Other Honda Xr350r Timing

M

MrHonda350

ossagp:
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.
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I'll post a pic in a bit. I tried to start it with fuel etc. is there any tricks or tips to checking the sealing. How do you cut the seals and valves? I'm new to these kind of things so thank you for all your help.
 
O

ossagp

usually cutting the seats is a machine shop job. to get a good job done they either have to knurl the guides to bring them back to "round" and to spec, or replace the guides then cut or "machine" the seats.

you can do a compression test, bleed down test if you have the gauges to do that. If you have an air compressor you can use a rubber tipped spray gun that will seal at the sparkplug hole. you just put it on topdead center and run the compressor up to about 50 lbs and see if you are losing air out of the intake or exhaust (made easier without the pipe and caburetor installed). If you dont have any of those handy, a small penlight held in the spark plug hole at tdc, with measureable valve clearance and the lights off will allow you to look down the intake and exhaust for rays of light.

if you want to use the compressor etc to check for leaks, soapy water works to find which side etc.
 
M

MrHonda350

ossagp:
usually cutting the seats is a machine shop job. to get a good job done they either have to knurl the guides to bring them back to "round" and to spec, or replace the guides then cut or "machine" the seats.

you can do a compression test, bleed down test if you have the gauges to do that. If you have an air compressor you can use a rubber tipped spray gun that will seal at the sparkplug hole. you just put it on topdead center and run the compressor up to about 50 lbs and see if you are losing air out of the intake or exhaust (made easier without the pipe and caburetor installed). If you dont have any of those handy, a small penlight held in the spark plug hole at tdc, with measureable valve clearance and the lights off will allow you to look down the intake and exhaust for rays of light.

if you want to use the compressor etc to check for leaks, soapy water works to find which side etc.
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I did a compression test and got 150 lbs of compression. If my valves do leak is it possible to have that high of compression?
 
O

ossagp

yes it is possible. 150 on an xr 200 or 250 would be a good 40 lbs low. Considering you are running a new machined item against a a surface that is not only worn but probably had "edge" contact, it would be hard to imagine that you are getting full compression. you may still have enough to run, there may be other issues keeping it from starting.

And when you put the cover with rockers back on you have play/clearance at the valves?
 
M

MrHonda350

ossagp:
yes it is possible. 150 on an xr 200 or 250 would be a good 40 lbs low. Considering you are running a new machined item against a a surface that is not only worn but probably had "edge" contact, it would be hard to imagine that you are getting full compression. you may still have enough to run, there may be other issues keeping it from starting.

And when you put the cover with rockers back on you have play/clearance at the valves?
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I'll try to grind the valves. When I put on the cover with the rockers I do have play at the valves
 
Mihylo33

Mihylo33

MrHonda350:
I'll try to grind the valves. When I put on the cover with the rockers I do have play at the valves
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Do you have a service manual for this or are you winging it via internet and Chuck from Napa?

If you don't have a manual please get one. It will make your life easier as well as making it easier for us to help you.
 
2strokesteve89

2strokesteve89

Mihylo33:
Do you have a service manual for this or are you winging it via internet and Chuck from Napa?

If you don't have a manual please get one. It will make your life easier as well as making it easier for us to help you.
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timoyz:
His name is Mr. Honda. He doesn't need no stinkin manual.:picard:
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You guys have it all wrong, Mr Honda dude actually has Manuel from Honduds fixed rite helping him. So......lay off the guy.
 
snowflake

snowflake

why not just guess.

When properly timed none of the valves will be open, it looks like you found the marks, just verify that the crank is at TDC and that the cam is not opening any valves.
 
O

ossagp

MrHonda350:
I'll try to grind the valves. When I put on the cover with the rockers I do have play at the valves
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Grinding the valves is NOT what you do with stellite coated valves. (the manual would tell you that). you seem to like taking target practice on your feet.

Anyway, your rig doesnt seem to be holding pressure, which like i said would be surprising. Even though your xr is not a 12,000 rpm crf250, it is light years ahead of a flathead continental/studebaker/kaiser jeep offering. when you have seats that ARE out of round you don't gain much and for very little time.
 
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