National Rider

[lefty]

Thanks BG.

Your tip for removing the valve was useful. Regarding the adjustment to the valve, I took a 1 x 3 piece of plastic lumber and drilled a 5/16 inch hole through it side ways in my press so I'm sure it was square to the stock. I put that in my vice and put the valve stem through it. I gently applied pressure from the bottom of the valve and ran a file across the other side, so the file was square to lumber and thus the stem. Worked very well. I attached a pic in case it's helpful to others.

[Arkie]

lefty:

make a mental note of the very little wiggle feel you have of your guide and the valve sometimes might have to be rotated by hand while holding a piece of brillo pad against the stem to clean off the oil skim. (for future when fooling with valves so as to get idea if guide and or valve stem is worn excessively, while the valve is being removed for inspection of all)

You may eventually run across a engine (small engine and automotive) that has good compression and leak down test is good, but it smokes, burns oil, will foul spark plug every once in awhile or quite often if engine idles much. All that is wrong is bad intake valve guide letting to much oil up the intake stem. (and or intake valve stems seals also bad)

On a engine with these symptoms the INTAKE valve guide may be out of specs. When you lift the valve you will see black on the bottom of the valve and watch for lots of carbon on top of the piston.

[lefty]

Thanks Arkie.

[lefty]

I'm reassembling this one and am a little confused with the head bolts. There are 3 long bolts. According to the service manual, the location of the long bolts is not consistent with the location that I removed them from. I'm confident that my notes are correct so either my engine is not specified or this machine was taken apart before and whoever put them back put them in the wrong place.

All bolts have been cleaned and threads on the head have been taped, as advised. Bolts fit very cleanly.

Since the machine has run and leak down was good. My first instinct is to put them back in the same place I found them. But I'm not sure.

Thanks

[bgsengine]

I'm reassembling this one and am a little confused with the head bolts. There are 3 long bolts. According to the service manual, the location of the long bolts is not consistent with the location that I removed them from. I'm confident that my notes are correct so either my engine is not specified or this machine was taken apart before and whoever put them back put them in the wrong place.

All bolts have been cleaned and threads on the head have been taped, as advised. Bolts fit very cleanly.

Since the machine has run and leak down was good. My first instinct is to put them back in the same place I found them. But I'm not sure.

Thanks

I would always just follow the manual if the bolt location is specified there - been a long time but I think it was the 3 long bolts go in around the exhaust valve corner of the head - Be cautious though if they had wrong bolts in wrong place, you may have trouble torquing them down properly unless you clean up the threads by running a tap all the way through - threads could be corroded lower down where the long bolts are supposed to run

[lefty]

Thanks BG. I thought that would be the advice. The good news is that I cleaned these holes well with a tap with little resistance. And the machine was well cared for. The bolts are running very smoothly. I was shocked at how nicely they came out and how well everything cleaned up. I'm able to put them down to the shoulder by hand easily. I've added a little anti seize to the exhaust ones as suggested. So I'll torque them to spec.

The weird part is that the long ones weren't anywhere near where they were supposed to be. Two of them were at the front where the tank bracket is. I think whoever took them off thought they should go there because the tank bracket raises the bolts up a bit. I'm surprised because I'm pretty sure I know who worked on it and they are a big local shop that has been around for a while here.

On a different subject, the control lever for the throttle cable has failed. I found one on Amazon for $14 but wanted to make sure I can get this running before I spent any money. Since this appears to be a necessary component for controlling the throttle, I was wondering if there was any work around to run without to see if I can at least get her running. It looks like the cable maintains a static throttle input. So I just can't remove it and expect a normal operation.

[lefty]

Well I removed the throttle and oiled up the cable so it would work manually with me just pulling and pushing on the cable. I just couldn't wait to give this one a rip. I started her up and she runs like a top, without any adjustment to the carb. I went 1 1/2 turns for both carb screws. I'm super happy about this one as I mentioned, she's a classic and I learned to mow the lawn on my dad's lap with this machine. Taking care of that intake valve sure did the trick. Thanks to all for the help with getting her running again. Like I said...the machine means a lot to me.

[lefty]

Everything is going well with this one but of course, there is one caveat.

When I start it cold, an enormous amount of smoke comes out the exhaust. Like....a hug amount. Fills my garage. But once after about 10 - 20 seconds it stops. I shut it down after about 5 minutes and started it again after about 15. No significant smoke.

Ran it for a bit and shut it down. Waited another fifteen or twenty and started again... no smoke. But if I let it cool down all the way....a huge amount of smoke. Whitish blue.

My limited skills say rings but I had a pretty tight leak down test on it. Valve guides maybe? Fuel mixture? I'm not sure but it runs great. Idles strong way down low...I can count the strokes. And runs super smooth at the top. I say given the circumstance, it's a victory and I can live with the smoke at start up but I'd love to know why. Or maybe I should just accept it...after all, it's almost 50 years old.

Thanks.

[bgsengine]

Smoke begins immediately? or does it take a little bit to start smoking after it starts?

Could be your breather filter (it's a nylon mesh pad much like a brillo pad that is built into the breather) is not all there (highly likely!) - it would allow oil to build up in your breather tube and drain back that way - Did you check the breather drain-back holes before putting it back together? (2 small holes in the bottom of the breather right near the gasket surface, would line up with notches in an OEM gasket, and point down when installed)

One thing you could try to eliminate that is - when you go to shut it down and let it settle overnight, unhook the breather tube from the air intake, and leave it set loose - you can probably block off the hole in the air intake (to keep out any dirt) with some black tape wrapped around things.. then start it up and see if she smokes - if not then you will also most likely find oil dripping out the breather tube - Only way to replace the breather mesh filter is with a new breather. but the drain holes can be checked and cleared

[lefty]

I'll check that tomorrow BG. Thank you. The smoke begins immediately but then goes away after 20 seconds or so.