Fab Flash 7: Fabrizi 50mm Cylinder Kit (74.6MPH)

[Wheelman-111]

Greetings:

Minor scare on a downwind check-ride. Moments after going WOT, the engine sputtered badly and lost power. Four-stroking, more like six-stroking and couldn't get it faster than 35MPH. On a 75-MPH limit highway - not so good. Temperatures dropped to 275, so I pulled into the breakdown lane and kept nursing it heading for homea, only a mile ahead. Turned a corner and it lost ignition altogether.

Thanks to the funky riveted-on cover's flexibility, I managed to pry it open by the roadside. Found the culprit; the spark plug wire. It was lying NEXT TO the sparkplug - not loose but entirely off the plug. It's amazing it ran at all. I suspect my CHT wire was too tight. Over bumps it exerted a little prying action on the rubber plug cover, and eventually worked it all the way off. Re-installed, it fired up fine, but missed a nice top speed Opportunity downwind.

Today jetted down from 155 to 152. It ran well, but picks up speed when slacking the throttle from Full to 7/8ths - a sure sign of too small main. I installed the 158 for testing manana.

[deuce217]

Those are some big ole jets you're playing with. I bet MPG is awesome! Glad to hear it was only a wire issue.

[Wheelman-111]

Greetings:

Surprisingly the mileage isn't a whole lot worse than the Malossi, probably better than the Corsa. That's because like the Malossi the Fab makes pretty good power without having to rev to the moon. Thanks to my shiny new Vapor, I can tell you that 40-45MPH - which is the majority of errand-running riding I do - requires only 8000 RPM and the throttle just cracked open about a fourth. WOT probably would suck a lot more costly AvGas Premix, but around town that's seldom necessary. The JJF needle I'm trying blocks the thirsty Main pretty completely at part throttle. Oh, and temps even with the 155 Main didn't exceed 375. It's already getting warm down her in Donmesswit, so when it gets d*** hot I'll probably have to rethink the jetting again.

[Dio Dawg]

It ran well, but picks up speed when slacking the throttle from Full to 7/8ths - a sure sign of too small main. Umm I don't think so...its a sign of a too BIG main.

[bonesv]

It ran well, but picks up speed when slacking the throttle from Full to 7/8ths - a sure sign of too small main. Umm I don't think so...its a sign of a too BIG main.

+1 too large

[ped]

Hi wheelman.
A lot of factors go in the tuning. fuel, humidity, jets. put a smaller main jet until you get a better response @WOT.
sooner or later you going to hit a sweet spot at any throttle position.
It's going to put a smile on your face.
Nice work on the fabrizi setup.
More MM more power.

[Wheelman-111]

Greetings:

I disagree, Dawg. Here's why. With the throttle open wide and all 28mm of throat diameter pulling high-velocity air over the venture, a too-small main delivers insufficient fuel for best combustion. Closing the air inlet by 1/8 does little to diminish fuel flow out the jet, but the carb now delivers only say - 24mm of effective throat diameter. Now the mixture has enough fuel to burn well, and the power picks up appreciably. I've been doing this for a long time - not Honda scooters, but snowmobiles, vintage Japanese Multis, and Harley Sportsters. For the record, the 158 ran very well for the short test ride. Can't prove more because Tornado Warning here in Donmesswit this afternoon.

[Dio Dawg]

3 guys on the board says it too big.

[Wheelman-111]

Greetings:

Will do more testing next weekend and report.

[ped]

Greetings:

I disagree, Dawg. Here's why. With the throttle open wide and all 28mm of throat diameter pulling high-velocity air over the venture, a too-small main delivers insufficient fuel for best combustion. Closing the air inlet by 1/8 does little to diminish fuel flow out the jet, but the carb now delivers only say - 24mm of effective throat diameter. Now the mixture has enough fuel to burn well, and the power picks up appreciably. I've been doing this for a long time - not Honda scooters, but snowmobiles, vintage Japanese Multis, and Harley Sportsters. For the record, the 158 ran very well for the short test ride. Can't prove more because Tornado Warning here in Donmesswit this afternoon.

You are right wheelman.
I meant to say a little more tuning you'll find the best combination that works.
and you will be very happy.

Are you allowed to ride on the freeway?

[LMH]

It's all in the sound of the exhaust note at wot.

[Wheelman-111]

Greetings:

Grizzled, hairy Wheel-ears are not sensitive enough to discern rich/lean by sound alone, particularly with 70-MPH wind roar masking the note. I go by CT reading, palpable thrust and occasionally plug color. (Does anyone else find it a giant PITA to thread a spark plug tangled in a CT sensor?

Allowed schmallowed. If my scooter can keep up with traffic, the Gendarmes have no beef. Texas school zones have 75-MPH speed limits. Several routes here allow 85, and people routinely cruise at 90. OK not many 50s do that, but nobody's going to ticket me for riding a 49RR on the highway. Unless I exceed that 75 MPH limit that is.

[ped]

Hi WM.
Very interesting, no beef.
If I were to get caught on the highway the scooter would be impound and I be in jail.
All my speed tests are done on a few routes.
People routinely cruise at 90? I would be looking at one year license suspension.
Speed limited 65 tops. and look out for deer and moose .

[Wheelman-111]

Greetings:

I'm sorry things have gotten that way in "northeast usa". What state?

In some ways, Texas really is a different country. I had business in Florida a few months back. I understand that the roads there are more crowded, but it struck me that the speed limits were absurdly low almost everywhere I drove. There was no shortage of Constabulary to enforce those limits, either. All civilized places have Nanny forces to tell you what to do. Nowhere I've seen has less of that Nannyism than Texas, and I like it.

On those few occasions where bright-red Flash, festooned with obviously Aftermarket paraphernalia, has attracted the attention of Police, the interaction has been of curiosity and admiration rather than concern for Illegal Modification. I like that, too. Had it safety inspected last Friday. Yes, we do have some rules here... The coiled Chamber pipe and oversized carb drew comments, but basically they just want to know the tires aren't bald and the blinkers work. $14.50 and I'm good for another year.

In Quebec, they tried to deny my brother's vintage Sunbeam Tiger certification because it lacked Sun Visors! Seriously?! He actually had to find and pull out a brochure from that year showing that they were optional, and thus the car was legal in the year it was built. They grudgingly passed it, but with that "Don't let it happen again." attitude so common in Bureaucratic Bullies. I don't think I could live in Canada any more.

[deuce217]

That sounds crazy. Washington is pretty good as far as that stuff goes, at least in Eastern WA. I drive my elite 50 on there to do my tuning runs, I have never had an issue. Never been harassed by an officer at all. Once one told me to "cool it" when I was doing wheelies on the road when I thought nobody was around.

Texas,

I love the place and someday might journey down there for good. I have been there several times to Ft Bliss, and Goodfellow AFB. The people are friendly (especially the ladies) and thats where I learned how to cook a beef brisket on a BBQ. The occasional dry county will throw a few soldiers for a loop when they are trying to get a 6 pack, but you just need to plan around that and everything is fine.