Steven
12-27-2002, 05:48 PM
I'm rebuilding my 440EX and I need some advise.
On a side note, kudos, to Ross Pistons! They stock 89.1mm, 89.3mm, and 89.5mm 11.2:1 (withXR400 gaskets) pistons for our EX's for a mere $125.
I will be taking my cylinder to the machine shop for them diagnose the damage on the sleeve so they may recomend how much overbore I need in the piston size. I don't want to purchase a piston then have it not be large enough to replace the scorched metal in the sleeve. Is this the proper way to make the preliminary decision of what oversize piston to use?
This question relates to compression ratio. I have already purchased the gasket set from Cometic. I got the .025 head gasket and the .010 base gasket. This combination will put me closer to a 12:1 compression ratio with the Ross piston. My first concern is octane rating. Will 100 octane Cam2 race gas be sufficient for that amount of compression? I can buy it here for under $4/gallon. Another concern of mine is heat. I fear the 12:1 is going to cook the oil and ruin my new top end. I can't afford and aftermarket oil tank yet. What are your thoughts on this?
I am purchasing new rockers and cam... together this time. I know from my experience with cars that the metalurgy between the cam lobe and rocker arm is important for longevity. The Hotcams Stage II seems to make sense because they apparently match cam metal hardness to that of Honda's OEM rockers by avoiding weldups/regrinds and I understand that they are fresh cores cut to spec. Hotcams are an inexpensive cam in relation to others. Why? Are they a good/reliable cam for sport riding? I don't race.
Last question is on the cylinder head. I am sending the head out for a 3 angle valve job (on serdi machine) and port clean up. As I understand it, the intake valves are junk. Mine are three years old now so'm I'm replaceing them with the OEM ones for the fresh cut. I noticed the exhaust valves are twice as costly, likely due to the better metal thay are made from. Should these be replaced as well or can I just have them re-cut?
I really need some expert advise here. The guys at my local Honda shop are clueless on this stuff.
Thanks!
Steve
On a side note, kudos, to Ross Pistons! They stock 89.1mm, 89.3mm, and 89.5mm 11.2:1 (withXR400 gaskets) pistons for our EX's for a mere $125.
I will be taking my cylinder to the machine shop for them diagnose the damage on the sleeve so they may recomend how much overbore I need in the piston size. I don't want to purchase a piston then have it not be large enough to replace the scorched metal in the sleeve. Is this the proper way to make the preliminary decision of what oversize piston to use?
This question relates to compression ratio. I have already purchased the gasket set from Cometic. I got the .025 head gasket and the .010 base gasket. This combination will put me closer to a 12:1 compression ratio with the Ross piston. My first concern is octane rating. Will 100 octane Cam2 race gas be sufficient for that amount of compression? I can buy it here for under $4/gallon. Another concern of mine is heat. I fear the 12:1 is going to cook the oil and ruin my new top end. I can't afford and aftermarket oil tank yet. What are your thoughts on this?
I am purchasing new rockers and cam... together this time. I know from my experience with cars that the metalurgy between the cam lobe and rocker arm is important for longevity. The Hotcams Stage II seems to make sense because they apparently match cam metal hardness to that of Honda's OEM rockers by avoiding weldups/regrinds and I understand that they are fresh cores cut to spec. Hotcams are an inexpensive cam in relation to others. Why? Are they a good/reliable cam for sport riding? I don't race.
Last question is on the cylinder head. I am sending the head out for a 3 angle valve job (on serdi machine) and port clean up. As I understand it, the intake valves are junk. Mine are three years old now so'm I'm replaceing them with the OEM ones for the fresh cut. I noticed the exhaust valves are twice as costly, likely due to the better metal thay are made from. Should these be replaced as well or can I just have them re-cut?
I really need some expert advise here. The guys at my local Honda shop are clueless on this stuff.
Thanks!
Steve