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del lorto's on a 750 sport

Posted: Tue May 03, 2016 5:59 pm
by lodola235
Hi, I've gbought an750 of 90 in reasonable state,
my problem is it doesn't start cold unless i use start pilot, i've heard that the Weber carb is an pain in the ass
I still have two brand new del lorto's with accelerator pumps, but they are 32 mm.
my question is can I bore them to 36 on my lathe or will i destroy them doing that,
and at what angle can i mount them on my motor without having problems with the float level or do i have to modify if the are too much at angle ?
can't wait to ride my duc? going troug the paper issues first

thanks in advance
Bart

Re: del lorto's on a 750 sport

Posted: Tue May 03, 2016 9:20 pm
by Mc tool
Its not unusual to need the cold start device to start the engine when cold . Dunno about boring 4mm out of a carb , I guess the 1st thing to do would be to measure the slide diameter as it that's not at least 38mm then boring to 36mm is out of the question , and then there are other things to consider , personally I would get a pair of 36mm carbs if that's what you want . Having said that I would 1st give the weber a good clean out and see how it goes . There is a heap of info available here on how to modify/tune the weber and get it behaving a bit better . I think its worth giving the weber a decent try as there is a lot of FAB to get other carbs fitted ( manifolds ) and tuned .

Re: del lorto's on a 750 sport

Posted: Wed May 04, 2016 8:23 am
by Derek
The Dell Orto PHF series covers choke sizes from 30mm to 36mm and all use the same components including the slides. So theoretically, yes you could bore them. I wouldn't want destroy a pair of good carbs though if I got it wrong :shock:
I don't know how far you can tilt them. I'd think about 45ยบ would be the max.

Re: del lorto's on a 750 sport

Posted: Wed May 04, 2016 8:23 pm
by Mc tool
Derek wrote:The Dell Orto PHF series covers choke sizes from 30mm to 36mm and all use the same components including the slides.
Ahh , I didn't know that , stands to reason then that there wouldn't be any air/fuel passages in the carb body that are in the way ............maybe :)

Re: del lorto's on a 750 sport

Posted: Sat May 21, 2016 5:34 am
by ducinthebay
The 32's will run just fine. The only place you will miss out a bit is in the top end. It will carburate just fine at idle and mid range. I doubt you will be pinning the redline on a 25 year old bike anyway. Think of it as a rev limiter of sorts.

Here is a link to a tuning guide for the Dellorto's.
http://danskkartingcenter.dk/dellorto_m ... _guide.pdf
Looks like 40 degrees is max tilt on the Dells.

Manifolds can still be had from Mallosi, and run about $150. Or you can salvage some from a Pantah motor. Get new o-rings if you get some used ones, and don't be tempted to use some RTV to seal them to the head, as new fuels will degrade the RTV in a year or so and you will be plagued with air leaks that will make tuning a pain in the ass. (a nugget of knowledge gifted to me from a previous owner)

Cheers, Phil

Re: del lorto's on a 750 sport

Posted: Sat May 28, 2016 6:13 pm
by lodola235
some news on my beautifull duc

I've bought an set of mikuni's with the acording manifolds and K&N's,
duc starts magnificent, runs better seems a bit too rich, but i' haven't let the carbs syncronised yet, so expect to be better afther, all that in order to have more time to decide if an reversed head and dellortho's or just the carbs .
by the way still busy with the registrating problems so i have some time.
hope it will be an relaible bike i ride sporty but don't race

Re: del lorto's on a 750 sport

Posted: Tue Jun 07, 2016 11:34 pm
by ducinthebay
That works too. A fairly cheap and reliable solution, that almost always works well.

Phil

Re: del lorto's on a 750 sport

Posted: Tue Jun 14, 2016 7:22 pm
by lodola235
Hi,
the battery of my sport 750 doesn't work any more ; so i've looked around, and
an lion ion is about 395 (!!) euro's and weights 1.2 kg (!!!!!!) with the high place it has, weight is important
an gel battery is 86 euro and weights 4.5 kgrs
and care free is 101 euro and weights 7 kgrs
and an 'normal' battery 75 euro and 5 kgrs,
any one has an gel and is he ok with ? that seems the reasonable solution for me : no leakage and resonable price
plus i've read that some people mount an modern voltage regulator,does that make any sense ?

Re: del lorto's on a 750 sport

Posted: Tue Jun 14, 2016 7:22 pm
by lodola235
Hi,
the battery of my sport 750 doesn't work any more ; so i've looked around, and
an lion ion is about 395 (!!) euro's and weights 1.2 kg (!!!!!!) with the high place it has, weight is important
an gel battery is 86 euro and weights 4.5 kgrs
and care free is 101 euro and weights 7 kgrs
and an 'normal' battery 75 euro and 5 kgrs,
any one has an gel and is he ok with ? that seems the reasonable solution for me : no leakage and resonable price
plus i've read that some people mount an modern voltage regulator,does that make any sense ?