Okay before you tear strips off me for asking about a topic thats been posted to death, bear with me :O)

I was reading pages and pagesof valve adjusmentarticles here on the forum, and someone mentioned that not only can your valve adjustments be too loose (tapping) but also to tight. Having a too tight condition appearenly causes valves to burn? (this is what I gathered from the conversations.) Now I can understand over time wear is a issue causing a "tap". But how would a valve "tighen" to the point where it would have to be back off. Has anyone adjusted their own valves?? and if so how many of the valves needed to be backed-off opposed to tighened. The reason im asking is I dont have any tapping noises currentlyand I dont want to waste time/money on the valves if it is not necessary. If it ain't broke, don't fix it sorta deal.....

TIA

 

I stand by what I said in the beginning - while adjusting the valve lash may make the bike run smoother, or start quicker, if it ain't broke, don't fiddle with it........especially if it's running well......

 

It is quite normal that the valve lash becomes smaller over time on these and similar engines. The reason is that the valves and valve seats wear and the valve thensuccessivelymoves higher up in the cylinder head. I some point the lash will become so small that the valve never close when the engine is cold and the bike becomes very hard to start when cold. To little lash will also mean that the valve is open longer and not cooled as well by the seat.

 

R1000, thanks for the insight - but I'm confused - how can a valve move progressively higher into the seat, without adjustment ? I can understand that over time, a valve may wear in its seat, making the clearances too big and causing poor valve closure, bad starting and compression loss, but moving up on its own ? I don't understand.

 

I agree Shadow. So , has anyone done their own valves here? I understand the reason behind valve adjustment, I was just curious if the majority of the valves,that are adjustedwould betighend up or are they backed off to achive the proper clearance?

BTW, I adjusted by balance shafts today and installed a cigarette adapter for my GPS. Everything went great, even squeezed in a oil change to boot. Figured I'd try the AMS oil this time.

 

I agree with R1000, valves do tighten under some circumstances. Think about seating rings in. The rings expand into the walls as the high points quickly ware. The same happens to new valve seats. The high points wear and the valve moves higher up into the tapered seat. On new engines it is important to check the valve lash at the break in mark. This is when you will most likely find the tight ones. After the engine has racked up some miles the ware is usually up top in the cam to rocker or shim area. Poor oil and lack of changes will tend to show more ware up top then at the seat. High rev-ing engines would see a little more wear at the seats also as they are slamming shut rapidly.

OK! Now think of a cutting torch. One wicked hot flame cutting metal; this is not to dissimilar to the hot exhaust gas exiting the exhaust port at a very high speed. The only thing cooling the exhaust valve and keeping it from melting is it’s material and the time it spends sitting on and making contact with the valve seat. Heat is transferred from the valve face to the valve seat only when the valve is closed. The valve spends more time open then closed and actually spends very, very little time seated. This is why a loose lash is better than a tight one. The intake gas passes over the valve face and cools the intake valves and this is why intakes usually have tighter lashes; they can stay open longer without harming the valve.

Gill, you can become a AMS dealer and deal to yourself, ask them how.

 

Did them, took a bunch of pictures, and did a right-up for doing them:

https://cbrforum.com/m_364190/tm.htm

 

I'm not sure I agree with your thinking. Given that these are 4 cycle engines, an intake valve is going to be closed during the compression, power and exhaust strokes. That's roughly 75% of the time. Certainly having more or less valve lash is going to effect the amount of time the valve spends in it's seat, but I'm not sure it's going to make that much difference. That being said I figure if Honda thinks that the valve lash should be adjusted every so often, then that's probably the best thing to do.

 

Okay, so that being said, malbojahdid you find most of your valves out of adjustment too much, or too little? I didnt mean to get into a big debate about valve adjustment, all I wanteed to know was the type of adjustments being made. I must thankyou for the time you took to take those pictures by the way. They were extremely helpfull )

 

I always adjust my own valves. Due to seat wear & the effects of using my bike primarily for commuting ie. low speed/high temperatures, I have found that I get better results setting all the valves 1 thou loose. On a cold start up there is a "slight" ticking but as the motor warms the clearance tightens & it all quietens down. It's almost comforting to hear it all work as you know you're not burning valves.