Checked valve clearances today - need advice.

[clean]

Hi Guys,

finally got around to checking my valves today. I have searched the forum / done some reading, and come to the conclusion that there is varying opinion on the subject .


When I say "varying opinion" I mean where should we be setting the valves? at max? in the middle? on the tight end? is measuring in inch sufficient or should we be using a fine increment metric feeler gauge set?.....I for one don't have a clue


Anyway, my intakes were all at roughly .005 (basically in the middle of the spec) some were a little tighter for the .005 to go through, but it went though on all without "too much" force - .006 would not go through on any intakes.

The exhausts however were tight across the board - two at .005, two at .006 and the rest at .007


I wanted to get some ideas on what you guys think I should set the exhaust to? I have heard going to the max is best for longevity, but I have also heard its risky, and in worst case could cause a failure. this bike is basically going to remain stock with maybe an aftermarket exhaust - nothing crazy. I'm thinking .010 ?

or should I be getting myself a finer feeler gauge and re-measuring?

thanks for any, and all input.

 

[Kiwi Rider]

Ok, I'll start by saying I'm an auto technician by profession, have worked in the trade close to 40 years and am currently working at our local Suzuki/BMW motorcycle dealership here in ChCh NZ.
The valve clearances I've always used thousandths of an inch feeler blades as that increment is fine enough, always has been, (before mm) always will be.
Any measurement that is within the spec set by the manufacturer, whether it be at the tight end or the wide end of the range of allowable and SAFE clearance, is good to go with.
This is how we are trained and it's never proved to be a problem.
I believe you are starting to look too deeply into the clearance issue, too pedantic about where to be within the specified range.
If you want to spend hours setting then rechecking and then setting again, and rechecking until you get it exactly to the thousandth of an inch, that's your time wasted, not mine, to remove and re-install the cams and set the valve timing correctly takes a fairly long time, apart from the wear and tear on the threads for the cam journals.
So for me, I only want to remove and install the cams ONCE, and if the calculations for the correct size shim to give me the clearance I desire works out to be a couple of thou out . . . so be it, I'm not sweating about it.
Providing it's within the range specified, it's good to go.
I recently replaced the camshafts in my '99 Busa and it all went well with the calculations for the clearances and the shim selection......thank goodness!
So I wish you all the best in your quest, Kiwi.

 

[Berlin Germany]

hi @clean

for street used busas
pls. read this post fully and fussyly to its end.

and get the manual for your busa gen 1 respectively gen 2.

then you don't have to guess (e.g. valve clearance value) but you can simply read .

 

[xc700]

specs for gen 1 motor are every 15000 miles.
intake 0.10-0.20 mm
0.004-0.012 in


exhaust are
0.20- 0.30 mm
0.008-0.012 in

 

[xc700]

how many miles are on the bike? valves normally tighten up on new motor and the valve hangs open and you burn the valve from not closing all the way. if you buy hot cam shims your not going to get right on specs, only with oem shims

 

[202mphbusa]

When I was running motor and Spray
I used to adjust my valve clearances to withing .001 I can grind my own shims
tried tighter and looser made no dynoable diffference from what I could tell

Now I use the feeler gauges as a go-nogo gauge I do go down .001 on the high end

 

[202mphbusa]

inlet is .008 max
not .012
I go .004-.007
.008 to .011 go no go if the .004 or .008 drag and do not FLY cams come out

 

[rubbersidedown]

This is one area where Suzuki usually has it right,not like when they build a transmission. Most owners usually report no change needed at first service. Kiwi is smart,not much need to reed any further IMHO.
Rubb.

 

[clean]

how many miles are on the bike? valves normally tighten up on new motor and the valve hangs open and you burn the valve from not closing all the way. if you buy hot cam shims your not going to get right on specs, only with oem shims

2008 - 23k miles. just exhaust a bit tight. will use +.10 and +.15 shims to get to the looser end of the spec.

why would hot cams shims be any different ....I thought both hot cams and OEM come in .05mm increments?

 

[c10]

2008 - 23k miles. just exhaust a bit tight. will use +.10 and +.15 shims to get to the looser end of the spec.

why would hot cams shims be any different ....I thought both hot cams and OEM come in .05mm increments?

OEM shims can be ordered in smaller increments . Tech tip the old school knife sharping tri stone with course . medium , and fine in a 2 inch by 8 inch long can be used to make a shim by hand true flat for 2.75 mm to 2.73 mm . Each shim by hand takes about 8 to 15 minutes using honing oil . This prevents shim from getting hot . Make sure your doing only one side . Use a marker to mark the other side in case you drop the shim .

 

[Berlin Germany]

@c10

i "learned" to put in the shims with their number upside to the cup tappet - that way the shim´s inscription would not be erased by the valves end.

your trick with the knife sharpener is pretty nice - thx for that - i will try too.

@clean
1. - metric feeler in steps of 1/100 using is the biggest precision you can get
2. - yes, the increment of suzuki shims is usually 0.05 mm, x.x 0 / x.x 5
but suzuki also sells shims with x.x2 / x.x8 what you can read on these "special" shims
3. - even those specials again can have tolerances of 1-2/100 mm (0.01-0.02) ==> x.x2 or x.x4 or x.x9 possibly can be found.

so when i join my dealer for new shims i there use allways my micrometer (precision = 1/100 mm)
and by that the possibly existing tolerance of my micrometer is the same when taking the thickness of the shims at my dealer
and so my basic meassuring is still correct.
(my suzuki dealer changes old shims to those i need for only 3.00€ per shim - new they cost around 10-12€ p.p.)

and - if i remember correctly the "hot cam" shims are at the size what is inscripted in steps of only 5/100.

and - have a look at this page - this german dealer for OEM stuff offers shims in x.x25 and x.x75 "steps"
( i havn´t bought those yet - so i can say nothing to their precision)

 

[clean]

@Berlin Germany

Thanks for the shim info. my bike had some x.x8 shims installed from the factory which came in handy to re-use on other valves.

Unfortunately all of my measuring equipment is in inches. with a combination of the hot cams shims and re-using one of the suzuki shims I was able to get all the clearances within a few tenths of each other (on paper) with the exception of one which I had to stone hone down .0015 which worked like a charm thanks to @c10 's tip. I used a double sided Sunnen brand stone with oil - worked great.

they are all @ .010 or just over now ( again on paper) .....will install and hope all remains the same.

 

[clean]

Thanks everybody for the help. all the clearances after adjustment were spot on @ .010 as planned BUT, made a bit of a rookie mistake.

The chain must have moved a tooth on the crank when I had the exhaust cam out. When the arrow on the exhaust cam is level with the head the line on the crank is forward in the clockwise direction about 1/4". still 15 chain pins between arrows on cam sprockets.

is there anyway to get it to move a tooth on the crank without taking the cam out again? or get it to jump a tooth back on both cams while staying on the crank if you know what I mean? @c10

 

[c10]

Thanks everybody for the help. all the clearances after adjustment were spot on @ .010 as planned BUT, made a bit of a rookie mistake.

The chain must have moved a tooth on the crank when I had the exhaust cam out. When the arrow on the exhaust cam is level with the head the line on the crank is forward in the clockwise direction about 1/4". still 15 chain pins between arrows on cam sprockets.

is there anyway to get it to move a tooth on the crank without taking the cam out again? or get it to jump a tooth back on both cams while staying on the crank if you know what I mean? @c10

My best advice is pull cams , and re time motor per manual . Reinstall cams , and check timing over several rotation to TDC , and BDC . Not worth the bent valve or cracked piston FYI on a ZRX one tooth off runs like poo . Ask me how I know lol

 

[Kevin Jones]

When you put the cam chain tensioner back in, it will take up significant tension into the chain. If there are still 15 teeth between, its possible the crank rotated without the tensioner in there and if I recall, it does that about a 1/4" when you pull the tensioner out on a stock motor. I just cant say whether when it did that if it pulled the chain over the cam or not, not without looking at it. If the crank turned and the cam was still bolted in, yes, the chain moved, you wont get that cam to move those valve springs before the chain decides to walk a tooth or two. You can bolt it back together and 1 tooth off is not going to make valves contact on a stock motor. Just slowly rotate the engine over by the crank bolt clockwise and if you feel ANYTHING odd, stop. Pull it apart and start over. Did you replace the chain? If the chain is stretched, its impossible to get the arrows to line up perfectly and even when you think the lines of the chain cover and crank are aligned, its not typically truly TDC anyway, but its pretty close. Sometimes its right on. Regardless, I have done stock rebuilds with new chains that I simply couldn't get the arrows to line up perfectly (in a OCD way) and they ran like scalded dogs for a stock motor.

 

[mjl3truck]

If you want to go crazy you can get shims for a CR450 in "half" sizes. They are OEM through Honda so they ain't cheap

 

[clean]

When you put the cam chain tensioner back in, it will take up significant tension into the chain. If there are still 15 teeth between, its possible the crank rotated without the tensioner in there and if I recall, it does that about a 1/4" when you pull the tensioner out on a stock motor. I just cant say whether when it did that if it pulled the chain over the cam or not, not without looking at it. If the crank turned and the cam was still bolted in, yes, the chain moved, you wont get that cam to move those valve springs before the chain decides to walk a tooth or two. You can bolt it back together and 1 tooth off is not going to make valves contact on a stock motor. Just slowly rotate the engine over by the crank bolt clockwise and if you feel ANYTHING odd, stop. Pull it apart and start over. Did you replace the chain? If the chain is stretched, its impossible to get the arrows to line up perfectly and even when you think the lines of the chain cover and crank are aligned, its not typically truly TDC anyway, but its pretty close. Sometimes its right on. Regardless, I have done stock rebuilds with new chains that I simply couldn't get the arrows to line up perfectly (in a OCD way) and they ran like scalded dogs for a stock motor.

Thanks for pointing out that a older chain may not get perfect alignment. I think my OCD is kicking in a bit here too.

I also put a dial indicator on the top of the piston. the timing marks on the crank and cover are basically right on the money, but its just that when the crank marks are aligned the arrow on the exhaust cam is Slightly up a little more then perfectly in line with the head surface....this could definitely be a combo of a used chain and my ocd, but to be sure im going to go through the motions in the service manual.

Good to know that I wont be smashing valves even if im out a tooth

 

[Kiwi Rider]

Good to know that I wont be smashing valves even if im out a tooth

Can I just say that IF, and I mean IF you are out by one tooth, it will be extremely obvious by looking carefully at the marks on the crank, then the marks on the cam sprockets and the proximitry to the edge of the cyl head .
I doubt very much you would miss this, and put it together and start the engine.
So, I think you are safe here.
Just be sure you have the pins counted too.
As already said, rotate the engine slowly and carefully AFTER you have installed and set the tensioner, then check to confirm all marks are still lined up, then you're good to button it all up and run it . . . hmmmmmmmm . . . Busa running . . . hmmmm

 

[clean]

@Kiwi Rider
Haha, thank you. That's a bit comforting. I'll try to get some strait on pics of the timing Mark's and post them.

Yes busa running...mmmm...busa running

 

[Kevin Jones]

Just note that the absolute worst mistake you can make (maybe) is to get a long day going with things going wrong, get distracted, have to come back to the job 5x, awake for way too long and bolt the cams down in a hurry without lining up the crank. You will bend the valves and not even know it torqueing down the caps. And absolutely use the recommended ft lbs on those bolts, do not just tighten them down. If you overly tighten them, you will distort the cam covers and possibly burn one of the bearing surfaces and/or strip the threads in the head. Its actually not a bad idea to take a good look at those surfaces now and make sure neither they nor the cams look like it got hot or just distorted or any surface that just looks a lot different than any others. AND AND make sure you get those bearings in there lined up right in the c clips or you may hear a heart wrenching (crack) sound when torqueing the caps down and that is the sound of one of those bearings cracking. They are so fragile.