Fabrizi 50mm Squish

[DirtyE]

Im going to have to run my timings again tomorrow. I took .2mm off the top of the barrel tonight and am sitting with an average of .7mm squish. The fabrizi "manual" which is a 1 page sheet suggests squish of ,6-,7mm.

Taking that .2mm is going to change my timings once again by a degree or two because im less distance to the deck. I can run the numbers at home cause I've got a * windows 8 box without excel.

Yes road race(to me) is sort of like drag race from stop light to stop light. Ill be riding with Whitey and his 129cc beast so I've got to squeeze a lot out of this kit. If I push it too far, I buy another kit. $275 for anew isn't bad. I dont really have $275 to blow per say, but im not blowing a $400 evo/mhr kit either.

To be honest, this stuff is fun. Working with metal, tiny measurements, calculations. Then with the case porting you get to be creative and expressive.

Here is a link to another thread regarding my build. Blowdown should still be around 30 which shouldn't be too pipey, but the ports will be higher. There is a pic of the head from the fabrizi kit in this thread as well: viewtopic.php?f=4&t=30566

Edit: I just saw your post of 187/128/30. Were gonna be in the same ballpark there. What pipe are you running? My main concern was finding a descent pipe. I got lucky getting a c16 from G9.

[Wheelman-111]

Greetings:

I don't think shaving the barrel is really going to change your timings which is determined by the piston stroke/crankshaft, which didn't change. The piston isn't going any higher, you just brought the ceiling down. Your compression will increase a bit however.

[DirtyE]

The distance from the top of the port to the top of the barrel has changed. But you know, you might be right because of where the piston sits at BDC. A thinner base gasket wouldve brought the floor of the ports below the piston crown, so it wasn't an option. I wanted to keep the crown and the port floors even. So I guess they will still be open the same amount of time, just with less room above. Ah, its been a long day. You're right Wheelman. My bad.

[1man8scoots]

Blow down is perfect at 30 for a well ported and flowing case, a bit much if you are going mild. Necessary for top end power but the big winner is the size of the boost port on these fabrizi. I'm going to do a triple exhaust port on a 55mm cylinder next.
Wheels is right, no change in timing just compression.
I have a few pipes to use, I don't like the fabrizi I have on it just based on the sound. I will probably stick with my motorio c16 in the end but I'll play around with a few.

[DirtyE]

Fabrizi is a funny company. Cutting edge, well known, but they leave work for the end user. With cylinders its ok, with pipes not so much.

[DirtyE]

Here's my dilemma. One of the factors of equating timing is port ceiling to top of deck measurement. Removing meat from the top of the barrel shortens the distance, raises port timing as per my spreadsheet.

Here is a different scenario though. If I would have been able to take that meat off the head timing in my calculator spreadsheet would have not changed.

Im consulting with bram right now on google hangouts to get his word whether this is a calculator error, or I am missing something.

[1man8scoots]

When milling the deck and not using more base gaskets the timing stays. Unless your changing the length of your crank. TDC is TDC. Whether it be TDC at the deck or TDC in the head it's the same. Compression and squish is what's changed and depending on how far you go Msv can also. If you change the head deck height the compression and, depending on head design, Msv will change. Changing the head design will change Msv more than closing your squish tho. Fun stuff!

[kauaianman]

i think the calculator assumes you are raising the top of the exhaust port and not cutting down the top of the cylinder.

[DirtyE]

Yes, it just uses the measurement from top of port to deck. It took a minute or 10 for me to figure that out with the help of others here.

[Trafficjamz]

does the head on your fabrizi kit stick down into the cylinder?

[whitey]

I don't think so

[DirtyE]

Nope.

[Trafficjamz]

Here is mine.







I wonder if the cylinder is the same.

I know that it came with a different piston in the original kits offered by RedEFT

[DirtyE]

http://www.hondaspree.net/phpBB3/viewto ... 6&start=15
thats a different head for sure.
Page 2 has a pic of my head.

[1man8scoots]

The single ring kit has a different cylinder and head then the old 2 ring style. Mine is the protruding style as well. That new design looks like it could use some clean up. Might be able to use the head with a stroker set up with the double ring.