Dellorto problem...

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saraceno59
Cucciolo - the Lil Pup
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Dellorto problem...

Post by saraceno59 »

Hi guys, on my gt there are two beautiful dellorto carbs and i have an issue at the back cylinder one. As you can see at the picture, the neck is twisted and the carb is almost touching the frame, where the regulator is mounted. All the adjustment screws are behind the frame and its difficult to adjust. I see on E-bay various types of necks, but i am not sure to choose the right one, maybe some people here can help me with that. The other problem is that i opened the carb today to have a look and clean it by the way and i found the rear long thing of the picture (i do not know how its called in English) broken. Is there a replacement for that also?
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1973 GT750, 2000 SS750, 1996 Yamaha tenere 660, 1980 Yamaha LB50
saraceno59
Cucciolo - the Lil Pup
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Re: Dellorto problem...

Post by saraceno59 »

here are more photos.
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3.jpg
1973 GT750, 2000 SS750, 1996 Yamaha tenere 660, 1980 Yamaha LB50
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BevHevSteve
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Re: Dellorto problem...

Post by BevHevSteve »

That is a starter jet and we have them in stock for you

https://store.bevelheaven.com/carb-fuel ... ous-sizes/
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Steve Allen (925)798-BEVL[2385] Ride'm, Don't Hide'm
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saraceno59
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Re: Dellorto problem...

Post by saraceno59 »

Thats good Steve, what about the manifold problem, do you have a solution for that as well?
1973 GT750, 2000 SS750, 1996 Yamaha tenere 660, 1980 Yamaha LB50
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BevHevSteve
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Re: Dellorto problem...

Post by BevHevSteve »

that is how they are.....
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Ducati/Euro Spares -> https://Store.BevelHeaven.com
saraceno59
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Re: Dellorto problem...

Post by saraceno59 »

I see, how do you get the back carb tuned though?
1973 GT750, 2000 SS750, 1996 Yamaha tenere 660, 1980 Yamaha LB50
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BevHevSteve
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Re: Dellorto problem...

Post by BevHevSteve »

fingers to turn the idle screw. might need to rotate the carb a bit to do so
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Steve Allen (925)798-BEVL[2385] Ride'm, Don't Hide'm
Ducati/Euro Spares -> https://Store.BevelHeaven.com
saraceno59
Cucciolo - the Lil Pup
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Re: Dellorto problem...

Post by saraceno59 »

Thanks for your information Steve, i owe you a mythos in some Greek beach bar next time you come!!
1973 GT750, 2000 SS750, 1996 Yamaha tenere 660, 1980 Yamaha LB50
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geodoc
750 GT
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Re: Dellorto problem...

Post by geodoc »

If you have the "straight" manifold as found on the 750 Sport (I think). Does that give you a straighter shot at the idle and slide stop adjusters?
saraceno59 wrote:Thats good Steve, what about the manifold problem, do you have a solution for that as well?
saraceno59
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Re: Dellorto problem...

Post by saraceno59 »

Probably yes, for now i cannot even put my fingers in there. if i had a couple of centimeters would be enough.
1973 GT750, 2000 SS750, 1996 Yamaha tenere 660, 1980 Yamaha LB50
Spagjet
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Re: Dellorto problem...

Post by Spagjet »

the back carby on my GTS used to have a manifold that must have had the same problem, someone had "cut it and shut it" (i.e. cut a peice the shape of a skinny bit of pie out of the outside of the bend of the inlet manifold, close the resulting gap and then get someone with an aluminium T.I.G. to weld it back up again. It never caused me the slightest problem and the carby was an inch from the frame tube. I could set it vertical and the fuel bowl was still a few mm from touching. That would bug me if the carby was on an angle. You would think that would have to have a negative impact on the float level.
I ended up swapping those 32mm Dellortos and manifolds for a set of 36mm Dellortos and manifolds, the 36mm manifolds had never been tampered with but the back carby still could be set vertical, the end of my Ram-flo air filter just sat up a bit further and stuck out the side of the bike a bit further, I had to cut the front sidecover mount off to have enough room for it. There must be a lot of different manifolds when you think about all the different size carbies, stud widths, etc so I reckon the easiest and cheapest way would be the "cut and shut". You might have to clean up the inside of the manifold a little bit with a porting tool or something tomake it smooth. You can't see it once it's done and installed as it's on the inside of the bike but you can definitely see the carby sitting way to close to the frame tube every time you look at it. That would drive me mad...
machten
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Re: Dellorto problem...

Post by machten »

Geodoc is correct in that if you can find a 750 Sport rear manifold it is an elegant solution and makes rear carb tuning much easier. Here's my GT's rear Dellorto with such a manifold. Unfortunately, they seem to be hard to find.

Image

Kev
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Re: Dellorto problem...

Post by Spagjet »

I want to put sidecovers on my GTS (it's never had any in the 25 years I've had it but I got a good set with the GT I bought)(my GTS actually believe it or not had the front few inches of the sidecovers chopped off and stuck in the notch in the tank at the back of the knee dent with about 2 inches of bog, there was over an inch of bog in the whole knee dent. Still can't get over that "custom touch"), so I am going to have to make my rear carby sit a lot further in than it does now to make it work. I think I've found a straight manifold, haven't seen it yet so my fingers are crossed that it's a 36mm one. I have always thought the 36mm carbies on my GTS were originally off a 750Sport. Does that sound right? You say a 750S rear manifold is the way to go but you can't tell from your photo if that's a 36mm carby or not. Is it?

I got the 36mm manifolds with the 36mm carbies but they are both curved ones which is what it making me wonder. Do they come in both straight and curved?

If they were 32mm manifolds I would probably do the 'ol cut and shut but 36mm is just too rare to be chopping in to them. Can't see me doing it, anyway, might want to go back to carby in the breeze one day...
machten
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Re: Dellorto problem...

Post by machten »

As far as I know, Ducati didn't use 36mm dellortos until the Pantah (but my knowledge of the rubber bands could be written on a fingernail :? ). Certainly the 750 Sport has 32mm PHF AS/AD.

My pick above is of a PHF32 AS on a '73 750 GT.

Kev
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Re: Dellorto problem...

Post by Spagjet »

I chased after the manifold I mentioned yesterday and asked a few questions and found out that there is only 32 and 40mm manifolds. 36mm carbies go on the same manifold as 32's as it turns out. I can't remember why I didn't keep my original manifolds when I did the swap deal for the 36's but there was a reason.

I was never 100% sure my 36's were off a 750Sport, it's just what I got told, maybe I misheard. I believe the alloy spoked rim Borranis I swapped my chrome steel Borranis for years ago are off a 750S but I could be labouring under a misapprehension there too. Anyone know for sure if alloy Borranis are Sport wheels?

Thanks Kev for the info about the 32's on the Sports. It looks like pretty much all bevels came with the 32's stock. They are lovely little things, I had to really argue with myself about parting with the original ones off my GTS, I was very attached to them. It was a VERY big stuff around getting the 36's set up right but I definitely don't regret it. they have been trouble free fro years and there was an instantly noticeable difference in power.

Wonder why they went bigger with the carbs on a smaller capacity bike (Pantah)?

It just occured to me that there are belt-drive parts on my Bevel. Hmmm.............
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