15:15 vs. 16:16, Let's talk about that.

Let's talk about the Dellorto15mm and the 16mm SHA. Do you have a preference? Does it matter? I mean... 1 millimeter diffrence!? But alas, they exist so there has to be pros and cons.

So lets talk about it.

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Re: 15:15 vs. 16:16, Let's talk about that.

Brandon Weiss (Detective brandon to you) /

i hear the 16 is more finicky somehow.....at least the new ones.

Re: 15:15 vs. 16:16, Let's talk about that.

154mm^2 vs 177mm^2 inlet area

I personally havent been able to tell the difference between the two, but each one was on a different bike.

Re: 15:15 vs. 16:16, Let's talk about that.

honestly I always went with 15's.

why? intakes.

Almost all the intakes are sized to 15 anyway. As a result I've got no real experience with the 16's except having run a 16 on a 15 intake, which unsurprisingly was not as good as a 15 on a 15 intake...

Re: 15:15 vs. 16:16, Let's talk about that.

probably where the "finicky" reports come from too.

"just running undersized intakes and it's not behaving as i'd like so i'll call it finicky."

Re: 15:15 vs. 16:16, Let's talk about that.

Captain Janeway /

This is where we need CW or a couple of other guys to chime in with theory.

Re: 15:15 vs. 16:16, Let's talk about that.

Probably Fred /

I like the 15mm sha way better than 16mm especially on piston port kits for the bigger the bore size is in a carburetor the smaller diameter atomizer needs to be for a finer spray mist to fill the whole bore in the carburetor and a sha doesn’t have normal replaceable atomizer and needles like a normal carburetor does.

For easier starting and easier jetting for me the 15mm gets the nod but on some French bikes the 16 mm sha seems to work OK,

I like the the 14mm bing over a larger15mm bing on pp kits (due to easier to start and and jet) too though on reed kits the 15mm bing rules

Re: 15:15 vs. 16:16, Let's talk about that.

>>>taykoff [s2m] /

I've not tried either...I always just bore out my 14.12's to 15.15's using Graham's tutorial, so I haven't needed to buy one.

Re: 15:15 vs. 16:16, Let's talk about that.

Woolfardisworthy bullfardisworthy /

I had a theory about the lack of slide cut angle on the stock 16.16s causing havoc at mid throttle and creating a lean condition, i never investigated but it could be a cause of problematic tuning.

edit: it may relate to mismatched intakes as well, again causing havoc on mixture flow. (edited)

Re: 15:15 vs. 16:16, Let's talk about that.

i have a 15mm on a stock moby(15mm intake), and a stock pug (15mm intake) and a 16mm on another pug...they are all about the same but the 16mm on the one pug has amazing throttle response...of course it also has a 15mm intake, 70cc kit, mbk cdi, performance pipe, tuned vario...so there's that...

probably about the same

Re: 15:15 vs. 16:16, Let's talk about that.

> Woolfardisworthy bullfardisworthy Wrote:

> -------------------------------------------------------

> I had a theory about the lack of slide cut angle on the stock 16.16s

> causing havoc at mid throttle and creating a lean condition, i never

> investigated but it could be a cause of problematic tuning.

>

> edit: it may relate to mismatched intakes as well, again causing havoc

> on mixture flow.

I ALWAYS have to tune the slide on SHAs. Lots of good info out there on this.

Re: 15:15 vs. 16:16, Let's talk about that.

I've had pretty good luck 16.16, I personally hate SHA's but I bought a bunch when they were on sale and put them on a variety of bikes with no issue.

A carb is a carb is a carb, they all need tuning and some are easier to tune then others but they can all be tuned.

Re: 15:15 vs. 16:16, Let's talk about that.

time is money, as sizes go up, it's harder and harder to tune across the entire throttle range with limited tuning options.

add a needle, or idle jet, boom, options open up.

comparative expense maybe.

Re: 15:15 vs. 16:16, Let's talk about that.

!5/15 Dellorto has always worked perfectly on my StreetMate,a 64cc kitted bike.Idles great and starts always. Gets 100 mpgs so I have no complaints in the last 15,000 miles or so. don-ohio (:^)

Re: 15:15 vs. 16:16, Let's talk about that.

Jimmy Cincinnati /

I ran a 16/16 on my old tomos blue bullet with great results. Of course i custom made a shorty intake for it that was flowing a true 16mm.

People that put 15/15's on Tomos puzzle me. Most buy a bigger carb and put it on a stock intake. Even the aftermarket "L" intake that claims to be 15mm only flows at 13.5mm.

Re: 15:15 vs. 16:16, Let's talk about that.

***VANILLA BLUNDER*** /

13/13 forever. :)

Re: 15:15 vs. 16:16, Let's talk about that.

> Jimmy Cincinnati Wrote:

> -------------------------------------------------------

> I ran a 16/16 on my old tomos blue bullet with great results. Of course

> i custom made a shorty intake for it that was flowing a true 16mm.

>

> People that put 15/15's on Tomos puzzle me. Most buy a bigger carb and

> put it on a stock intake. Even the aftermarket "L" intake that claims to

> be 15mm only flows at 13.5mm.

Good point,Jimmy! The intake should be matched up. I've had to grind out a few of them. When a 15mm opening suddenly closes to 13 or so, smooth flow suffers.

Doesn't hurt anything, but crimps the effect the larger intake would've had.

don-ohio (:^)

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