Done at 65000 miles?

[snyper316]

Nope the weep hole in the water pump... I put the new impeller in and I'm betting I will have to replace the seal and bearing.

 

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[cowpuc]

I just open mine and type valves! lol tell you older ones still believe in books. [emoji87]

 

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I like the greasy fingerprint marks inside my shop manuals from endless adventures of days past Snype,, kind of like looking a family photo album for these tired old eyes,, somehow the telling of the story of great times between a geezer and his faithful iron horse... Nuts huh..

[cowpuc]

Well when i did my valve job on the 99 i remember they were all in spec except for one or two and they were both so close to being in spec i wondered if i should have even changed them. I've got the manual and they've got that nifty little table to tell you which valve to switch it too.

 

Thinkin ya meant what "shim" to switch to to either open or close the gap between the shim and the cam lobe face?? Still gotta be some kind of a tolerance spec in either thousandths or millimeters there I would think. This would be measured with a feeler gauge stuck between the lowest point of the cam surface (opposite of the lobe face) and the shim face.. I probably am not explaining what I am trying to say here (not unusual),, hold on,, I am gonna go see if I can find my shop manual,, now I am curious ,,,

[cowpuc]

Nope the weep hole in the water pump... I put the new impeller in and I'm betting I will have to replace the seal and bearing.

 

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So did you just spin on a new impeller and not remove the entire water pump assembly and rebuild the whole unit the first time Snype? That is kind of a no no unless your really really really fortunate cause that ceramic seal dont take much abuse (like knocking an impellar loose to spin on another one)..

[snyper316]

So did you just spin on a new impeller and not remove the entire water pump assembly and rebuild the whole unit the first time Snype? That is kind of a no no unless your really really really fortunate cause that ceramic seal dont take much abuse (like knocking an impellar loose to spin on another one)..

Yeah I kinda umm didn't know... So anyways gonna be ordering that stuff tomorrow.

 

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[Chaharly]

Thinkin ya meant what "shim" to switch to to either open or close the gap between the shim and the cam lobe face?? Still gotta be some kind of a tolerance spec in either thousandths or millimeters there I would think. This would be measured with a feeler gauge stuck between the lowest point of the cam surface (opposite of the lobe face) and the shim face.. I probably am not explaining what I am trying to say here (not unusual),, hold on,, I am gonna go see if I can find my shop manual,, now I am curious ,,,

 

I guess what I'm asking is if, for example the minimum clearance is 5mm and i find one that's at 4mm. Should i bite the bullet and get a shim kit and do both sides? Or should i look for a more extreme difference? Remember that's just an example. I'm at work right now or I'd look at what the clearance is

[cowpuc]

I really have never done one Cha so I have no idea what Yamaha spec is on em but, having done numerous other scoots, I would say anything less than 2 thousandths on the intakes and 3,, maybe 4 thou on the exhausts (that would be .002, .003, .004) and I would call them dangerously tight. IMHO, valves/seats usually wear tight - not loose and it's the runnin tight that leaves the valve open a tad and poof,, burned valve. That said,, probably not be a bad idea to check Yam spec to see how close of guess that is,,, you got a Shop Manual? I can look it up real quick if you need me to, just a short walk downstairs - open a file cabinet - open the book to check with Mom Yam

 

You are welcome on the offer!!

 

Well when i did my valve job on the 99 i remember they were all in spec except for one or two and they were both so close to being in spec i wondered if i should have even changed them. I've got the manual and they've got that nifty little table to tell you which valve to switch it too.

 

Yeah I was wayyy off,, spec is 4 intake and 6 exhaust tightest gap tolerance between the shim and cam on the 1st Gen..

[cowpuc]

I guess what I'm asking is if, for example the minimum clearance is 5mm and i find one that's at 4mm. Should i bite the bullet and get a shim kit and do both sides? Or should i look for a more extreme difference? Remember that's just an example. I'm at work right now or I'd look at what the clearance is

 

Got cha ya Cha,, on the same 2 track brother.. Seeing this spec as shown in the manual,, if I rolled the piston to TDC on the compression stroke on the jug I was working on and could manage to get a 3 thousandth feeler in between the cam and the shim on the intake and a 5 on the exhaust and I had over 50k on the scoot I would know that my bike is getting at least 1 thou of wear per 50k miles. If my goal was to end up at 200k with no burnt valves from valves going tight, see if you can follow my ill fated logic here = 3 thou x 50k = 150k, 150k + 50k (my test start point) = 200k = TAHHH DAHHH

 

Now for another Puc Point (like all Puc Points = totally 100% still in theory state and up for debate), one of the things I have learned thru time in dealing with other bikes valve trains is that generally speaking, its the first tens of thousands of miles on a new engine that shows the highest percentage of lash wear (all wear actually,, in the old days us back yard mechanics called this period of time "break in") and as the engine increases in mileage after being "broke in", the tolerance stacking actually stabilizes significantly.. Put in another way without my totally destroying any form of Algebraic decency that may have survived what I just tried to explain, I would buy .003 intake and .005 exhaust as absolute minimums if my scoot had +50000 miles on it, had never had the valves adjusted priorly and my goal was 200000 miles and the factory manual specs read like this (from my Shop Manual):

[Flyinfool]

If you are in far enough to stick a feeler gauge in there to measure the clearance, why on earth would you not take the extra 5 minutes and $5 to change to an in tolerance shim and know for certain that you are good for a long long time??

 

There are plenty of places to get shims from ranging from free to $10.

 

By far the getting to the valves is the worst part of the job.

 

I had to replace a leaky valve cover gasket so I adjusted all of the valves to the high limit of the tolerance. I figured that would mean I would never have to check them again in my riding time that I had left, unfortunately, I was right.

Two of my valves were at less than .001, not touching, I could still spin them in the pocket, but my .001 feeler did not fit, Those would have been burnt valves in the very near future had I not checked and changed as required. This was at 55K miles. Do you feel lucky? There was even one valve that was OVER by 3 thou. The factory must have set that one real loose or popped the shims in the wrong spots because switching the shims from the loose one to the tight one almost brought them both back in spec.

Edited March 18, 2019 by Flyinfool
fat finers

[RDawson]

Intake.004-.006

Exhaust .006-.008

These are the tolerances in the book. Definitely want to set to the high side for long range. I bought the gaskets from Skydoc and got to use his shim kit. I recommend doing similar, by having a variety of shims you can change each one as you get to it instead of checking and recording all 16 and then going back thru to switch around. I needed two shims not in his kit so had to wait a few days to finish but it but it went much easier than I anticipated. I printed the instructions from the read only library, got Skydoc's kit, and another member sent me the shims I needed, so with the help of VR I got the job done. With 43-44k miles I had several on the low side of tolerance with none being critical. I took the time to push them all to nearly full gap so should be good for a long time. I'm with the others if you're almost to the valves invest a little more time if for no more than peace of mind.

[Chaharly]

Got cha ya Cha,, on the same 2 track brother.. Seeing this spec as shown in the manual,, if I rolled the piston to TDC on the compression stroke on the jug I was working on and could manage to get a 3 thousandth feeler in between the cam and the shim on the intake and a 5 on the exhaust and I had over 50k on the scoot I would know that my bike is getting at least 1 thou of wear per 50k miles. If my goal was to end up at 200k with no burnt valves from valves going tight, see if you can follow my ill fated logic here = 3 thou x 50k = 150k, 150k + 50k (my test start point) = 200k = TAHHH DAHHH

 

Now for another Puc Point (like all Puc Points = totally 100% still in theory state and up for debate), one of the things I have learned thru time in dealing with other bikes valve trains is that generally speaking, its the first tens of thousands of miles on a new engine that shows the highest percentage of lash wear (all wear actually,, in the old days us back yard mechanics called this period of time "break in") and as the engine increases in mileage after being "broke in", the tolerance stacking actually stabilizes significantly.. Put in another way without my totally destroying any form of Algebraic decency that may have survived what I just tried to explain, I would buy .003 intake and .005 exhaust as absolute minimums if my scoot had +50000 miles on it, had never had the valves adjusted priorly and my goal was 200000 miles and the factory manual specs read like this (from my Shop Manual):

https://www.venturerider.org/forum/attachment.php?attachmentid=115804https://www.venturerider.org/forum/attachment.php?attachmentid=115805

 

Lol well I suppose then, brother puc, all we can do is wait and see what I got for clearances. I'll wait until I get the new gasket before I pull the cover. If I'm a thousandth shy though I think I will wait until 100k to do a valve job on it. Another thing I've always wondered for people who like to spank that red line.... do valve springs get weaker with age? Would that effectively lower our "red line"??

[BlueSky]

do valve springs get weaker with age? Would that effectively lower our "red line"??

 

Valve springs can get weaker with miles but they seem to hold up rather well. If they get weak enough they can't close the valves quick enough at high rpm, the valves will "float" with the engine missing and not being able to rev any faster. Our old Venture engines don't have rev limiters as far as I know, so you can over rev them and probably float the valves.

[Chaharly]

I'm not the type of guy to bury it in the red anyway. I let it just kiss the red line! I've always wondered about it since some of our bikes are 36 years old!