Dels v Mikuni

  • Thread starter Thread starter Davo
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Laverda SF said:
Really no difference between a Dellorto and Mikuni except a Mikuni is 1/2 the price.
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The main difference when I put Mikuni RS36 carbs on my Jota was the much improved fuel consumption.
Did a dyno run before and after. Power curve with the Mikunis was pretty much identical to what we got with the Dellortos, but the air/fuel mixture trace was a lot better controlled.

Maybe my Dellortos were past their best, but the Mikunis I used were second-hand too, so the old vs new effect was probably not the main difference between them.
 
Dellortoman said:
Maybe my Dellortos were past their best.
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Valid point, comparing new for old is never a control experiment unless you have the dyno figures to hand.  But just re starting alone, worth the change.
Seat of the pants tells me low end third gear response is way better, but that might mean (for example) that the pumpers in the dels were past their best.

Way less than emprical, that seat of the pants opinion.....
 
I fitted brand new Mikunis on my tuned 180 1000.
Best I have seen was around 48 (UK) mpg.
Never got that on any 180, but did get that on my Corsa with Dellortos.
I know, apples and oranges.
At least the 180 (POP) is in the same state of tune as the Corsa.
Corsa spec head, high comps.
Wonder what anyone else got with Mikunis on a 120.
 
Apparently a lot of you Breganzie enthusiast in this forum have never used an open mouth Delertto 30A square slide without an accelerator pump. Probably before your time - Capable of revving a 70 SFO to 8 Grand with proper jetting and exhaust ;o)

I've run Dual 38 open mouth Mikuni's with accelerator pumps on a 440 2 stroke Kawasaki engine in a John Deer Sport Fire snow sled and Cafe 500 Suzuki Titans.

Neither application used Air Filters.
 
Grant said:
I fitted brand new Mikunis on my tuned 180 1000.
Best I have seen was around 48 (UK) mpg.
Never got that on any 180, but did get that on my Corsa with Dellortos.
I know, apples and oranges.
At least the 180 (POP) is in the same state of tune as the Corsa.
Corsa spec head, high comps.
Wonder what anyone else got with Mikunis on a 120.
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I would have no doubt the Mikunis can deliver better MPG than the Dellortos. AIRC the range of Mik jets and needles have a finer resolution.

About the best I have seen on my tuned 3C with Dells is 45 MPG British or 37 MPG USA.  Most rides get me about 33/30 MPG USA average if I really flog the bike in the North Georgia foot-hills.
 
Fuck Gas Millage or fuel mixture _ You have to win the race whether it's 1/2 a mile to 800 miles.

Then the Amil Carb - What can I say about the Amil? 1st of all Bikes using Amils didn't have electric starters until the 70 Breganzie SF and SFC - They were all kick starters (BSA, Triumph and Norton's) and you were lucky to fire up your ride after 30 kicks before breaking your knee and thrown over the bike to get them started. Amils where a great performance carb providing you could start the bike.

The original 70 750 SFC came with Amils
 
sorry guys, if you worry bout fuel or smooth performance, a laverda may be not yours!
on my road bike i like it authentic, bit rough, a laverda sounds only after a laverda with dellortos, and this brutal accleration, and look (made in italy-stamp)! give a shit for this little ride about fuel-hello
anyway, i allways findet it strange when ducati stardet using showa.....
 
I did not go for FCR's because auf Fuel economy but because of throttle response, accurateness of adjustment and overall technical advantages over the Dell'Ortos.

I rode a perfectly adjusted, original 1000 SFC after I had mine tuned. I would never consider to go back...
 
Laverdalothar said:
I did not go for FCR's because of Fuel economy but because of throttle response, accurateness of adjustment and overall technical advantages over the Dell'Ortos.

I rode a perfectly adjusted, original 1000 SFC after I had mine tuned. I would never consider to go back...
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Thanks you, Lothar! Any suggestion that a bike will run smoother, produce more power, use less fuel with Dells than FCRs is not based in fact. Don't worry, there's little chance your Lav is going to go from a wild, untamed, rough beast to a silky, civilised, sophisticated modern moto by fitting modern design carburettors is also a bit of a stretch. They just make the engine feel incredibly responsive.

As for  Ducatis using Showa, Yamaha use Brembo, Laverda use Nippon Denso - so???
 
Laverdalothar said:
I did not go for FCR's because auf Fuel economy but because of throttle response, accurateness of adjustment and overall technical advantages over the Dell'Ortos.

I rode a perfectly adjusted, original 1000 SFC after I had mine tuned. I would never consider to go back...
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FCR 41 comp to Min 36 of course day and night...  :o
 
bazzee said:
I believe FCR39s are Keihins not Mikunis...

cheers

bazzee
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Yes, its a bit off topic? Keihin FCR are actually "Racing only", the Mikuni RS36 are actually for Jap stock bikes. Anyway its hard to compare a 32 Dellorto Round Carb with much bigger japanese Flats.... it would be more interessting to compare them with big Dellorto Flats
 
hochkoenig said:
Yes, its a bit off topic? Keihin FCR are actually "Racing only", the Mikuni RS36 are actually for Jap stock bikes. Anyway its hard to compare a 32 Dellorto Round Carb with much bigger japanese Flats.... it would be more interessting to compare them with big Dellorto Flats
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That is not true, sorry. FCR's have been used on several Jap street bikes (Mostly the "R" or "RR" versions). You can notice that in these cases, they have been used with choke and partly even with throttle position switches or sensors (to change ignition curves f.e.). Mostl, if they were used on a road legal bike, they came in straight diameter numbers (like 40mm instead of 39 or 41mm).

Yes, the original discussion is about Miks against Dels. However, the FCR's and the RS are very similar carbs (smooth bore, flat slides etc.) with almost the same advantages against the Dell'Ortos. Therefore I do not see any major difference in using FCR or Mikuni RS, but both beat the Dell'Ortos on the same points. My experiances are mostly FCR driven, that's why I refer to them in this discussion. I have a set of (unused) RS though laying here, which will go onto the Motoplast project.
 
Orright, I'm going to weigh in here with something I've been making inquiries about (too much time on my hands). Mikuni TMRs, been here discussed here a few times as an alternative to RSs. Tophams in Germany offers either Mikuni as a preconfigured bolt-on set for what's probably a fair price, but just be sure you're sitting down when you actually read the price. In the US, Mikuni dealers don't sell TMRs, and I even got my local Sudco guy to inquire from Mikuni USA about a special order. No, and hell no.
OK, but in Japan, Yoshimura has modified TMRs with a jet needle that's been turned into a multi-orifice spray bar. They claim huge increases of flexibility and rideability, power increases, improved fuel consumption, easier starting, easy tuning, makes you more attractive to supermodels (I may have mistranslated that a bit but it could have been what they were saying...).
So, I asked Topham's if they could set up three user-supplied (by me) TMR-MJN36 (MJN = Multi Jet Needle) carbies for a Jota. No, they're a Mikuni dealer, I'd have to go to a Yoshimura dealer. And they can't sell me a parts kit, there's some machining involved.
Next step, email Yoshimura, will they let me send a set of basic TMRs hacked by Tophams to them for conversion to MJN spec? They do advertise that they do the MJN conversion. And if so, how much?
And that's where it stands. If they ever respond I'll share what they say. There's no way I can afford any of this but asking doesn't cost anything, and somebody else might be interested.

Ken
 
Cool! All new to me. I've got a couple of pairs of FCR 39s that came from a Japanese four. Can't afford them new and I'll be more than happy with them.

But I would like to know more about this MJN stuff - never heard of it. I suppose it's even closer to fuel injection than FCRs? Now I wonder what a Keihin EFI system off a new Royal Enfield 270 deg twin would set me back ...? Hmm ....
 
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