Servicing Valve Clearances...

[Sid Squid]

Read this:

Originally Posted by Me!

The valve clearance check is scheduled every 15,000 miles, so at 20,000 miles it's slightly overdue, yes it is entirely normal to find some clearances out of tolerance - that why it's a scheduled check. That said the SV is known for not needing a lot of adjustment, that doesn't mean it's never needed though.

Generally speaking exhausts close up and inlets open a bit, so your finding the exhausts a little tight is not something that can be ignored. As you're going to be removing the cams I'd reset everything to as near the middle of the allowable range as is possible, that way it's odds on the longest period until it needs doing again.

Every time the inlet valve opens it receives a nice cooling rush of incoming gas, and when it's closed it dissapates heat through the valve seat, even though that's a small area for conducting away heat - every little helps - in short the valve itself has an easy life, and thus wear in the opening mechanism commonly outweighs the wear to the valve - thus the clearance often opens up a bit. Exhaust valves however don't have such an easy time, they get and stay very very hot, their primary way to dissapate heat is the thin ring of the valve seat, and a little up the stem, everytime the long suffering exhaust valve opens it gets fried with gas at/near combustion temperature - typically 300-700C - thus in the case of the exhaust, the valve tends to wear more than the opening mechanism, hence the clearance reducing.

Also we have a nasty Catch 22 - if the clearance becomes significantly reduced, (or worse still if there's no clearance and the valve never fully closes), the valve spends less of the already small amount of time that it should do closed, thus it never disspates the heat it should do and can literally melt, this is called burning a valve, no surprise there, and you really don't want to get into that.

A round of applause for your exhaust valves please - the hardest working bit of your bike, full stop.

Ah well, not too much to worry about then, not even at 9000 miles yet. I'll probably crash and write the thing off by 15,000 miles.

I just spoke to an SV mechanic in a central London bike shop who said that they have done loads of checks but had never an SV650 that needs adjusting! If they needed adjusting the noise, apparently, would make it obvious. He said they are very solid motors...

[jambo]

Originally Posted by joeheaven

I just spoke to an SV mechanic in a central London bike shop who said that they have done loads of checks but had never an SV650 that needs adjusting! If they needed adjusting the noise, apparently, would make it obvious. He said they are very solid motors...

The fact that the valve clearances on the SV motors need adjusting infrequently is well documented. You will never hear a tight valve though, and as documented above it's a very bad idea to put it down to faith that they're ok. Get it checked or check it yourself, chances are it'll be fine but lets not tempt fate eh?

Jambo

I'd like to 'move up' from checking all the easy stuff, and start checking the valve clearances. Is there a clear guide somewhere for doing this?
Jon.

Originally Posted by ujoni08

I'd like to 'move up' from checking all the easy stuff, and start checking the valve clearances. Is there a clear guide somewhere for doing this?
Jon.

It shows you how to do it in the service manuals, available to download from this site.

[TSM]

Originally Posted by joeheaven

I just spoke to an SV mechanic in a central London bike shop who said that they have done loads of checks but had never an SV650 that needs adjusting! If they needed adjusting the noise, apparently, would make it obvious. He said they are very solid motors...

For the peice of mind, get it done, should take you less than 1h to check them.

Mine at 20k ish, were all out, but my bike has not had an easy life. I need to do them again though as when i last did them afterwards the exhausts were a little tight, still in the correct range but not by much.

Flamin Squirrel, can you tell me how to find the manuals before I smash this laptop?
Jon

http://www.sv650.org/sv_manuals.htm

Originally Posted by SVeeedy Gonzales

Ah well, not too much to worry about then, not even at 9000 miles yet. I'll probably crash and write the thing off by 15,000 miles.

that is a great way to look at things