Breva1100/Norge Valve Clearance

[Kev M]

I'm sorry to ask such a basic question, but I only do this once a year or so, and my notes are confusing me.

I can't find specs in the owner's manual.

Guzziology basically says all big twins are In: 0.004" in. (0.10mm) / Ex: 0.006" (0.15mm) if you're following world specs.

The PDF Workshop manual (in English) agrees (which makes me wonder if it was meant for the US or just an English translation of the world spec guide).

And I'd have followed those specs (as I do on my Jackal), if I hadn't found a note on my service sheets that I wrote which claims the EPA label (which I can't find right now, was it on the seat?) said THOSE figures were the tighter US spec, and that there are looser world specs of In: 0.0059" (0.15mm) / Ex: 0.0078" (0.20mm).

My notes seem REALLY specific with the measurements.

I was going to ignore them and follow Guzziology and the PDF manual, until I measured the first intake valve and realized it was set way too loose for the 004" spec, which got me thinking maybe I followed the 0.006" spec.

What do you guys use?

Any idea where I pulled those other specs from?

Kev

PS - didn't there used to be a detailed valve adjustment thread here, I searched a couple of times but couldn't find it.

 

[londonrob]

Your right with the 0.10 and 0.15 for inlet and exhaust, i remember seeing it on a thread a long way back, and also confirmed by a guzzi mechanic.
when i checked mine at 10 thou miles they were bang on.

 

[Kev M]

Thanks, makes me feel better going with them - I got the valve covers opened now, so I'll tighten them up a bit and go with those specs.

I'm still curious where the heck I got those other specs from... I'll post if I figure THAT out...:silly:

 

[MurphyPeoples]

Was there ever a "2V Adjustment" post like the excellent "4V" adjustment post Pete Roper made?
Murphy

 

[Kev M]

MurphyPeoples wrote:

Was there ever a "2V Adjustment" post like the excellent "4V" adjustment post Pete Roper made?
Murphy

A year ago when I did it the first time there was a large thread with a step-by-step adjustment.

Not sure who penned it - maybe Graham, maybe a compilation of people, I forget.

 

[john zibell]

Kev,

The "original" US spec for the newer bikes like the 1998 I had were .002 inch intake and .004 exhaust. Reasonable people used the world spec of .004 and .006 inch. The numbers you are quoting are similar for the old round heads, .006 and .009, or just set both to around .008. But then the big valve 1000 engines go .008 and .010 inch. So there are many specifications to go around.

 

[Kev M]

john zibell wrote:

Kev,

The "original" US spec for the newer bikes like the 1998 I had were .002 inch intake and .004 exhaust. Reasonable people used the world spec of .004 and .006 inch. The numbers you are quoting are similar for the old round heads, .006 and .009, or just set both to around .008. But then the big valve 1000 engines go .008 and .010 inch. So there are many specifications to go around.

Yeah, I've got a Jackal also, so I'm aware of the 02/04 inch US specs, even though I've always ignored them and set them at the 04/06 inch world specs.

What's confusing me is that I wouldn't have written down that 06/08 inch spec for the B11 if I hadn't thought it was a good source, so it's just got me confounded that everything I'm looking at is saying 04/06 inch for the B11 and I can't find where I got the looser spec. :side:

 

[GrahamNZ]

Yes I did post about adjusting valve clearances. Here it is again.

Breva V1100 tappet adjustment

Although the Workshop Manual calls for the petrol tank to be removed that isn't necessary, which is good because disconnecting the rather fragile "quick release" fuel line is tricky unless you know what you're doing.

However it is necessary to raise the front of the tank for access to the top rocker cover screws. To do this just remove the rear tank retaining bolt and the front-of-tank air duct then move the tank back a bit, raise the front and move the tank forward again so it rests on top of the front locating rubbers each side. For even more access, raise the rear of the tank onto a 45mm thick block of wood.

tank raised for rocker cover top screw access

• Remove the outer spark plug lead covers, rocker covers and outer spark plugs.
• Remove the round plug over the crankshaft front nut and turn the engine, always forwards, with a 24mm socket and ratchet.

• Check the clearances on each cold cylinder separately with a feeler gauge with the piston at TDC on the firing stroke and both valves closed. To find this, turn the engine until the inlet valve has just closed then check the rise of the piston to TDC by shining a torch into the spark plug hole. It's easy.
• Use an 11mm ring spanner and small adjustable spanner to set the tappet clearance between the rocker foot and valve stem top. Inlet 0.10mm and exhaust 0.15mm. There seems to be a tendency for the clearances to increase, which is better than the opposite. In my case clearances had increased by 0.05mm maximum in 9,000km.
• If the cover gasket has been damaged or leaking, fit a new one. They're cheap, so it's wise to have a spare pair available before you start.
• At the same time (10,000km intervals) the handbook calls for new NGK BPR6ES spark plugs to be fitted.

Graham

 

[Kev M]

GrahamNZ wrote:

Inlet 0.10mm and exhaust 0.15mm. There seems to be a tendency for the clearances to increase, which is better than the opposite. In my case clearances had increased by 0.05mm maximum in 9,000km.

another "vote" for 10/15mm cool - that's where I set-em.

My clearances also increased over the last 6k miles - by about 0.05mm/valve...

Sounds pretty normal.

Kev

 

[john zibell]

Kev M wrote:

john zibell wrote:

Kev,

The "original" US spec for the newer bikes like the 1998 I had were .002 inch intake and .004 exhaust. Reasonable people used the world spec of .004 and .006 inch. The numbers you are quoting are similar for the old round heads, .006 and .009, or just set both to around .008. But then the big valve 1000 engines go .008 and .010 inch. So there are many specifications to go around.

Yeah, I've got a Jackal also, so I'm aware of the 02/04 inch US specs, even though I've always ignored them and set them at the 04/06 inch world specs.

What's confusing me is that I wouldn't have written down that 06/08 inch spec for the B11 if I hadn't thought it was a good source, so it's just got me confounded that everything I'm looking at is saying 04/06 inch for the B11 and I can't find where I got the looser spec. :side:

Kev,

Did a little digging. The 0.006/0.008 is for the small blocks including the 750 Breva.

 

[Kev M]

john zibell wrote:

Kev M wrote:


What's confusing me is that I wouldn't have written down that 06/08 inch spec for the B11 if I hadn't thought it was a good source, so it's just got me confounded that everything I'm looking at is saying 04/06 inch for the B11 and I can't find where I got the looser spec. :side:

Kev,

Did a little digging. The 0.006/0.008 is for the small blocks including the 750 Breva.

Grazie,

Yeah someone posted that yesterday in the same thread I started at Wildguzzi - and obviously that's a possibility. But my notes said EPA label, so I gotta find out where the label is/was and just check it for shytes and giggles. I'm thinking it was on my OEM seat which is boxed and on a shelf high enough I need to get the ladder...


:silly:

 

[Holt]

Probably guilty.
Yes the 750 is 0.15/0.20.

Just checked a couple of shop manuals for the 1100 Breva (seems to be at least 3 or more for the 1100) over at the Guzzitheque. Both said 0,10/0.15 for the 1100.

Sorry for the confusion, Kev.

 

[Kev M]

Holt wrote:

Probably guilty.
Yes the 750 is 0.15/0.20.

Just checked a couple of shop manuals for the 1100 Breva (seems to be at least 3 or more for the 1100) over at the Guzzitheque. Both said 0,10/0.15 for the 1100.

Sorry for the confusion, Kev.

Nah, you didn't cause any confusion - I did that all by myself, probably a year ago, but just noticed it now on my notes :silly:

 

[Moto Fugazzi]

Here's a how to with pics.

http://pexi.blogs.com/MGBreva_ML_i011.pdf

Very simple to do. Good idea to have extra gaskets on hand. Some people put grease on both sides of the gasket so that they don't stick and then have to be scraped off on the next adjustment.

 

[Chuck in Indiana]

IIRC, Pete wrote a thing on the big blocks, and ended up saying he thought .005/.007 was a good compromise. :lol: At any rate loud valves are happy valves, and I wouldn't worry about a thousandth..

 

[crswa]

I used this procedure last night. I've never done valves before. Very simple and easy. In fact, changing the inner set of plugs turned out to be way harder. I won't feel any trepidation about doing it myself next time. Thanks everyone.

(If only my wife's Ducati was as easy to adjust. I will NOT be attempting that one by myself)

 

[Penis Rotor]

The most important thing to remamber is why you are setting the valves with any clearance at all. It's all got to do with expansion. As the various parts of the motor heat up they expand. The Squarefins all use alloy rocker carriers, the roundfins use cast iron rocker carriers. all the motors use alluminium alloy pushrods and all use steel valves. Although the various valves may differ a bit in length the amount of difference that they will expand will be very, very small. All of them will, effectively, get *about* as hot as each other regardless of what engine they are in so the variation will not be overly effected by heat.

Cast iron expands less than alluminium. That means that with the engine COLD you have to set the clearances on a roundfin engine slightly wider than you do on a squarefin to ensure a 'Safety Margin'. The whole idea of the clearance is to ensure that a.) the valve isn't held off its seat when the engine is running because if it is the burning charge in the chamber will escape past the edge of the valve and burn the margin so that the vlve will then not seal and eventually the engine will cease to run as the charge can't be compressed and b.) to prevent the cam follower 'Riding' the cam. There has to be a time when the follower is on the base circle when oil can get between the spinning tappet and the cam lobe. If there isn't the tappet and lobe will run 'Dry' and rapid wear will result.

Ideally you want to have a clearance that will allow the valve to seat correctly and will also allow oil betwixt tappet and lobe. Too small and you get the problems noted above. Too large and you will get a.) excessive valve noise and, in some cases there is a risk that too wide a gap will allow the tappets will miss the rampings on the cams and hammer the flanks. This is not so much of a problem with the pushrod motors but the 8V cams seem to have very minimal ramps and too big a clearance is, I'm sure, one of the reasons for the early cam failures.

Pete

 

[Dah-Dit]

+1 Thanks for that thorough explanation. I've learned something new today.