up. Overall, a highly recommended change.
 
Portofino Norton's Garage said:
Mnohí z vás vedia, že Iwilson v tom čase demonštroval, že kanál v tele škrtiacej klapky, ktorý spájal dva valce bezprostredne za sacími ventilmi, bol konštrukčnou chybou motora fázovaného na 270 stupňov.

Niektorí z vás, a medzi nimi aj ja, sme to zablokovali vložením kolíka, ktorý bol nejakým spôsobom nakonfigurovaný na výmenu prívodného potrubia vzduchu ovládaného solenoidovým ventilom na nastavenie voľnobehu.

new improvement in the Jenvey Throttle body

Výsledky boli vo všeobecnosti vynikajúce, veľmi stabilný voľnobeh a už nie kolísavý, hladký chod, skrátka všeliek. Stále som však zostal pri myšlienke, že tie dva slepé polovody, hoci už tam nebol žiadny priechod pre plyny, vytvárajú negatívnu turbulenciu pre nasávané plyny, práve v mieste, kde by nemali byť žiadne .

Preto som sa rozhodol ich úplne zablokovať a na sústruhu som vytvoril hliníkové uzávery, vložené s presahom do dvoch otvorov, ktoré som potom pre ďalšiu bezpečnosť zablokoval dvoma skrutkami, ktoré zapadli do dvoch bočných pipiet, ktoré boli pôvodne uzavreté gumovými uzávermi (ktoré spôsob, akým sa vždy zničili kvôli náročným pracovným podmienkam).

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Je pekné povedať, že cestný test potvrdil, že ide o ďalšie výrazné zlepšenie chodu motora, motor sa stáva ešte plynulejším, veľmi pravidelným od 1800 otáčok za minútu, rýchlejšie sa zvyšuje. Celkovo veľmi odporúčaná zmena.
Click to expand...
Môžete napísať presné rozmery hliníkových kolíkov? Vymedzili ste medzeru medzi čapmi a sacím potrubím nejakou zmesou obmedzujúcou vôľu / Locktite ... /?
 
the duct is made by fusion therefore is not precise having a medium 8mm diameter, we used a 7,5mm diameter cap and the rest was covered by a liquid sealant.
Even without the bolts the caps are fixed forever there, the bolt was just a major safety.
Believe to me the difference against the simple closing the duct in the middle is sensible in the engine operations.
 
Portofino Norton's Garage said:
the duct is made by fusion therefore is not precise having a medium 8mm diameter, we used a 7,5mm diameter cap and the rest was covered by a liquid sealant.
Even without the bolts the caps are fixed forever there, the bolt was just a major safety.
Believe to me the difference against the simple closing the duct in the middle is sensible in the engine operations.
Click to expand...
Thank you very much, I will definitely implement it.
 
nice work
thanks for that
it just makes such an improvnment blocking the channel between throttle bodies off
 
Portofino Norton's Garage said:
Many of you know that Iwilson had at the time demonstrated how the channel in the throttle body that connected the two cylinders immediately downstream of the intake valves was a design error in an engine phased at 270 degrees.

Some of you, and I among them, had blocked it, interposing a pin configured in some way to replace the air supply pipe controlled by the solenoid valve for idle adjustment.

new improvement in the Jenvey Throttle body

The results had generally been excellent, very stable idle and no longer erratic, smooth operation, in short, a panacea. However, I was still left with the thought that those two blind semi-ducts, although there was no longer any passage for the gases, created a negative turbulence for the gases being sucked in, precisely in a point where there shouldn't be any.

Therefore I decided to block them completely, creating alu caps on the lathe, inserted with interference into the two holes, which I then blocked for further safety with two bolts which engage in the two lateral pipettes which were originally closed by rubber caps (which by the way they always got ruined due to the arduous working conditions).

new improvement in the Jenvey Throttle body[/url
]
[url=https://ibb.co/8gvtcn8]new improvement in the Jenvey Throttle body[/url
]
[url=https://ibb.co/6mfpV5n]new improvement in the Jenvey Throttle body

Nice to say, the road test confirmed that this is a further notable improvement in engine operation, it becomes even more fluid, very regular from 1800 rpm, quicker to rev up. Overall, a highly recommended change.
Click to expand...
Hello,

nice work but how do you fix the start of the cold engine because you have no idle engine to manage the revs in cold conditions?

Panetone
 
Panetone said:
Hello,

nice work but how do you fix the start of the cold engine because you have no idle engine to manage the revs in cold conditions?

Panetone
Click to expand...
While I undertstand that a being an Australian may mean I don't understand "cold" starts - the simple fact for me has been that there is nothing to fix.

You start the bike, the bike runs fine.
 
On my list of things to try is a plug which allows the normal air flow from the control valve but puts a baffle between the two sides so although it is still possible for air to flow from one side to the other the baffle significantly reduces it.
 
Gojuu said:
While I undertstand that a being an Australian may mean I don't understand "cold" starts - the simple fact for me has been that there is nothing to fix.

You start the bike, the bike runs fine.
Click to expand...
Hi,

Coldstart: Engine cold, teperature outside -2 degrees for example

I hope this explains
 
When I blocked mine off and it came time to start her up even in cold weather there was never a problem. What you had to do is once the engine fired ever so gently give the old girl a wee wee wee bit of throttle to keep her ticking over at a steady 1K to 1.2K only needed for ten or twenty seconds then just pull away. After around half a mile or so the engine is warm enough to tick over normally.
 
I just finished this project a couple of days ago. I lathed a plug to fit in the center of the efi manifold. I have kept the IAC mechanism in place for aesthetics for now. I was going to block of the small side ports like Portofino had done but was not sure if I trusted them plugs to stay in place. So I have left that for a future project.
My bike starts reasonably well cold. My shop is around between 5C -10C this time of year. I find if I engage the starter with the throttle closed then roll/open the throttle very slightly, it’ll fire up. I then manually hold the throttle open but have to do that for a couple of minutes. It’s still winter here so no road tests yet.
 

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Hi Panatone, as it might be supposed I live close to Portofino (Liguria, Italy) so we don't have so cold winter here. However it might happen but nothing that you can't solve keeping a bit of throttle open for half a minute.
But the advantages of the original modification suggested by Iwilson (mine in this thread was only a fine tuning) by far overtake this very minor issue.
 
TonyA said:
Hi Pantone , I use a throttle cruise control lock to keep the revs up when cold .
Click to expand...
^^^^What Tony suggests is what I've told other owners. The other option is to find an early Ducati throttle enricher that has the stop lock built in.
 
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