Questions about Valve Maintenance

I'm considering buying a new 06' SV650S but I have some questions regarding valve maintenance. My friend was telling me a bit about everything you would have to go through if you were replacing the shims yourself. So, my questions are: Do you have to remove the timing belt to remove the cam shafts or can the belt just be loosened and then re-adjusted once you finish, how long does it usually take to take the measurements and replace the shims, and how much does it usually run to have valve maintenance done at a shop if you don't want to do it yourself? Any help is appreciated!

I've just done it. The valve clearances and replaced the shims.

It's VERY much something you can do yourself so long as you follow the directions suggested in your Haynes or clymer manual. I might have misinterpreted some process and bent a valve or two. But so long as you read through the instructions beforehand, visualize it and then do it....then fine. 2 hours maximum.

It is very easy to measure the valve clearances, very simple indeed.

Adjusting the shims, a little more involved but if you have a mate, its very simple and can be done within a few hours.

Timing belt = cam chain??

If so, you don't need to 'remove' it, no. You do need to loosen the tension in the chain though by either removing the cam chain tensioner or just get a friend to hold the tensioner right in so there is plenty of slack so you can remove the cam shafts.

I didn't read the instructionjs right and my engine is making a nasty clattering noise.

1st time round

Taking measurements - 2 hours
Replacing shims - 3-4 hours.

[BillyC]

Hi Maestro

First of all, the SV650 is hardly different from many other bikes, in terms of checking the valve clearances, and changing them if necessary. The main points are that it's only two cylinders, so only 8 valves to check... but it is two blocks, so two sets of cams to remove.

So, Instigator's response is perfectly accurate.

If you just want to check the clearances, you don't need to remove the cams, or loosen the cam chain. It takes about 1-2 hours to do, and involves dropping (but not removing) the radiator, and lifing the tank - oh, and removing the head covers.

If you want to actually change the shims, then there's a lot more you need to know, and do, but it's not rocket science. 3-4 hours is fine, if you've got the parts... Patience and preparation is the key! First of all, it's considerably easier to do if you remove the tank completely if doing the rear, and perhaps even the throttle assembly if doing the rear.

It also helps if you have an NWS or Abba type stand, so the rear wheel has no weight on it. The really bugger is getting to the chain tensioners, which are located under the throttle body for the front cylinder, and next to the rear exhaust outlet for the rear cylinder. They are painful to get to - make your life as easy as possible. Ball-ended hex keys are supposed to help, but I've no experience of them on this job.

Actually changing the shims is easy - you will need tippex, and alternative transport to go and buy the replacement shims where needed.

It is a process of tactics... having been through it once, I know how I'd prefer to do it now, what I'd record, and what order I'd go around in.


However, if you're not mechanically minded or able - I'd recommend that you do not attempt this at all.

Thanks for the info/advice guys! :)

Originally Posted by BillyC

It is a process of tactics... having been through it once, I know how I'd prefer to do it now, what I'd record, and what order I'd go around in.

Please share. (When/If you have the time)

We've all got our own way of doing things, but we can all miss out on how to do things easier.

This time has been horrific for me, trying to determine what this clattering noise is all about abd am now 95% sure I'm going to have to order 2 new valves (intake, rear cylinder).

[BillyC]

I guess I'd do something along the lines:

First, Assemble the necessary tools:

• Micrometer gauge - to measure actual thickness of shims
• Feeler gauges to measure the valve clearances
• Screwdrivers - always useful
• Decent socket set
• A low range torque wrench
• Hex bits for socket set
• New coolant if neccessary
• Something to drain petrol into
• A magnet on a stick - getting the shims and buckets out can be very tricky!
• A stool to sit on while you work around the bike - you're going to be there for a while
• Gasket sealant, possibly even new seals for the head covers.

Then, proceed along the lines of...

• Remove the tank
• Remove the radiator - drain coolant, probably about the right time to replace anyway
• Remove the airbox and throttle-bodies to allow access to the front cam chain tensioner
• Put bike on NWS stand
• Rotate engine for front clearances
• Measure gaps on Front cylinder
• Apply tippex marks to chain and cam wheel - for replacement reference
• Remove front tensioner
• Remove front cams
• Measure each of the spacers with micrometer
• Reassemble front cams and tensioner
• Rotate engine for rear clearances
• Repeat process for rear cylinder
• Review measurements - establish what shims can be moved around, and what size shims need to be purchased - this ensures you can buy as few as possible - they're about £6/ea
• Get in car and go and buy the shims required - take micrometer to make sure they're accurate
• Repeat above processes, this time replacing/swapping shims where necessary
  NB: the engine only needs to be in the correct position to measure the clearances, not to change the shims, so this time you can do both cylinders at the same time - given you've made the appropriate tippex marks on the chains and cams to know how to put them back.
• Reassemble cams and tensioners
• Rotate engine and measure gaps - record them again for future reference, and to make sure they're back within tollerances (this is a bit of a last-look-forward check)
• Reassemble bike - throttle body, airbox, tank, radiator, coolant, petrol
• Cross fingers, start bike
• While you're there, maybe do your throttle balancing too, and you'll have one smooth bike!

Of course, there's the more temporary solution of just changing one or two shims that are closest to, or out of tollerance... but if you're aiming to do the whole lot, back to middle of the tollerance band, then I think the above is possibly the way to go.

Bluepoof gives quite a good explanation here and the pictures can be useful... some of the text can be confusing though - too many explanations for each cylinder. If you actually mark the chain and cam when you take them out, then so long as you don't rotate the engine (you wouldn't need to), then they can go back exactly as they were!