Completed Overhaul: WONT START

[chuck hahn]

I havent installed or used new ones. I have used the Neway cutters and recut the existing ones though. I was assuming the new ones would come precut. I am still learning many things as the need to fix whatever it is arises.

[almarconi]

Here is a link to how they are installed in a car head, the procedure should be similar to a motorcycle head:

http://www.cheprecision.com/html/install2.html

[chuck hahn]

The yamaha manual for the TX tells you to heat the head in an oven for even heating. This expands the aluminum faster than the seats metal and they can be removed that way.

[Maddevill]

Heres how to determine why your compression is low. Using the nut on the right side of crank turn until a piston is at TDC compression stroke,(valves closed). Using the adapter from a compression gauge, put air into the cylinder. Don't go too high on the psi, hold the crank from rotating with a wrench. If you hear hissing from the exhaust, your exhaust valve is not seated. If you hear hissing through the carb throat, your intake valve is not seated. If you hear air through the crankcase breather your rings are not seated or are broke.

[Starion007]

With the lapping of the valves even though you may not have ground them it can still tighten up the valve lash. I would go and check the valve lash clearance. I have found after a head reassembly the valve lash gets smaller after the motor is cranked over or run.
I put one back together with the lash on one valve less than the minimum and after starting it and running it the lash went to zero, and I had blow by and low compression on that cylinder.
Worth a look.

[Call Me Ahab]

Okay. So, I'd like to invite you all to kick my dumb ass.

I had not timed it correctly. Not even remotely. I was timed off the 2,3 cylinders, "F" mark, I think it is. The plate's too damn dirty to see clearly, I was pulling off the contact breaker plate thing whateverthehellucallit when I realized what was wrong.

I'm a ****in moron. After I timed it (CORRECTLY THIS TIME) the compression reads 120 + !!

I was ecstatic - I took my time, got everything cinched back down, put my valve cover back on etc etc... It actually f'ing fired up. No choke, first push. Runs strong, no misses, perrrrrrfect...

Now, I have a new problem. It idles high. Like really freakin high. I can't figure that one out. But, I've made progress tonight, and I am tired. I'll deal with that issue tomorrow.

I loosened off the throttle cable completely, still runs high - disconnected choke cable from the carb body, no effect. Didn't tinker with the idle screw though... Probably should have.

So - valves are indeed all right, no leaks at all intake or exhaust now.

I do however have like 4 oil leaks. I'll sort that out tomorrow too. And on that note, do I really need copper washers up top, under those dome nuts?

Oh, one last thing - clutch drags.

All this is easy fixin', so I'm going to take my time and do it all right. I'll have to synch my carbs using the uber-****ty amazon.com 2 barrel mickey-mouse piece of crap that I have. Unless someone local can rent me a good one. Need to fine tune fuel mixture screws too... But that high idle puzzles me, unless I really have that idle screw set high?

Anyways, I'd like to express my gratitude to everyone who offered advice and assistance here! I'm terribly sorry that I wasted your time with such an asinine mistake. I wish I could say it won't happen again... But I told my father that years back about **** catching fire, and look where that got me.

Good night guys, and thank you all again!

[chuck hahn]

Loosen the jam nuts at the carbs and see thatb there is just a whisper of slack in the cables as you twitch the throttle grip. If it still is high, turn the big knob in the center counter clockwise and see if it lowers the rpms.

You can also make a little slack up at the bars with the adjusters there for the cables.

[storm 64]

Experience is a wonderful thing,
It enables you to recognize a
mistake when you make it again...

[chuck hahn]

Better yet on the high idle...


Loosen the jam nuts at the carbs and start the bike. Adjust the idle with the big idle knob and then lock down the cable adjuters.

Be sure the engine is warmed up so it is reading a warm idle. Set a house fan ( or 2 ) in front of the engine to blow cooling air across the fins while she is warming up good.

[Call Me Ahab]

Loosen the jam nuts at the carbs and see thatb there is just a whisper of slack in the cables as you twitch the throttle grip. If it still is high, turn the big knob in the center counter clockwise and see if it lowers the rpms.

You can also make a little slack up at the bars with the adjusters there for the cables.

Better yet on the high idle...


Loosen the jam nuts at the carbs and start the bike. Adjust the idle with the big idle knob and then lock down the cable adjuters.

Be sure the engine is warmed up so it is reading a warm idle. Set a house fan ( or 2 ) in front of the engine to blow cooling air across the fins while she is warming up good.

All righty ; I'm getting ready to head out there now - I need to reset my fuel mixture screws first, then I'll back off on the idle screw, then I'll fire it up... This far in, I'd be destroyed if something blew up on me now!

Previous Owner complained of high idle too.. but then he's the one who jerry-rigged all of his repairs, coated this thing in a dozen coats of off-the-counter spray paint, and used auto vacuum lines in place of the fuel line. That doesn't work, by the way. The ethanol in the fuel eats that up, along with the lawn mower in-line filter he plugged into it. And the teflon tape he wrapped around the #3 plug after he stripped it out. Oh, and the self tapping screws he used to hold the exhaust to the frame... And using 4 different boots on four different spark plugs... and gapping them all wrong... Oh lord, I can keep going but I better stop.

Thanks guys! Forgive my foolishness.

[Call Me Ahab]

Okay! That did the trick, but I've got oil leaking out through the bolts that hold the head down. A good deal of it too...

I replace the OE nuts and washers with stainless washers and some serrated flange nuts - do I need to go back with cap nuts and copper washers? I think I see why those copper ones were on there to begin with... My guess is they act as oil seals? Is this correct?

[almarconi]

My guess is that you probably don't own a torque wrench. Head bolts need to be torqued down a certain amount. Is the oil coming out of the valve cover or from the head. You could have a crack in the head. Best to clean everything off, replace the head bolts/nuts with the correct fasteners, properly torque them down and see what is leaking.

[Starion007]

Okay! That did the trick, but I've got oil leaking out through the bolts that hold the head down. A good deal of it too...

I replace the OE nuts and washers with stainless washers and some serrated flange nuts - do I need to go back with cap nuts and copper washers? I think I see why those copper ones were on there to begin with... My guess is they act as oil seals? Is this correct?

You are correct, the 4 on the ends.2 on each side act as oil seals under the head nuts. Change those out and use a torque wrench. I doubt its cracked, there pretty tough.
On a side note the 4 on the outside of the cam tower might be copper also, check your manual or google it.

[azr]

I 'thought' they were all copper but I could be wrong, the outer ones are for sure. Hey what kind of compression do you have after your top end rebuild?

[Starion007]

Glad you figured it out, I remember when I put one together I put a 4 valve timing rotor on the 2 valve motor by mistake. Kicked my but for a couple days till I figured that out, now I tag and bag small parts!!