Hi, I recently purchased an 1983 Honda Xr350r for $200, nonrunning. The guy said it needs a head gasket and maybe new valves and it may be out of time. I got the head gasket and new valves and now i am wondering, how do I get it to the correct time since i didnt have anything to go by the first time?
Other Honda Xr350r Timing
- Thread starter MrHonda350
- Start date
Welcome to the forum. The Mr Honda moniker may be somewhat lofty judging by your question but I'll cut you some slack. When you say you got new valves you mean they are in a box or in the bike? If you installed them already then you are way ahead of yourself. If you don't have a manual, be very careful not to overtourque the cap bolts, and as a general rule you line up the marks on the cam gear with the head surface, and the tdc marks on the rotor and case cover. Good luck on that classic bike it was fine machine, made good power and was lot of fun to ride.
I ordered new valves online. The ones in the bike were bent slightly. I installed them and the head gasket and head, now I'm on to timing. I got the torque specs online already and have the head bolts torqued down. I put the flywheel at TDC and I lined up the marks on the cam sprocket with the head. And I tried to start it but when I did it just blew air out of the carb when it would fire. So I'm wondering am I 180 degrees off in my timing?
Did you catch the part about the lobes facing down?? Piston at TDC, lobes facing DOWN. Rember the cam turns at half the speed of the crankshaft.
Make sure you have the right valve clearance at that point. If you don't have MAXIMUM clearance right at tdc (lobes down) then you are not in time, likely a tooth or two off. Those fire each time the crank goes over, so you get it trying to light. Clearer now?
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I rotated the cam 180 degrees so when the spark plugs ignites the lobes are facing down (I took a slow motion video so that's how I can tell) and it's still puffing air out of the carb. Any ideas on why this might happen?
yeah, they aren't closing all the way. I only have one xr currently that you can do as you say get "180" out. the others (and I dont have a 350) make a spark each time the piston goes to tdc(slightly before it at the F mark if all is well). Is this coming across? my guess is that if you have actual valve clearance at tdc that either your valves bent again, you are off on the cam timing a bit, or you didnt cut the seats to match the valves. all that is really easy to check.
I adjusted the valves right away so they are adjusted right (weather or not they are seating). Do you want me to send a pic of the cam and its timing marks at TDC? I didn't cut the seats to match the valves when I got the valves either. I'll start at timing and then go to the valves not seating.
post a pic if you want. are you just kicking this one over, or did you actually try to start it with fuel in it etc?
I think before i played anymore timing games, I would check for the valves sealing. if those are genuine they are stellite tipped and don't do will with "grinding". the seats need to be cut to match. especially if it had vavles bend against the existing seats in the past. guides are a more minor concern. half a head rebuild can bring this on. usually just having the simple cast iron seats cut if you still have straight valves should get yours sealing up enough to run and get your money's worth from.
I think before i played anymore timing games, I would check for the valves sealing. if those are genuine they are stellite tipped and don't do will with "grinding". the seats need to be cut to match. especially if it had vavles bend against the existing seats in the past. guides are a more minor concern. half a head rebuild can bring this on. usually just having the simple cast iron seats cut if you still have straight valves should get yours sealing up enough to run and get your money's worth from.