..valve adjustment..

[wordslinger]

..okay, so just when you think you know your scoot, you find something that makes you go hhhmmm......

..adjusting my valves last evening, and EVERY time before, that i adjusted them, the cearance was ALWAYS too great, and needed to be decreased...

...THIS time, when I checked the clearance, i could not even get my thinnest feeler gauge in the gap...

..I could feel NO play in the rocker arms..

..anybody got any thoughts as to why this might be???

[Hoolander2]

Just the usual things you'd think of.  Motor was still warm -- or at least it wasn't as cold as it was when you last adjusted. 

Or, valve seats or seating area of the valves themselves are wearing down.

[Hoolander2]

Oh, and also, maybe cam bearings are wearing, allowing cam to ride closer to the head?  Well, no, guess that'd make the gap bigger.   Umm, worn rocker arm bushings? 

[zombie]

I believe either of the first 2 are correct. It was most likely around freezing when they were done last...  try it for a another 1/2 as long as you normally wait to adjust, and re-check them. If they are worn in again, it will give you some time to find some really good hardened seats, and three angle valves.

[axy]

I know that you are valve-adjusting freak.
The two pics below are great, it would be good if you could describe a bit what has to be removed in order to gain access to valves.
Also, where could one have problems doing that.

One more thing... the gap is very small, I do not have manual at hand, but it's something like 0.0005 mm or something...
The thinnest feeler I have is something like 0,05 mm...

Where did you get adequate feelers?

Thanks...

..okay, so just when you think you know your scoot, you find something that makes you go hhhmmm......

..adjusting my valves last evening, and EVERY time before, that i adjusted them, the cearance was ALWAYS too great, and needed to be decreased...

...THIS time, when I checked the clearance, i could not even get my thinnest feeler gauge in the gap...

..I could feel NO play in the rocker arms..

..anybody got any thoughts as to why this might be???

[wordslinger]

I know that you are valve-adjusting freak.
The two pics below are great, it would be good if you could describe a bit what has to be removed in order to gain access to valves.
Also, where could one have problems doing that.

One more thing... the gap is very small, I do not have manual at hand, but it's something like 0.0005 mm or something...
The thinnest feeler I have is something like 0,05 mm...

Where did you get adequate feelers?

Thanks...

..the gap on my A50 is .04mm


..imma mod those pics with some arrows and captions..then i'll repost them with some guidelines...good idea axy!

..i get my parts guy at work to gt me my gauges...i think he gets them from MSC, or McMaster-Carr...

[wordslinger]

I believe either of the first 2 are correct. It was most likely around freezing when they were done last...  try it for a another 1/2 as long as you normally wait to adjust, and re-check them. If they are worn in again, it will give you some time to find some really good hardened seats, and three angle valves.

..i'm pretty sure that the ambient temperature was probably close to being the same...set them with the scoot indoors last time..and outside on th porch this time...scoot was cool to the touch both times...

..all bearings and bushing are in great shape...

..valve seat wear...or wear on the top side of the valve...i think that might be the answer...

..I guess after 43,000 km, i can expect these sort of things to start popping up....

...three angle valves?

[Kimcofan]

This may sound stupid considering you have been giving me all the advice, but was your piston set to top dead center when you adjusted?
Straight from the manual:

Turn the flywheel counterclockwise so that
the “T” mark on the flywheel aligns with the
index mark on the crankcase to bring the
round hole on the camshaft gear facing up to
the top dead center on the compression
stroke.

Dumb right?...Oh well....LOL

[wordslinger]

This may sound stupid considering you have been giving me all the advice, but was your piston set to top dead center when you adjusted?
Straight from the manual:

Turn the flywheel counterclockwise so that
the “T” mark on the flywheel aligns with the
index mark on the crankcase to bring the
round hole on the camshaft gear facing up to
the top dead center on the compression
stroke.

Dumb right?...Oh well....LOL

..not dumb at all, but yes...it was TDC...

[Kimcofan]

Well you have me stumped, the Temperature suggestion seems like it might have been the problem.  Did you readjust the valves anyway and if so how is it running now?

[zombie]

Three angle valve jobs are the standard for ALL racing/hi performance engines. Your valve seat will have 2 at the most. The idea is three seperate sealing surfaces w/ reduced angles at the ends of the seats. the reduced angles allow the valve to run cooler, and seat tighter. If you have a good machine shop near you they will be able to locate, install, and taper hardened seats, and match your valves to them. I would think 75-100 bucks would be on the high end estimate.

[wordslinger]

..oh, yeah...had to adjust them..with no clearance, you can't be sure the valves are closing off completely...

[wordslinger]

Three angle valve jobs are the standard for ALL racing/hi performance engines. Your valve seat will have 2 at the most. The idea is three seperate sealing surfaces w/ reduced angles at the ends of the seats. the reduced angles allow the valve to run cooler, and seat tighter. If you have a good machine shop near you they will be able to locate, install, and taper hardened seats, and match your valves to them. I would think 75-100 bucks would be on the high end estimate.

..sweet...guess i'd better start looking...

[Hoolander2]

Axy.  Probably the two biggest mistakes one can make in adjusting valves are:

1. Not letting the motor cool completely before adjusting. This results in a false reading of the gap.

2. Adjusting the gap too small -- this can happen 2 ways.  One can mis-judge the feeling of the feeler guage.  Or, one gets the gap correct, but then when the lock nut is tightened, the gap changes.  Therefore, it is always reccomended to re-check gap after tightening the lock nut.

If the gap is set too small the valves will "burn" or bend.  They need to be in contact with their seats for a certain amount of time during the cycle in order to transfer heat to the head.  If they don't, they stay too hot.  Damage can be done instantly!

Too tight can also damage cam, rocker arm, valve, and more, by putting too much pressure on the entire mechanism.  

[wordslinger]

..well spoken hoolander...