elefant's 36 dellortos direct swap for weber?

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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ir_joep
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elefant's 36 dellortos direct swap for weber?

Post by ir_joep »

PLease can anyone tell me if my elefant's 36 dellortos (650 pantah) are a direct swap for the weber on my 750 sport.

If so, do I need to lose the fuel pump? What about the elefant? How will it run on the weber?

I want to swap because I need the weber on the elefant to fit under a modified P-D fuel tank.

Thanks,

Joep
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ducinthebay
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Re: elefant's 36 dellortos direct swap for weber?

Post by ducinthebay »

Yes, the 36 Dells should go directly onto your Sport, but you may need to do some jetting changes just to tune it better. With the Sport, you will need to keep the fuel pump. If you take out the fuel pump, then you run out of gas with a 1/2 tank still full. Make sure you put a T in the fuel line and feed the overflow back into the tank.

Cheers,
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
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ir_joep
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Re: elefant's 36 dellortos direct swap for weber?

Post by ir_joep »

Hi,

Many thanks,

Found out that the 36's were on the bimota DB1 (F1 engine). Some sites mention the F1 as well, but I also find 40 mm for the F1.

I have got the 36 dellorto's laying around (with cable and grip) so should be an easy swap.

Cheers Joep
dtm79

Re: elefant's 36 dellortos direct swap for weber?

Post by dtm79 »

Daft question of the week here ... What year/model(s) of dellorto carbs fit or should I say get used ... I have a couple of bevels and have over the years gathered dellorto's mostly from end 70's early 80's from memory 1 set of 36mm and a couple of sets of 40's ... Don't laugh to much please :? dale
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ir_joep
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Re: elefant's 36 dellortos direct swap for weber?

Post by ir_joep »

Hi

Mine are PHF's


Greetz Joep
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ducinthebay
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Re: elefant's 36 dellortos direct swap for weber?

Post by ducinthebay »

Put the 36's on a 750, and the 40's on a 900 motor.
While the F1 had 40's, it ran poorly on the street, and many owners swapped them to the 36's for street use.

Cheers,
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
btlofrum

Re: elefant's 36 dellortos direct swap for weber?

Post by btlofrum »

I looked at a Sport this weekend that had the Dell'orto conversion. (It's the one on Craigslist in Morristown, NJ, if anyone's interested.) My friend looked at the bike, but isn't interested.

At any rate, the carbs looked nice, and they fit easily with some cone-shaped filters on them. Bike sounded good--no sputtering or crackling. But it just idled on the driveway. We didn't take it for a ride--it's missing the gear selector (details!).

Looks like an easier conversion than the Monster/SS Mikunis on mine, that required a homemade airbox.
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ir_joep
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Re: elefant's 36 dellortos direct swap for weber?

Post by ir_joep »

Yes,

I swapped the weber for 36 dellorto's. I wanted to improve the drivability of the sport in town. On the weber it was awfull, however it did run very good above 4000 rpm.
The elefant's intake manifolds had a slightly smaller diameter than the sport's. I have to adjust that in the future.
For now it runs ok (no air filters), but it does need some jetting done to run better and filters.

The T piece (return) was already in the fuel system so I did not change that.

I will keep informed on the next steps. Next step will be stetting the dellortos up to F1 specs (to start with) 135 main jet horizontal cylinder and 140 vertical.

Cheers Joep
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ducinthebay
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Re: elefant's 36 dellortos direct swap for weber?

Post by ducinthebay »

Adding some rubber elbows to the ends of the carbs allows you to put some nice big air cleaners up above the carbs instead of cramming some small cone filters into the opposite head. 2" or 50mm works wonderfully especially if you have the short stock Dellorto velocity stacks (trumpets). Helps at idle and low speeds also.
Cheers,
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
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ir_joep
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Re: elefant's 36 dellortos direct swap for weber?

Post by ir_joep »

Yep, those elbows come with the elefant as well, including small trumpets

Sorted! (almost)

Joep
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ducinthebay
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Re: elefant's 36 dellortos direct swap for weber?

Post by ducinthebay »

Joep,
Can you post a picture of the Elephants elbows and air cleaner. I'm always trying to get a bigger air box on the Sport with the Dells. Since the Elephant came stock with it, I think it might be the best option, or at least worth copying.
Cheers,
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
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paso750
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Re: elefant's 36 dellortos direct swap for weber?

Post by paso750 »

Image
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ducinthebay
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Re: elefant's 36 dellortos direct swap for weber?

Post by ducinthebay »

Thanks for the picture. As I understand it, the air box is under the seat, so I guess I can't apply this to the Sport, but good to understand how it works.

Cheers,
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
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ir_joep
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Re: elefant's 36 dellortos direct swap for weber?

Post by ir_joep »

Hi,

From the top of my head the elbows have a diameter of 60 mm on the side where you want to mount a cone-filter.


Progress report on the webber dellorto swap

I have built the 36 dellorto to F1 standard specs. The sport was running pretty good. It starts very well, but had the same stumble between 2000-4000 rpm as with the webber, but I did not do any balancing or adjustments.

When I was riding as was thinking of which jets to use next and when I would do the balancing, when it started to rain.

The bike did not like this and was sometimes (most of the times) dropping 1 cilinder. I knew I had to sort this before even trying new jets. The 2000-4000 stumble might come from the ingnition?

Past weekend I converted to Webber back and started trouble shooting on the ignition circuit (Kokusan). With the ignition on I have only 8 volts on 1 coil and 9 volts on the other. Time for some serious checking.

High tension leads from the coil are not interchangable which is a pain.

I have been reading about a solenoid fix, but I'm not sure. I'll try and clean all contacts first.

For now Project Dellorto swap is on hold and if the 2000-4000 rpm stumble is due to the ingnition I might not even change after all cause the Duc sounds so much better with the webbers.

Anyway, thanks all you guys for helping me out.

Now I'm going to read about ignitions on the forum and the manual.

Thanks Joep
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Re: elefant's 36 dellortos direct swap for weber?

Post by higgy »

Most of what I have on my website also applies to the sport,only the jetting specifics are different,Relays,cam timing and jetting procedures will get you fixed up :thumbup:
http://mysite.verizon.net/vze2hw9t/
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There's no problem so bad that a little fixing can't make it worse! : )
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