Valve clearance check (timing of) in the real world.

[2and3cylinders]

Greater than or equal to .028 is OK but in another 12K they could drop.

For the intakes closer to .018 is better...but existing consistency is encouraging 

 

 

[dazzler24]

1 hour ago, 2and3cylinders said:

Greater than or equal to .028 is OK but in another 12K they could drop.

For the intakes closer to .018 is better...but existing consistency is encouraging 

 

Thanks Bret, I'm sure you've added a zero on those but get what you're saying.

Question - the 4 that are 0.28, do I leave their shims alone so that they remain evenly gapped per cylinder or make them uneven by moving some shims around? i.e. I could make cylinder 1 - 0.28 and 0.29 and cyl 2 - 0.3 and 0.28 by moving the shims from cylinder 3 across as per the proposal below.

Can you confirm my proposal for shim rearrangements and additions for the exhaust please.

Keeping in mind I have a Hot Cams kit that is in 0.05 increments only.

Left to right my existing shims and gaps are:-

      1                 2                   3

L      R           L     R            L     R

190; 191       191; 189        190;189

0.28;0.28     0.28;0.28      0.26;0.26

 

Proposal is to use 3L (190) in 1R, 3R (189) in 2L.   2 x new 185s in 3L&R. The rest stay as they are.

This (on paper) would put them so:-

      1                   2                  3

L        R          L     R            L      R

190; 190       189; 189       185; 185

0.28;0.29     0.3;0.28        0.31;0.3

TIA

EDIT - OR for more consitency: -

      1                   2                  3

L        R          L     R            L      R

189; 190       191; 189       185; 185

0.29;0.29     0.28;0.28        0.31;0.3

[peteinpa]

Wow, at 12.5k miles you're still in spec. Did not expect that.

In spec is in spec.  I'd leave it alone but check again at 20k miles.

I'm posting this again. it's the emissions sticker for my 15 FJ-09. It's located under the rear fender, you lay your phone on the rear tire to take a pic.

Note the EX spec.: .24-.30mm NOT the same as the manual. The sticker makes MORE sense, the range is then larger, still not the range of the intakes.

Edited March 29, 2022 by peteinpa

[2and3cylinders]

I meant previously that .28 is close enough for the girls we go out with; i.e.,don't mess with a good thing.  I'd  adjust ex #3 & all the intakes now.  If you want to reset ex 1 & 2 as well, go for it.  Regardless, certainly recheck lash after reinstallation of the cams and CCT and after cranking it over a few times.

The closer the exhaust and intake are to top spec the better IMO with a CP3 . Now that you'll be a pro, recheck in 12K or so when you replace the plugs again.

[skipperT]

Daz-

here’s the thing: what mindset of an owner are you? Another words, will you be keeping the bike long term? Can you take rides on your bike and not worry about the exhaust valve lash getting tighter before another 20 km go by?

because quite honestly, you can button it back up and check it in another 15-20k km. Everything is in spec. 

however, if you like to tinker and you want the peace of mind of knowing you (tried to or) set the exhaust valve lash on the loose side of spec, then pull the ex cam and loosen them slightly.

If you choose that route, you have to accept the possibility (here’s an example) that Yamaha may have stuck a 1.86mm shim in one (or all) of those positions, and you’ve got a 1.85 in hand or a 1.80 in hand. Meaning, the 1.85 loosens it slightly, which may not be detectable when measured with a feeler gauge - but the 1.80 puts you at .32-.33mm of clearance which is technically 1 click looser than spec. So you really need a 1.82 or 1.83 in this example and may not have a shim that will work  

It all depends on what your engine has in there currently. Worst case scenario, make sure you write down what shim your engine currently has in which spot, so you can always go back together exactly as it is… knowing that you tried and will get it in the next go-round. 

(wrote this last night but it didn’t post…sorry!)

-Skip

[skipperT]

On 3/11/2022 at 1:58 PM, dazzler24 said:

 

When I wrote that (about the Valve cover) I may have confused this engine with another…

disregard that statement. You can rotate the engine over without the valve cover as long as the tensioner is installed correctly and is tensioning the cam chain. 
 

If not, or if the tension is loose - it will skip over the sprockets. 
-S

[dazzler24]

13 hours ago, 2and3cylinders said:

I meant previously that .28 is close enough for the girls we go out with; i.e.,don't mess with a good thing.  I'd  adjust ex #3 & all the intakes now.  If you want to reset ex 1 & 2 as well, go for it.  Regardless, certainly recheck lash after reinstallation of the cams and CCT and after cranking it over a few times.

The closer the exhaust and intake are to top spec the better IMO with a CP3 . Now that you'll be a pro, recheck in 12K or so when you replace the plugs again.

Thanks Bret.  I'm going to try for closer to maximum gaps.

 

10 hours ago, skipperT said:

Daz-

here’s the thing: what mindset of an owner are you? Another words, will you be keeping the bike long term? Can you take rides on your bike and not worry about the exhaust valve lash getting tighter before another 20 km go by?

because quite honestly, you can button it back up and check it in another 15-20k km. Everything is in spec. 

however, if you like to tinker and you want the peace of mind of knowing you (tried to or) set the exhaust valve lash on the loose side of spec, then pull the ex cam and loosen them slightly.

If you choose that route, you have to accept the possibility (here’s an example) that Yamaha may have stuck a 1.86mm shim in one (or all) of those positions, and you’ve got a 1.85 in hand or a 1.80 in hand. Meaning, the 1.85 loosens it slightly, which may not be detectable when measured with a feeler gauge - but the 1.80 puts you at .32-.33mm of clearance which is technically 1 click looser than spec. So you really need a 1.82 or 1.83 in this example and may not have a shim that will work  

It all depends on what your engine has in there currently. Worst case scenario, make sure you write down what shim your engine currently has in which spot, so you can always go back together exactly as it is… knowing that you tried and will get it in the next go-round. 

(wrote this last night but it didn’t post…sorry!)

-Skip

Thanks for the info skip and for right or wrong, I am a tinkerer so will try to get things as close as possible to max gaps.

I noticed in another post by you (somewhere) that you mentioned that you had a valve that measured 0.32 but was happy to leave it that way.  Do you still prescribe to that given your 'caution' above re putting a valve outside of spec on the looser side?

EDIT UPDATE: -  I've given myself an uppercut and realised that these figures are really fine "for the girls we go out with" according to 2and3cyclinders.

So I'll button her up, change the plugs, sync the throttle bodies and do some minor maintenance and call doing the valve clearance quits for another 20K kms.

Thanks to all who commented/contributed. 👍

[skipperT]

15 hours ago, dazzler24 said:

Thanks Bret.  I'm going to try for closer to maximum gaps.

 

Thanks for the info skip and for right or wrong, I am a tinkerer so will try to get things as close as possible to max gaps.

I noticed in another post by you (somewhere) that you mentioned that you had a valve that measured 0.32 but was happy to leave it that way.  Do you still prescribe to that given your 'caution' above re putting a valve outside of spec on the looser side?

EDIT UPDATE: -  I've given myself an uppercut and realised that these figures are really fine "for the girls we go out with" according to 2and3cyclinders.

So I'll button her up, change the plugs, sync the throttle bodies and do some minor maintenance and call doing the valve clearance quits for another 20K kms.

Thanks to all who commented/contributed. 👍

I would remeasure the clearances after you install the new shims, @dazzler24  you didn’t write that in your reply, but I hope you did that. 
 

as you mentioned, we’re splitting hairs at this point. All of you math makes sense above, but I worry that the adjustments to the intake shims you wrote down may put you too loose on the intake side. There may/may not be a downside to that, unknown by me, if they wind up around .22-.25mm. Just a heads up. 
 

-S

[peteinpa]

In spec. is in spec. Just ride it.

Keep in mind that loose valves decrease lift and duration. effectively changing power characteristics. On a powerful engine like this you might not notice.

I noticed a big change in power on a 250 when I first adjusted normally. Power dropped. I then set for minimum gap (easy to do with screw and lock nut) and got the power back.

[dazzler24]

13 hours ago, skipperT said:

I would remeasure the clearances after you install the new shims, @dazzler24  you didn’t write that in your reply, but I hope you did that. 
 

as you mentioned, we’re splitting hairs at this point. All of you math makes sense above, but I worry that the adjustments to the intake shims you wrote down may put you too loose on the intake side. There may/may not be a downside to that, unknown by me, if they wind up around .22-.25mm. Just a heads up. 
 

-S

Hi @skipperT, at the bottom of my previous post I woke up to myself and decided to leave well enough alone.

I had removed all of the shims prior to this and they all went back into their original locations.

I then followed the procedure - reinstall CCT, cut cable ties, check timing punch marks align and then turn the motor over a few times by hand and then rechecked.

I was very slow and deliberate with my feeler gauges this time and believe that while the exhausts were the 'same' if not very slighty tight at 0.28, the intakes 'improved' slightly so that was reassuring good news in itself.  See final measurements below. (Ignore arrows and the red numbers as that was what I had planned to achieve)

11 hours ago, peteinpa said:

In spec. is in spec. Just ride it.

Keep in mind that loose valves decrease lift and duration. effectively changing power characteristics. On a powerful engine like this you might not notice.

I noticed a big change in power on a 250 when I first adjusted normally. Power dropped. I then set for minimum gap (easy to do with screw and lock nut) and got the power back.

Yes, you're right and that's what I've done.  Buttoning it back up and I'll forget about them for another 20K kms.

Interesting what you say about the power changes in relation to valve lash as I spoke to the local Yamaha mechanic yesterday (when I was still delusional and trying to get those odd shims) and he was relating his experiences with flat track bikes he used to ride and tune.  He said he would adjust his valves to do just what you said to squeeze maximum power out of his machines to be competitive on the track.

I've learned somthing new.

Thanks for commenting.

[2and3cylinders]

Yes, for max power but when racing you're also checking them between meets.

For street use it depends how close they are.  I had them tighten up in less than 15k miles after checking them at 35k...

Then there's the philosophy of "as long as you're in there you might as well make it right", as only right as right...

[dazzler24]

4 hours ago, 2and3cylinders said:

Yes, for max power but when racing you're also checking them between meets.

For street use it depends how close they are.

That's almost word for word of what the mechanic said!  You're all over it 2and 3. 🙂

On another note, I found that when doing my throttle body sync the white screw no longer cut it as master so now I've got a new 'master'.  Was 3 and now 2.  I noticed at the last sync it was very marginal but now enough of a change in the vacuum to warrant the switch.

[koth442]

6 hours ago, dazzler24 said:

That's almost word for word of what the mechanic said!  You're all over it 2and 3. 🙂

On another note, I found that when doing my throttle body sync the white screw no longer cut it as master so now I've got a new 'master'.  Was 3 and now 2.  I noticed at the last sync it was very marginal but now enough of a change in the vacuum to warrant the switch.

Man, your 4th cylinder is really far off!!

Sorry, I couldn't help myself

[2and3cylinders]

Close enough for the girls...

Daz, did you check sync at various elevated RPM?

I try to average the readings at idle, 3500, 5500 and 8500, then tweak the final setting at idle.  The much wider spacing of the cm hg indexing on my ancient Mercury vacuum gauge makes balancing much easier and also more accurate.

For more than 2 cylinders changing the master really isn't an issue.  Mine came with number 2 as the leader.  On many old real carburated engines the sync method was only possible within the mechanical linkage or throttle cables.  For example, on my RD400, threaded inspection plugs in the carb body adjacent the slides which had a small dimple drilled precisely at the same height in the side of each permits matching the slide heights.  Talk about crude but close enough for the girls, government work, hand grenades etc

Years ago before it became unobtainable without a license, I bought inexpensively a small quantity of Mercury to replenish my mamometer if needed due to accidental loss.  Have you ever tried to corral and recapture loose beads of Mercury, let alone without poisoning yourself?

[dazzler24]

14 hours ago, 2and3cylinders said:

Close enough for the girls...

Daz, did you check sync at various elevated RPM?

I try to average the readings at idle, 3500, 5500 and 8500, then tweak the final setting at idle.  The much wider spacing of the cm hg indexing on my ancient Mercury vacuum gauge makes balancing much easier and also more accurate.

For more than 2 cylinders changing the master really isn't an issue.  Mine came with number 2 as the leader.  On many old real carburated engines the sync method was only possible within the mechanical linkage or throttle cables.  For example, on my RD400, threaded inspection plugs in the carb body adjacent the slides which had a small dimple drilled precisely at the same height in the side of each permits matching the slide heights.  Talk about crude but close enough for the girls, government work, hand grenades etc

Years ago before it became unobtainable without a license, I bought inexpensively a small quantity of Mercury to replenish my mamometer if needed due to accidental loss.  Have you ever tried to corral and recapture loose beads of Mercury, let alone without poisoning yourself?

Didn't check at higher revs, just followed the service manual on this occassion.  Only revved the engine between tweaks, again, as per the manual.

And yes, I have had the pleasure and wonder of chasing Mercury around a plate as a child - unaware of the health implications in my ignorance.  Good times!