Oil pump shims

[iainw]

Does anyone know where I can get these from or have the Yamaha part number? Mine has none in and the gap is closed.

It's an '81 350LC whith a 4L1 mark on the pump.

[Norbo]

This will be the very small one at the botomif the pump spline yes .

[arrow]

I make my own. Any correct size washers will do. Just rub them down on a sheet of 600 wet/dry to get the thickness you require.
Just done a pump for a club member, the gap was minus 0.13mm! Ie a had to make a 0.39mm shim to get a gap of 0.25mm if that makes sense.

[Tone]

If you mean the shims to alter the minimum stroke the parts numbers are
137-13137-00-03 which is .03mm or about 1 thou thick
137-13137-00-05 which is .05mm or about 2 thou thick
137-13137-00-10 which is .1mm or about 4 thou thick
You should be able to get these from most big Yam dealers
Tony

[arrow]

Just to be clear, the first 2 are 0.3mm and 0.5mm thick. Can't comment on the last one, never seen them.

[iainw]

They're the ones though I couldn't find any in the LC shop.

The Haynes manual says the gap should be 0.15mm, mines fully closed and there's no shims in there. I've just tried a small washer and gapped it at 0.2mm so here goes with the wet and dry! Thanks for the tip Arrow.

[arrow]

Leave it at 0.2 matey. No problem.

[Tone]

I've just measured the ones I've got with my digital vernier and they all measure as my reply i.e .03mm , .05mm and .1mm.
If they were .3mm and .5mm they would be 12 thou and 20 thou thick !! If you multiply mm by 4 you get the equivalant in thou i.e spark plug gap of 0.7mm = 28 thou.
iainw, are you making sure the plunger is right out to it's limit before measuring. I usually watch the plunger with the bike ticking over and hit the kill switch when its right out and check it several times to make sure its out to its limit.
Tone

[iainw]

Dec 7, 2011 20:23:51 GMT 1 Tone said:

I've just measured the ones I've got with my digital vernier and they all measure as my reply i.e .03mm , .05mm and .1mm.
If they were .3mm and .5mm they would be 12 thou and 20 thou thick !! If you multiply mm by 4 you get the equivalant in thou i.e spark plug gap of 0.7mm = 28 thou.
iainw, are you making sure the plunger is right out to it's limit before measuring. I usually watch the plunger with the bike ticking over and hit the kill switch when its right out and check it several times to make sure its out to its limit.
Tone

The Haynes says they are available in 0.03 and 0.05mm.

Pump's off the bike. I've got it in my hand and I'm turning the gear with my pinky in the hole. It runs with no gap, but when I put an ordinary washer in I get the gap to 0.2mm at its widest.

[arrow]

The motor will be far better off left on the 0.2mm gap.
My haynes manual states 0.3 and 0.5 for the shims, as does the Yamaha parts book.

[arrow]

Also check the engine number for the correct gap. Only engine numbers prior to 4LO100101 have the smaller spec. gap. HTH.

[arrow]

See pic.

Attachments:

[oldelsieboy]

Dec 7, 2011 21:11:33 GMT 1 arrow said:

Also check the engine number for the correct gap. Only engine numbers prior to 4LO100101 have the smaller spec. gap. HTH.

Surely thats only relevant if the bike is completly standard as it left the factory, original early barrels, carbs, oil pump etc.

OEB

[iainw]

That's right, mines an '81 engine No 4L0-1014xx, so gap is reduced to 0.15mm.

I can now get it to 0.2mm, you reckon that's near enough and OK?

[arrow]

Sure, but how would you determine the correct gap due to any modyfications ?

[arrow]

Dec 7, 2011 21:32:03 GMT 1 iainw said:

That's right, mines an '81 engine No 4L0-1014xx, so gap is reduced to 0.15mm.

I can now get it to 0.2mm, you reckon that's near enough and OK?

You should be on the later (larger) gap then.

[Tone]

On the very first LCs the standard minimum stroke was 0.15 - 0.2mm or 6 - 8 thou but Yamaha sent out a bulletin to its dealers to reduce this down to 0.1 - 0.15mm 0r 4 - 6 thou and to make a new full throttle mark on the pulley 4mm down from the original as some of the bikes had an over oiling issue and were fouling plugs.

[iainw]

Dec 7, 2011 21:34:20 GMT 1 arrow said:

Dec 7, 2011 21:32:03 GMT 1 iainw said:

That's right, mines an '81 engine No 4L0-1014xx, so gap is reduced to 0.15mm.

I can now get it to 0.2mm, you reckon that's near enough and OK?

You should be on the later (larger) gap then.

One of us is misunderstanding the book.
"...gap should be 0.20-0.25mm on unmodified 1980 models. In the case of the modified 1980 machines and all 1981 versions, engine numbers 4L1 100101 (250cc) or 4L0 100101 (350cc) onwards the setting is reduced to 0.15mm."

The later gap is smaller, not larger.

[arrow]

Hang on a mo, I'll get a decent pic from the book.

[arrow]

Here;

Attachments:

[iainw]

Thanks for all the replies chaps! You've been very helpful, lots of good advice from everyone.

I'm going to take that washer down until the gap is 0.15mm, wot it says in the book.

Cheers,
Iain

[Tone]

Just had a look in my Genuine Yamaha workshop manual and your right as you say the original ones were set to 0.20-0.25mm or 8 to 10 thou.

[arrow]

Later modded to 0.15 then modded again later to the standard 0.2~0.25.

[Tone]

Didn't think they went back up to 0.2 - 0.25mm. As iainw says and the Genuine Yamaha data book I have says engine number 4L1/4L0-100101 and on the pump minimum stroke is set to 0.1-0.15mm (4 to 6 thou) as standard.

[arrow]

Ok thanks for that can we agree to differ ? And can I give you some figures on the air cooled bikes, I suspect the lc's are much the same.
The aircooled 250 pump kicks out about 80:1 at tickover revs. This becomes about 20:1 at full bore. Now some of the guy's run there bikes on premix 30:1 or 25:1 in some cases and the engine loves it, so why run on 80:1 ? It was all to do with emissions at the time I gap both my pumps big, the aircooled is on about 0.4mm this will give around 45~50:1 at tickover far better IMO. This also gives more oil at partial throttle settings. Full speed oiling is unaffected of course. The engine loves it and does not have excessive smoke. The modern oils take care of this latter fact very well.
Moral of the story; chuck as much oil through the motor as you can get away with. If the engine is in good nick it will not have a lot of smoke. It will last longer and run better. We could not do this years ago with the crap oils, for obvious reasons.

[nikfubar]

Dec 7, 2011 18:07:44 GMT 1 arrow said:

Just to be clear, the first 2 are 0.3mm and 0.5mm thick. Can't comment on the last one, never seen them.

Think you will find Tone was correct 0.03 NLA 0.05 & 0.1mm
I tried to get the 0.03mm ones to correct my setting & they kept getting 0.003, subsequently found the 0.03 are NLA

[arrow]

What do you mean they kept getting 0.003 ?

[nikfubar]

Three times I ordered the 0.03mm shims & 0.003 ones kept arriving, after this I asked them to find out what was going on & they came back with, they had been sent the 0.003 as the 0.03 were NLA & suggested I used 10 of them to get the clearance I needed, t**ts so I did as you suggested & sanded down a thicker one.

[arrow]

0.003mm is 3 microns. A ciggy paper is 30 microns. If a 3 micron shim did exist me thinks only NASA would be using them.

[nikfubar]

It is the thickness of a fag paper