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Discussion Starter #4
WoW! where did you get Dollerto's for your Bonnie? I had Dollerto's on my 69 VW Bug.
Dellortos are quite widely available in Europe, these carbs are used as stock with Motoguzzi, BMW, Laverda, Husaberg, Husqvarna, KTM and Ducati. They are available 34, 36, 38, 40 and 41mm. Theys are also equipped with accelerator pump.

Advantage?
Advantage against what? Against stock ones it is the same as with any bigger carb (Keihin FCR, Mikuni TMR).
I think you mean against Mikunis and Keihins. Fact is that these carbs have been manufactured in big numbers through the years because they have been original equipments in so many bikes. Keihin FCR;s and Mikuni TMR;s will never ever reach even 20% of the production numbers of these Dellorto;s (even added together).
That affects to the price. I can get 3 sets of these (PHM 41mm) with the price of one set of Keihin FCR39;s.
I would rather have Keihins, I think they are better and more modern ( with roller slides etc ). However, these will do the same work and give more or less the same power with one third of price...
 

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Dellorto pumpers

guys, anecdotal evidence from me this time, just my tuppence worth.

I fitted a set of those 38mm Dellorto's to a bmw r100r, original fitment being cv type Bing carb's. The Dellorto's were standard fitment to the r90s, which has different inlet manifolds, but I made a set up and just plopped the Dellorto's on.

It was a different bike, went like the clappers. You opened the throttle in 4th gear to overtake and the bike would GO, not just think about it like with the Bings.

I found the only downside was a heavy throttle action, because of the effort required to operate the pumps off the slides. I don't know how this would translate on the dyno, but there was no question the Dellorto, in the beemer's case, was a far better carb than the Bing.
 

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Discussion Starter #7
good, now let's see you tune them, sync them properly, and post a dyno run with some quantifiable results.
Should not be a problem. I have done it previously with Dellorto to one Ducati SS (bigger PHM40;s instead of single DRLA), One Honda XL500, one Honda 600 Dominator and One Husaberg ( bigger pump carb instead of stock non pump type one). There is nothing strange with it and I have access to all needles, jets and slides for tuning.

Dyno session will take some time, I still wait for bigger valves, otherwise head is ready.

I need 4mm bigger valves, please somebody tell me where to get ones, I have been waiting for them from Kibblewhite for months!!!
 

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I think they will make better hp then stock carbs but not as much as flat slides .Most times you get what you pay for .I think a flow bench and a dyno would tell you that.
4mm os valves,for someome that wants to save money is going to be pricey you will have to but some way bigger valve seats in they will be about touching each other.I am not sure i would want that big of valve on the street.Why would you want them with that small of carb anyway? 1 or 2mm os will take more air then those carbs will flow.
 

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Discussion Starter #9
I think they will make better hp then stock carbs but not as much as flat slides .Most times you get what you pay for .I think a flow bench and a dyno would tell you that.
4mm os valves,for someome that wants to save money is going to be pricey you will have to but some way bigger valve seats in they will be about touching each other.I am not sure i would want that big of valve on the street.Why would you want them with that small of carb anyway? 1 or 2mm os will take more air then those carbs will flow.
Hi Mike,

I was expecting you to come in. Thanks for response.

1. Dellortos: You are right, I wrote that I would rather have Keihins, they are the best. I have worked quite a lot with them ( Yamaha WR250, WR450, KTM250EXC)

2. Big valves: My head grinder wants to do it that way even with stock seats (seat width is almost the same as valve width). It is for controlling the flow in chamber, not to make hole bigger. I know already that channel before it is split to two is made smaller than stock. It has also be risen as high without braking through as possible, floor has been filled a lot. I will not compromise, he is working for AMA and MOTOGP teams, salary is coming from Japan factory. Only reason he is doing this is long time friendship. We will see, I trust him.

3. If you remember I will keep stock bore, with Wiseco high compression pistons. I need less carb than your big bore.

I have always done things differently. Mostly it have worked maybe because of my relationship for some real world class professionals.

Maybe this time I will fail...or not. We will see. I am maybe that propeller hat fellow.
 

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well all i can tell you a 2mm over intake valve is about the same size as the out side DIA. of a stock valve seat .A 4mm intake will be hanging over the seat by 1 mm on each side.I know this cause i had my intake seats replaced.You might want to ask him if he is aware of that.
 

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Well MONTTU whether you come out making more or less horsepower than others or not, I think it's very cool that you are trying an alternative, and I appreciate you posting the info. I will be very interested to see the results, I'm sure everyone wishes you well with your project, I certainly do.
 

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Discussion Starter #12
well all i can tell you a 2mm over intake valve is about the same size as the out side DIA. of a stock valve seat .A 4mm intake will be hanging over the seat by 1 mm on each side.I know this cause i had my intake seats replaced.You might want to ask him if he is aware of that.
I will ask, Thanks.
 

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Discussion Starter #14
So what are you using for a throttle & cable setup ?
1. Throttle is ok, it pulls 42-43mm, enough for these carbs.

2. Cable thing is less sophisticated, at this stage it will be split cable pull only (like in Motoguzzi and Ducati have used). I will search for return cable solution too because of safety. I already have one but it does not fit with stock fuel tank.
 
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