Maintenance & Technical > KX500 Aluminum Frame Conversion (AFC)
HELP w assembly
Motorrad:
--- Quote from: GREENKAW24 on January 05, 2012, 12:10:10 PM ---
--- Quote from: Motorrad on January 05, 2012, 03:09:57 AM ---How can they tell you all that and not tell you the head CC?
I have been bit by head CC before...
wanted 40CC.. ran bike, was down on power from where I thoguht it should be.. ended up being at 46cc..
Yea.. thats only like.. A TON OF COMPRESSION POINTS differance...
when you get up in the Big bore motors.. it really matters..
40cc to 42cc is the differance between 15:1 and 13:1 (once again going off my bad memory here)
--- End quote ---
40cc would be 13.5 to 1, and 42cc would be 12.9 to 1. (Stock KX500) Compression ratios don't change as drastic for every cc when you get to the big motors.
2cc difference on a 125 can change 2 whole points.
--- End quote ---
I ment CC changes alot when you go from 86mm bore to 90mm bore... changes comp ratio... alot...
81cr450:
Piston Dome cc's guys sorry for any confusion. I asked for piston dome cc so I could use the calculator Motorrad posted & just figure it myself. It was the only spec I was short. Where the piston isnt a true flattop.
47cc head chamber is what I ended up with, for 550cc's of motor.
4-5 degree squish angle. .039 squish including the gasket
.000 deck using the .020 factory base gasket.
So Todd's initial quote is good
12.5:1 & 7.5:1 93-100 octane
The pump here only spits out 91 octane, not 93. I believe due to elevation. With 93-100, 93 is bottom of the spec & the 91 at the pump is probably not gonna cut it.
81cr450:
Here are couple pics of assembly. I have a set of old school head porting stands that work pretty good to hold the case while its loaded. A pic of why I dont like the plastic case bearing on the clutch mainshaft & a pic of the pinned type that should be used. Also a shot on using a half sealed bearing on the sprocket side of the case to help keep the poo out, & oil in.
81cr450:
The rings your piston comes with is kinda what your stuck with but this type is the best as it captures the alignment pins so the cant come out
Also had to recess the powervalve access plate screws to clear the frame. The screws that hold the rear brake guide on the K5 worked perfect
81cr450:
Mommy :-o
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