Quickly checking valve clearances without re-installing cam chain

I am just redoing my valve clearances for the first time on the bike. I had two inlets under spec, one inlet on the lowest limit, one exhaust below spec and one right on minimum. To be honest I was a bit peeved as the bike has only done about 1500kms and is meticulously maintained. I have calculated what size shims I need to put each valve back in the middle of the specs.

I am hoping that I have got it pretty spot on with my calculations, as I don't want to have to buy even more hims if it isn't just right.

Am I able to accurately perform a quick measurement of the clearances without having to re-install the cam chain and tensioner. Provided that the cams are in the correct position/alignment and bearing caps bolted down, I assume that the cams will be in the position of least resistance ie TDC

Also, when re-installing the cam chain, provided the TDC marks are lined up, the cams "punch marks" line up horizontally, is there any other tricks to ensuring that everything is lined up properly? I am getting paranoid I could be out on the timing .:thumbsup:

YES - Install cams and torque to spec - point lobes to the outside of the head and measure clearance - you don't need the cam chain for checking the clearances.

You should have marked your cam chain and gears with a grease pencil at TDC before disassembly - it's foolproof.

You should also get a new cam chain - cheap insurance.

What you said will work, just take both cams at the same time - point the gear down and in on both, slip them under the chain and set them in their appropriate places - a second pair of hands here really helps, but it is doable by yourself.

You should have marked your cam chain and gears with a grease pencil at TDC before disassembly - it's foolproof.

I shoulda....but didn't :thumbsup: This is what I followed from the manual. Hence not marked.

Adjustment steps:

Loosen the timing chain tensioner cap bolt.

Remove the timing chain tensioner and camshaft caps.

NOTE:

Remove the camshaft cap bolts in a crisscross pattern from the outside working inwards.

Remove the camshaft (exhaust 1 and intake 2).

NOTE:

Attach a wire 3 to the timing chain to prevent it from falling into the crankcase.

Whoops! Looks like now I am up that certain well known creek without a paddle then. If I was a religious man, I would be praying to my deity right now for some guidance.

By the way, Matt, thanks for the quick and helpful reply. :thumbsup:

I wouldn't bother checking it without the camchain in place. If you check it without the camchain and it is good you then have to take it apart to put the chain back on. If you alread had the chain on and it was good then you would be done. Bottom line is if you check it without the chain you definately have to take it apart again. If you check it with the chain you have a 50/50 chance that you are done.

Mr Bean,

You raise a good point. I need to be confident that all measurements and calculation of shim sizes are correct and get it right first time.

Once the cams and timing chain are installed (without the tensioner installed) is there enough slack in the chain to be able to slip a tooth on the sprocket, if by chance the alignment of the cams, and timing mark are out. This is really my main concern, due to not marking beforehand as Matt suggested.

Whhops sorry, I gotta be confident! Everything is fine. All is good. Hey, I think the positives thoughts are working already. :thumbsup:

Also the manual mention using molydenum sulphide grease on the cam lobes. Is this really necessary? I was just going to ensure all parts were well lubed with engine oil.

OK, it takes all of 1 minute (less actually) to bolt/torque down the cams WITHOUT the chain, and all of one minute to remove them again, yet every time you have to install them WITH the chain on, you risk scoring something because of the nature of the install (angled down and inwards then tilt them into their respective places while trying to set the timing chain on them and getting the teeeth in the right places - about a 5 minute install if you're good at it and 15-20 if you're not). :thumbsup:

When doing it without chain there is NO risk of damage so why NOT do it that way first???? At least you know you're only going to mess with trying to get the chain on once when you already KNOW your shims are at the right clearance.

And to your question about slipping the chain on after - not a chance!!

Just make sure your engine is exactly TDC before installing cams/chain.

Your cams have little dots on the sprocket, you want the lobes facing outwards, the dot on the exhaust (far left) and the dot on the far right (intake) should be just a hair above the machined surface where the cover/gasket sits on, not below and not above, pretty much right on, that's about the best way to explain it to you without a pic.

The diagram in your manual sort of shows it, of course there's nothing like a photograph!

Matt. Well explained.

When the manual says to untighten/tighten cam bolts in a criss-cross pattern, is it like what I will attempt to display below?

1 3

6 5

4 2

The numbers are the sequence in which the bolts in that position on the cam holder thingy, are tightened. Is this correct?

I forgot to mention that on my wr450F, the timing mark that aligned up all the cam punch marks was actually the middle mark of three verticle lines spaced about 1/4" apart on the flywheel. This was a bit of a concern as I was expecting a single mark, but as everything lined up as per the pics in the manual, I thought this was fine. If I have done something wrong, can someone PLEASE TELL ME NOW before I do some damage when re-assembling the whole mechanism.

I tighten them (using your number layout as bolt labels) as shown but my sequence of numbers to follow:

1 5 4 6 3 2 first snug, then repeat to torque, then repeat to verify- it doesn't leave you a big gap between bolts doing it that way.

Set your torque wrench a little lower than spec (about 5%) it's been known to cause noise if at spec or slightly higher.

When you were first pulling it apart and checking clearance it doesn't really matter exactly what one of those marks you used for TDC - they're all within a few degrees and your lobes are far enough away at that to do a proper clearance check. when re assembling, use a long socket extension in the spark plug hole, when you rotate the crank, it will come up, hold position for a bit (TDC) and drop again - the mid point of the "hold position" is exact TDC, you can then look though the hole and see which mark it is supposed to be and write that down (draw it out) for the future.

When doing it without cams in, just have someone pull up on the chain and feeding it as needed back and forth as you rotate the crank to find TDC - this will assure the chain doesn't jam down below.

Must you guys make such a project out of everything?

I throw a little 2 stroke oil in my gas and never have to adjust valves.

Everytime I check it's fine.

haha - you're just jealous - otherwise you wouldn't be in here looking!

My Uncle Arnold from Sasketchewan says people from Ontario think they know everything.

I keep my air filter clean so I never have to adjust valves.

I don't have the manual in front of me but does'nt it state to rotate the motor a few times by hand after adjusting / re-shimming, then re-check?

I don't know what difference it makes but I would want to know that my valve clearances are spot on once I have my cams, chain and tensioner in place with proper timing:excuseme:

Again, I don't know what difference it would make, all I know is that I get nervous when I veer from the text in the manual... If the crank timing mark is at TDC and the dots on the cams are aligned with the top of the head and the cam lobes are pointing out you should be good to go... understand that the cams will likely rotate a small amount one way or another when everything is installed and timed but how much movement at that point does it take to change the valve clearance?

Your Uncle Arnold should just stick to plowing his fields. :thumbsup:

Your airfilter has little to do with adjusting your valves, even changing it out every 2 minutes will not stop you from having to adjust valves on a 4 stroke at some point in it's life (sooner if you own a Honda).

And no, we don't know everything, but unlike people from Jersey, we try to help when someone asks! :thumbsup:

Uncle Arnold is probably plowing right now. Then he goes and chases squaws around at the local beer joint.

BTW I bet this is your first bike isn't it?

And all the guys with great personalities come from NJ.

Guys like me and Jason Lawerence.

yes, probably yes

no

no

Jury's out on that one. :thumbsup:

Your airfilter has little to do with adjusting your valves, even changing it out every 2 minutes will not stop you from having to adjust valves on a 4 stroke at some point in it's life (sooner if you own a Honda).

Only the newer Honda racing thumpers have maintenance-intensive valvetrains. Other Hondas are really good on valve life/adjustment intervals.

Only the newer Honda racing thumpers have maintenance-intensive valvetrains. Other Hondas are really good on valve life/adjustment intervals.

I'd like to know where you heard that, everything I have seen about Honda thumpers, they didn't resolve their valve issues until 2006 model year (which makes the newer racing thumpers a little less intensive) - they were using valves a lot lighter than the rest of the industry - but running those valves caused longevity issues - every guy in our club running 02 to 05 Honda's has had repetitive valve problems and after replacing with stock valves a couple of times, most have now finally switched to SS valves to help combat the problem.

If you're talking the XR's, that's different - they do not fall in the same category as these bikes, but that would be like comparing apples to oranges and the shims wouldn't fit anyways

I'd like to know where you heard that,

Why, from Uncle Arnold of course. In Sasketchewan.

^^^^:thumbsup: :thumbsup: :thumbsup: :thumbsup: :bonk: :bonk:

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