Valve clearances question (thinking a buckets issue)

[J.M.]

EDIT: Page 2, near the bottom, longish post, are the new details.

First of all, a photo of the relevant Haynes manual page to my question. Mine's K3 onwards so 5.5b and 5.5c are relevant:
https://i.imgur.com/RUaUB.jpg?2

Essentially there are two marking on the pulse generator coil bit:
- RT
- LT
Both of them have a vertical line which should align up with the metal point on the coil.

Initially, rotating it clockwise with a 19mm spanner, I set it to RT. It sat on the line perfectly:
https://i.imgur.com/j14J0.jpg?1

However when checking the notches, they were both facing outwards, not inwards:
https://i.imgur.com/36Iil.jpg?1

So I turned it another 360 degrees, back to RT. However when turned 360 degrees so that the notches face inwards, it's impossible to get the line to line up properly as before. Instead it looks like below, which is quite far off. It's possible to hold it in the correct position with a spanner, but upon releasing the spanner it will spin back to this position:
https://i.imgur.com/ttF5f.jpg?1

The notches look like so:
https://i.imgur.com/njhdY.jpg?1

My question is... what's up with that? How come it isn't seating properly when facing inwards on RT but it is when facing outwards on RT?

The second question is... is this alright to work with? If I measure/set the valve clearances whilst it's in that position will I set it incorrectly/get the wrong readings?

Any help appreciated
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2004 R1 & 2018 XSR900

[Pete.]

Makes no difference whatsoever. All that matters is that the feeler gauge is used against the base circle of the cams.

Bit odd that the marks line up notches out but not notches in, since out is exactly one full turn from in. Unless the notches are milled off-nentre in the cam. In any case, for the purpose of setting the clearances is matters not at all.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[J.M.]

Brilliant, thanks, I'll get those checked tonight then
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2004 R1 & 2018 XSR900

[J.M.]

Okay. Clearances measured. Little confused for where to go now.

I've done all I can tonight, I don't have time to measure the shims tonight (apparently my micrometer isn't accurate enough to measure them anyway... I'll bodge something using the feeler gauges to measure them).

Clearances... "ok" range is 0.03 to 0.08.
2 clearances are okay. 1 clearance is a tiny bit out.

1 clearance was either 1.30mm or 1.31mm?! This was the right cylinder front one (front being closest to the headlamp).

Bit confused as to where to go from here. My chart for valve clearances only lists valve clearances in the range of 0.02 to 1.03... 1.30 is way off of the chart.

Would this valve clearance being so far out be the reason for the poor starting and mpg that the bike has been having?

Edit: really far out one is rhs exhaust. Found a diagram saying which each one was!
For anyone interested, I also found a calculator to calculate needed shim sizes:
https://www.stanford.edu/~sanjayd/shim_calculator_GS500.xls

Tomorrow or boxing day I'll measure the current shims so that I can head out and buy the shims that I need
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2004 R1 & 2018 XSR900

[Pete.]

That is a long way out. Probably a bent valve. Might be a sticking bucket but doubtful. See if there's any way to measure the height of the stem top and compare it against the others.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[J.M.]

[Pete.]

Yes, that would do it, measure the amount of bucket showing above the guide, if it's less than the others then you have a valve which isn't seating properly, probably from a bent head.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[J.M.]

Bugger. The head's going to be a nightmare to take off given how rusty the exhaust bolts look. I'll get some WD40 on the exhaust bolts now, just in case, and take a quick look at the buckets.
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2004 R1 & 2018 XSR900

[J.M.]

Okay, just been out again.

Full cycle on this engine is 620 degrees. First 360 degrees for rhs intake, exhaust and lhs intake. Second 360 degrees for lhs exhaust.

It seems that the valve clearance for the rhs exhaust varies per 620 degrees? One iteration may be 1.3mm, the next iteration may be 0.53mm... and so on. I gave up measuring after the second iteration but the bucket height was noticeable different on each 620 degree iteration.

What does this mean?

Edit: If it means anything... my right hand side down pipe has a dent in it from my accident in June.
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2004 R1 & 2018 XSR900

[Pete.]

720

If the valve doesn't seat fully every time you have to find out why.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[J.M.]

Yes, 720, that's what I meant! I'm going to fail my maths exam at this rate...

I'm assuming the only real way to find out why is to take the head off?

Could the exhaust value not closing properly be the reason for poor cold starting? Before I started attempting to fix it... it was popping and banging when trying to start... but running fine once started.

Anyway, I hope that the exhaust bolts on the head are nice to me
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2004 R1 & 2018 XSR900

[EazyDuz]

WD40 does little to help rusted bolts, get some penetrating oil, that stuff is a god send.
Can't help with anything else though, ive only done tappets on much more basic engines
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To shreds you say? Tss tss tss

[J.M.]

Yeah just been reading up on removing rusted bolts and everyone has been saying WD40 is completely useless.

I don't have anything else though and everywhere will be closed on Christmas. I need the bike back on the road by the 6th. I'll have to play around with a blow torch to heat the bolt head up without heading the thread up too much and hope that loosens it up enough!
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2004 R1 & 2018 XSR900

[Blau Zedong]

[J.M.]

I know

Well actually... if I put it back together as it is... it works... just poorly.
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2004 R1 & 2018 XSR900

[P.addy]

I'll service the Vara for you...

[orac]

sounds like you have a screwed valve.

before you go ahead and use the other head, you should leak test it - turn the head upside down and use something like parrafin ine the pistone wells, then leave it. donwt use something that will evaporate as this will make you think that the valve are leaking - dont use water for obvous reason.

mind you dont loose the shim when you upturn the head. and yes valves not seating will cause mega starting issues. a compression test would have shown valve issue.

i got me one of these
https://www.machinemart.co.uk/shop/product/details/clarke-cht693-8-piece-compression-tester-kit?da=1&TC=SRC-compression+tester
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Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[J.M.]

[orac]

have you ever done a valve replacemnt? if not, i would check the other head for squareness, leak test it and be done.

if you replace the valve, you should ideally while there do all the seal and re-seat all of them. another problem is you should in theory, not just do the valve stem seal but the valve guide to (differnt wear on the stem and guides), at least for that one valve.

do you have th correct size valve spring compressor too.

how ever today maybe your lucky day - specaily if you just want to swap the heads. i have a GS500 head gasket here, brand spanking new, still in the packet. Part numer: 11141-01D10

i also have valve seals
09289-07002 x4
11143-06b00 x4

you can have the haed gasket for £20 plus what ever delivery you want. i picked them up for doing my leaking stems on mine, then a good engine with alot less miles came up for less than £50
____________________
Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[J.M.]

[orac]

the 4 o-rings and 4 seals are £5.84 each and £5.74 each repectivly on robinsons (head gaskeet is £23.55 on there), with my current monetary situation i cant give away more than40 quids worth of gear.

i would say £30 quid for the oil seals and o-rings.

not when the post offive opens again, but i will get it packaged and use the royal mail site to get a price, i would think the recorded next delivery, maybe before 9am ig you want to pay the extra
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Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[Pete.]

[J.M.]

Orac, payment sent

Pete, I haven't taken a proper look at the tools yet, just a quick glance. He seems to have two large C clamps which look extremely similar to the ones I saw in a video of someone working on the GS500 engine.

Here's the one they used in the video to compress the valve springs:
https://cdn.bikechatforums.com/files/valve_spring_compressor_001.png

I'll fire the old laptop up to find the rebuild video I downloaded.
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2004 R1 & 2018 XSR900

[Pete.]

Yeah that one has the extension on the bottom for reaching inside the well of the head. It's fixed by the bolt that the guy's left thumb is pointed at.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[J.M.]

Oh yes, I see it now
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2004 R1 & 2018 XSR900