Andrew1234
Active Member
*dyno
Phantom 85 or minarelli
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GW's Motorized
Well-Known Member
Yeah, probably. My bike will top out at 40 with 4hp.
The phantom is based on a Saw that made 7hp from similar displacement. It's not a direct copy, and the intake side in particular was restricted some to likely tone the power down, but giving it very good intake "draw" through the OZ reed and Bofeng carb. Realistically, it likely makes around 5hp - ish. The exhaust port is huge relative to displacement much like the BT80, which between that and the great transfer port design is where the Phantom makes most of it's power.
Open up the intake side and put on a larger carburetor and it really wakes up, likely putting it at power levels similar to the saw it was based off of. Put a REAL expansion chamber on it, one designed for the size of the engine, like a 80-85cc dirt bike pipe, and you have to upgrade the clutch.
Open up the intake side and put on a larger carburetor and it really wakes up, likely putting it at power levels similar to the saw it was based off of. Put a REAL expansion chamber on it, one designed for the size of the engine, like a 80-85cc dirt bike pipe, and you have to upgrade the clutch.
GW's Motorized
Well-Known Member
@DAMIEN1307 told me the phantom has a smaller exhaust port than my BT80 which I found surprising
When and where?...I don't remember saying if it was smaller or not...lol...The P-85 exhaust port is 60 mm stud to stud with a 28 or 29mm oriface outlet...Is that smaller or bigger than the BT-80 since I have not ever seen one in person.
Andrew1234
Active Member
Would a mz65 be good foot as well?
Andrew1234
Active Member
For
Remember that the BT80 exhaust system uses a socket style interface similar to a motorcycle, so the opening is larger in diameter in appearence than its functional diameter. The I.D. of the header pipe would be a more accurate way to compare them. I do know that the Socket diameter or the port is 35mm, but looking at the thickness of the sleeve for the socket leaves me to estimate the ID of the exhaust is around 25mm. Close to the same as the Phantom, but it would be a little smaller. More importantly, the BT80 muffler uses a standard body muffler like every other 2 stroke exhaust, which gives a big edge to the Phantom in terms of stock exhaust flow, which has a better muffler design.
It's not the most ideal for the size of the Phantom. There has been a couple of people that have adapted an MZ65 to a Phantom and were quite happy with the result. It just leaves a lot on the table in terms of efficiency but it is still going to make more power than the stock system. I have also seen a build use a jog pipe, and it also performed well and opened the power up. All of these Phantoms had to upgrade the clutch. The stock clutches don't have enough clamping force to handle an uncorked Phantom, which is one heck of a torquey little engine
GW's Motorized
Well-Known Member
Any suggestions for upgrades?
I'll probably get that one then. Just be aware that both styles can potentially hit your leg/foot easily, depending on the bike and/or seat positioning. The cdh67 is more prone to it because the chamber is bigger. I am a big fan of the real mz65 pipes. They cost quite a bit more though.
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