draggins10 Posted March 11, 2015 Report Posted March 11, 2015 I'm asking here because this site is much more active than the yfz site and I also own a banshee. Anyway, I picked up a yfz450 non running as a project. I cleaned the carb and gas tank/lines and it started right up. I got it to idle fine but once I hit the throttle it backfires bad. It has bill ballance pipe, k&n filter and it has been ported. Right now it has a 165 keihin main jet. Can someone suggest where I should go from here? Thanks Quote
draggins10 Posted March 11, 2015 Author Report Posted March 11, 2015 Here's a pic of the port job btw, I don't know if its a backyard hack job or not Quote
Burke Posted March 11, 2015 Report Posted March 11, 2015 42 pilot?... what needle and clip position? 165 should be damn close?... hows the AP diaphrag, squirt strength, and duration? Quote
draggins10 Posted March 11, 2015 Author Report Posted March 11, 2015 42 pilot?... what needle and clip position? 165 should be damn close?... hows the AP diaphrag, squirt strength, and duration? I'm pretty sure it has a 50 pilot, and I'm not sure about the needle position. I have to take the carb off and check again Quote
draggins10 Posted March 11, 2015 Author Report Posted March 11, 2015 Its an 06. I know its missing a bolt, I put another one on already. But is there supposed to be some sort of gasket on there? Quote
draggins10 Posted March 11, 2015 Author Report Posted March 11, 2015 It won't let me upload a close up pic for some reason, but is there supposed to be a gasket between head pipe and head? Quote
sleeper06 Posted March 11, 2015 Report Posted March 11, 2015 175 main, 48, pilot ncvq needle 4 th clip , air screw 3 turns out, I doubt it's the jetting,if u sprayed the the carb slide with cleaner the oring expands and fucks throttle opening, my suggestion would be #1 leKdown test to make sure valves are sealing at tdc #2 check valve lash I'll bet dollars to donuts that where the problems lie , need to re shim valves before you damage something #3 make sure your excellerator pump is skirting fuel good #4 all else fails drop it off lol I've built some killer 450s Quote
sleeper06 Posted March 11, 2015 Report Posted March 11, 2015 Yes a copper crush washer and you can kiss it with rtv just don't go crazy Quote
sleeper06 Posted March 11, 2015 Report Posted March 11, 2015 I've seen them stretch the cam chain and jump time also Quote
draggins10 Posted March 11, 2015 Author Report Posted March 11, 2015 Alright thanks guys. I'm going to try steps #1-#3 but most likely end up doing step #4 haha Quote
draggins10 Posted March 11, 2015 Author Report Posted March 11, 2015 175 main, 48, pilot ncvq needle 4 th clip , air screw 3 turns out, I doubt it's the jetting,if u sprayed the the carb slide with cleaner the oring expands and fucks throttle opening, my suggestion would be #1 leKdown test to make sure valves are sealing at tdc #2 check valve lash I'll bet dollars to donuts that where the problems lie , need to re shim valves before you damage something #3 make sure your excellerator pump is skirting fuel good #4 all else fails drop it off lol I've built some killer 450s Alright thanks guys. I'm going to try steps #1-#3 but most likely end up doing step #4 haha Quote
sleeper06 Posted March 12, 2015 Report Posted March 12, 2015 Lol I'll see you this weekend , I have all the master shim kits for these bikes so let me know Quote
sleeper06 Posted March 12, 2015 Report Posted March 12, 2015 Also if someone tried doing a cam mod to this thing and did it wrong it would cause issues your talking about Quote
draggins10 Posted March 12, 2015 Author Report Posted March 12, 2015 Also if someone tried doing a cam mod to this thing and did it wrong it would cause issues your talking aboutIt looks like he rotated intake cam instead of exhaust cam right? Quote
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