Fabrizi bore questions

[Dio Dawg]

Aloha everyone. I'm also in the process of building a Dio motor with a Fabrizi 50mm bore i've just bought. My plan was to try it out with a mini stroke 44.1mm crank. I know its probably not as strong as the malossi mhr full counter crank. My concern is does anyone sell replacement rings? I've heard that these piston rings are pos and doesn't last. Also as baka mentioned the exhaust bore port exit measures 26mm compare to the 28-29mm on the polini corsa. Have anyone tried porting the Fabrizi exhaust port 1-2 mm bigger to match the exhaust (pg long, arrow pipe)? Anyone?

[Dio Dawg]

Dead thread =(

[LMH]

Haha dead thread. Earth to WM, you are requested to answer for your lack of dedication.

[LMH]

I wish I had answers for you dio dawg. Not many people have owned the fabrizi here, let alone ported it, or ran it on a stock or stroker crank. If this bore is set up for stock stroke and to produce top power at 11k rpms on stock stroke you may not want to mess with port timings too much. I assume there is a stroker version.
Im waiting on more to come in stock so I can do some port mapping. Some of these fabrizi ports are already so high on the cylinders (on the vespa fabrizis its 129 transfers & 192 exhaust) that you may actually harm the flow if you get that much closer to the head. Its always better to get a port map and calculations before just opening up things.
I would assume there has to be a few people here who have the maps and ported them though, and its nothing to fear.

[Red Eft Performance]

Aloha everyone. I'm also in the process of building a Dio motor with a Fabrizi 50mm bore i've just bought. My plan was to try it out with a mini stroke 44.1mm crank. I know its probably not as strong as the malossi mhr full counter crank. My concern is does anyone sell replacement rings? I've heard that these piston rings are pos and doesn't last. Also as baka mentioned the exhaust bore port exit measures 26mm compare to the 28-29mm on the polini corsa. Have anyone tried porting the Fabrizi exhaust port 1-2 mm bigger to match the exhaust (pg long, arrow pipe)? Anyone?

I didnt want to reply on this while it was in wheelmans build thread cause I didnt want to go off topic.

You can run it with a mini stroke crank but like the other bores be prepared to get the degree wheel out to check port timing and chances are like the Polini or Malossi the cylinder would require a little bit of machine work to get the squish Dialed in.
The mini stroke cranks are of lesser quality and arent as well balanced as the stock or Malossi cranks. Which leads to unneeded vibrations and reluctance to rev.
Just not worth the extra couple cc in my opinion.

I sell replacement pistons rings and gasket sets.

Just like any other engine build by all means match the exhaust port to the pipe. If the pipe is larger diameter than the bore outlet just be sure that that is the pipe you are always going to run cause you cant go back.

Keith

[Dio Dawg]

Thank you Keith for helping me clear some uncertainty in my mind. I'll definitely keep you in mind when I do need to replace the rings. I work at a scooter/moped shop here in Hawaii and we sell the correct thickness base gasket for the ministroke set up for the Polini/Malossi 72cc bore set up and I'm just guessing , if it fits on those bore it should fit with the fabrizi..i'll definitely will post update when I do install it. Unfortunately finding a full counter mini stroke crank is almost impossible now days. I was planning to use a mid size arrow copy chamber pipe on the Fabrizi set up but will use a smaller arrow pipe because it matches better on the Fabrizi bore. Want to port the Fabrizi exhaust port out but by the look of the butterfly port i definitely don't want to mess it up. Malossi/Polini ports are so much easier to work with.
I'll definitely will keep my mind on the malossi stock full counter crank on the installation.

[maddog]

I have an original 82cc fabrizi engine built 23 yrs ago with 1,000 mi. gets turned over every month, case ported, could be for sale for the right price

[veedubh20]

Dio dawg you must paid over price at full race import..

[Dio Dawg]

I didn't buy it from Full Race Import. I doubt they carry Fabrizi bores. Anyway I finally installed my Fabrizi bore onto a 44.1 ministroke stuffer crank. As I thought it would be the piston timing TDC and BDC lined up perfectly as to a stock crank like the malossi mhr. In my opinion as with a few others, the Fabrizi bore was made to fit a ministroke crank. They probably rework the piston and cylinder head to fit a stock length crank. But as wheelman showed some pics the timing was not perfect. Back to the installation...Using the stock base gasket the bore came with, I tried to use the Fabrizi cylinder head...with no luck since the cylinder head crown sits inside the cylinder and the piston top was hitting the head , I had to look for another Cylinder head to install since i didn't want to mess with base gaskets that will eventually change the timing in my port that was lined up perfectly. I got ahold of 50mm head. Upon installation I did a compression test and it was a mere 105psi... wasn't happy at all. I did a squish band check and had a lot of clearance on the top. So I next milled my head down as much as I could and got a compression range of 135psi. I acceptable range that I can work with but still wasn't satisfied. Will be looking for another 48-49mm head and milling it also to try to achieve a 140-150 psi compression but in the mean time I did install that head and started it up . Im running a 28mm OKO jetting at 55 pilot and 148 main, 7.5g weights all around , Malossi Fly clutch with blue race springs , not sure the exact rpm but I believe they're around 4000rpm and a 20% center spring, 7.3:1 gear, V8 stroker pipe. More tuning is needed as I will install a mid size arrow copy pipe and increase my jetting. Ran it around the block a few times. My reaction and thoughts...definately a lot of torque and power on the low end and good power mid range. At WOT i noticed the power wasn't great asa well tuned 72cc polini corsa mini stroked set up but as i mentioned more tuning is needed but there's potential in this bore. More to come.

[Red Eft Performance]

So what were your port timings with the Mini stroke crank and stock base gasket?

[Dio Dawg]

Sorry I didn't post any pics...probably worth more than words to show the piston in reference to TDC and BDC. If I do switch heads to try to get a higher compression I will sure to take pics of the set up. But till then in reference to timing at TDC the piston top not the dome sits .5-1 mm just a rough estimate below the cylinder head and at BDC the piston sits 1mm below the exhaust port. I've just got back a 49mm cylinder head milled down hopefully to try it out at a later date and hopefully it'll help me increase another 10-15psi in compression.

[Wheelman-111]

Greetings:

Piston position matched port location perfectly on my stock-stroke Malossi crank. I posted the wrong pic one time, sorry for the confusion, but I believe the Fab Fifty is designed for 41.4mm stroke. My squish with stock gasket was perfect. No head contact, and flush with the bottom exhaust port at BDC. AND IT RUNS OVER 70.

Better run 100 Low-Lead if you increase compression at all; mine measured 145.

[Dio Dawg]

Wrong pic that's glad to know but it did sure look like a Fabrizi bore at BDC that didn't clear the exhaust port. That's great that the timing is perfect for the 41.4mm stroke crank. Will be installing one for a customer that requested a malossi mhr crank.

[Dio Dawg]

Swap my stroker V8 exhaust with a mid-size Arrow copy pipe . What a difference it made, the power just opens up at WOT. I have my motor mounted on my 1987 Honda elite and it wants to do wheelies even with my 7.3 to 1 gears. I'm amazed and happy with the Fabrizi as I had some doubts about this bore.

[LMH]

So whats the scoop on your port timing? We still havent seen or heard anything about it since this thread went dead. Just hope you did do a port map before and after for your own sake later down the road if you want to replicate it. By eye just doesnt cut it 99% of the time.