otis v11
New member
- Location
- New Zealand
What size main jets would a Jota motor run.Cheers
Jota jets
- Thread starter otis v11
- Start date
Rob
Hero member
- Location
- Midlands, UK
There is plenty of information on original factory spec in the Library - https://laverdaforum.com/resources/categories/technical.4/
You could also use the search facility for more up-to-date info - https://laverdaforum.com/threads/180-jota-jetting-for-modern-fuels.80546/
You could also use the search facility for more up-to-date info - https://laverdaforum.com/threads/180-jota-jetting-for-modern-fuels.80546/
- Location
- Calgary, Alberta, Canada
before you attack the carbs, get the cam timing dialed in accurately, set the valve clearances accurately, and get your ignition and ignition timing sorted, preferably with something other than the antique stock ignition.
Main jet is last after you sort the other stuff in the carbs. Choke plungers properly adjusted and fully sealing? Intake rubbers sealed and not cracked or leaking? New needles, K1, start at middle notch. Needle jet AB265, new, not worn oval? Idle mixture screws still have there little O rings and not perished or missing. How badly are the slides worn, and what slides are in there at present. Slide bores in the carb bodies still OK or worn out? Slide heights balanced? Accelerator pump diaphragms still flexible and sealing, or stiff and cracked?
etc..
main jets only really affect 2/3 - 3/4 throttle up to wide open. They will be smaller than you might expect. The "good old days" of stuffing in 165 mains are long gone for any sort of decent running. Also, what exhaust and air intake? You will likely end up somewhere between 122's and 145's, max. Just my opinions of course.
Main jet is last after you sort the other stuff in the carbs. Choke plungers properly adjusted and fully sealing? Intake rubbers sealed and not cracked or leaking? New needles, K1, start at middle notch. Needle jet AB265, new, not worn oval? Idle mixture screws still have there little O rings and not perished or missing. How badly are the slides worn, and what slides are in there at present. Slide bores in the carb bodies still OK or worn out? Slide heights balanced? Accelerator pump diaphragms still flexible and sealing, or stiff and cracked?
etc..
main jets only really affect 2/3 - 3/4 throttle up to wide open. They will be smaller than you might expect. The "good old days" of stuffing in 165 mains are long gone for any sort of decent running. Also, what exhaust and air intake? You will likely end up somewhere between 122's and 145's, max. Just my opinions of course.
hooksey
Hero member
- Location
- Vic , Australia
Anywhere between 125-145 Ballpark............each motor can be very different!
Take a hand full of Jets to your local Dyno man and run her up to check A/F for piece of mind
chrisk
Hero member
- Location
- Brisbane, Australia
can do you a good deal on about 33/3'rd quantity of 145 ( 1,45m/m ) mains.... or my custom soldered up and redrilled to 118-120, or the even better marked 128 drilled to silly size... true... supplied to me by a lunatic at known Laverda ( oz ) dealer, that was fun sorting that out...
As the lads point out, not so much what everyone uses, matter of state of setup/modifications. Electronic proper advance curve(s), guide. 180 motor; PHF carbs, 125 mains, 55 pilot, K1@middle clip, pilot fuel screw 1 and 3/4 out from stop ( careful ) choke plunger 3 m/m free play, however most of all 18m/m on the float bowl, this has precedence above all else. HTH j ***( Pumpers off, clean tank and fuel lines, air cleaner free breathing type, stubs not leaking or cracked, new fuel, then sync the carbs.... lot of work for a young man, almost too much for an old man, wry smile here.
Way over rich with low comp pistons and A12 cams.
We still don't know what's in that Jota.
There's a happy punter in the US somewhere with an orange and silver "Jota" with low comp pistons and A12 cams. He finds that it performs well for an old bike. (there's likely quite a few of those around)
Paul
Not suggesting 145, i have more than twenty removed from owners rides with PHF, view second paragraph, for recommended place to start with proper electronic ignition.... Ridden a stock 3c, would not bother truth be told, like riding a Duck Darma... fall asleep while riding them... as it may please the riders of similar performance setups...j
mauricejota7604
Hero member
- Location
- Victoria Australia
Quite true here’s my low tune Jota, well it is orange and it has a Jota sticker
In fact I am going to give the poor cousin RGA a bike plug, a great long distance bike, comfortable and easy to ride with higher bars.
Pity it’s so ugly!
Attachments
Get a twin.Quite true here’s my low tune Jota, well it is orange and it has a Jota sticker
In fact I am going to give the poor cousin RGA a bike plug, a great long distance bike, comfortable and easy to ride with higher bars.
Pity it’s so ugly!
Paul
mauricejota7604
Hero member
- Location
- Victoria Australia
Ive got two of them.