Dellorto PHF32 Accelerator Pumps

RCGBOB44 said:
Runs just fine with 145 jets and they are the original ones fitted to the bike when delivered from new.
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When did the factory fit 145 jets? I thought Jotas came with 118 jets. The previous owner put 135s in my bike. It was running way too rich.

Grant said:
Fuel composition has changed sine then.
Dyno runs prove 145s are not necessary these days.

125s or 130s are all that is required on a UK Jota spec bike.
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Dunno whether UK fuel is different to the stuff we get in Australia, but after a series of dyno runs on my Jota, we settled on 120.
 
Slater fitted 145s to the original Jota and the 3CE before that.
As 5 star leaded was recommended at that time the fuel composition has dramatically changed nowadays.

Not sure if 79 Jota onwards (when the factory adopted the name) wore 145s ex factory when in full UK Jota spec.
All I know is my 79 UK Jota had 145s but it was 3 years old when I bought it so who knows.


 
Mine has 145 jets and was one of the ones that had no air filter as standard. Just the empty air box. I have K&N filters on it these days. It runs very nicely. My inclination is if it aint broke don't fix it, but now I am wondering if it would run even better if I went down a few sizes on the main jet ?

Could save some fuel I guess which is never a bad thing.

Should I change the jets  ?
 
"Could save some fuel I guess which is never a bad thing"
If you ride around regularly at 3/4 to 4/4 throttle it might save you a bit of fuel, but I doubt it will save your licence.
 
TheWrongTrousers said:
Mine has 145 jets and was one of the ones that had no air filter as standard. Just the empty air box. I have K&N filters on it these days. It runs very nicely. My inclination is if it aint broke don't fix it, but now I am wondering if it would run even better if I went down a few sizes on the main jet ?

Could save some fuel I guess which is never a bad thing.

Should I change the jets  ?
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Very doubtful.  Don't think any bike originally concieved with filters left the factory without (except those intended for racing, such as the F500 or RGS TT1), just too much at stake concerning homologation laws.

More probably a "dealer special".  Many a dead end street was trodden back then...

As Grant has stated, 120-130 seems to work quite OK, but imho, it has nothing much to do with modern fuel compositions.

piet
 
Piet, I refer you to Falloon - The Laverda Twins and Triples bible 2007 edition. At page 98 he describes the 1000 Jota/80 distinguishing features from  frame number 6604 to 7269.  Inter alia:-

'...while some Jota's were also offered without an air filter, with correspondingly larger (145) main jet.'

My frame number is 7145. It has 145 main jets. Therefore, it seems possible that within those 665 bikes between those frame numbers, my bike was among a number of those 'offered without an air filter.'

Assuming Mr Falloon is correct, of course.
 
I think the pages are correctly numbered in his books...

Who removed the filters, who fitted the jets?  Most probably not the factory.  Dealers and importers all over the globe attempted all sorts of things to shift the buggers from the showroom floors.

I cannot find any reference to such practice in any of the factory literature...

piet
 
Ian Falloon is contactable and wrote his book using mainly factory published bulletins. There would be no harm in asking him to look that one up for you, if you so desired.
It is correct to state that the main jet will operate between 3/4 slide movement and 4/4, but everything you change will affect everything else, so an emulsion jet change will affect main jet at any opening the same goes for a needle change, remember that nothing gets turned on or off, and all is affected by the air volume and velocity passing through. recently I was Jetting a BSA 350 Gold star, which had had fitted a 420 overbore kit, and initial tests showed massive mid range weakness, this was rectified, which then showed massive, massive, massive weakness at idle and hence created a starting problem, so a change of needle ruined a perfect running idle circuit which was then  changed and guess what the mid range was then out a bit too. It is also true to say that an engine will run without even a main jet fitted! but for sure everything affects everything else, for those that bother to be on the dyno and getting it right, plug colour and seat of the pants may get you to a point but not all the way.

Can you (applies to everybody reading) restart your hot or warm triple without using the choke????

CLEM
 
Do you know what Clem ? - since balancing my carbs afresh and generally fiddling with the air screws, and fitting some long overdue new plugs I can start it while warm without the choke. I never used to be able to, but now it does start when warm and can idle down to about 500 rpm to boot. I am pretty much happy with that. After reading what you said about everything being linked up ( which makes a lot of sense) I am just going to leave well alone.
 
for me, being able to start the bike without choke when hot or warm, tells me that the low end settings of the carb are correct, but also as(as a secondary), it tells me that my carbs are still in sync, as does the steady and forever idle of about 750rpm, many triples need choke to start from hot or warm, which is wrong in my book, and many  (usually the same ones) will die if left to idle for more than about ten seconds, it infuriates me when waiting for traffic or lights etc, to hear all around you the riseing and falling of revs as riders "keep their bike going" that is for the warm up area of a race track not the Old Kent Road.
CLEM
 
CLEMTOG said:
it infuriates me when waiting for traffic or lights etc, to hear all around you the riseing and falling of revs as riders "keep their bike going" that is for the warm up area of a race track not the Old Kent Road.
CLEM
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Clem if I started to list the things that infuriate me about using the road, I might never stop.
 
CLEMTOG said:
it infuriates me when waiting for traffic or lights etc, to hear all around you the riseing and falling of revs as riders "keep their bike going" that is for the warm up area of a race track not the Old Kent Road.
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That was fun in Italy though ..... twenty scooters all waiting at the lights ..... half of them girls ...... and the cloud of smoke when the light turned green! Ahhhhhh ........ the memories!

It's not like that anymore .......
 
It was like that in Firenze a few years ago. Traffic lights at some big roundabout was like a motoGP starting grid of scooters. I could have dusted them all from the start but knew it was better not to as they knew the "racetrack" much better than me.
 
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