Dear All, I have the heads off my Breva1100 and stripped down.
Question: with the valves loose in the guides and in a roughly ‘valve open’ position, how much play is ok?
One valve can rattle about approx 1mm which must be too much, others are about 0.5mm which I also think is beyond limits?
Also, if I’m going to renew any, should I do all four as a matter of course?
I would suggest that as one of them is clearly worn that you replace them all whilst you have it apart, then you can forget about them for many miles ahead.
Ditto the comment above, change all four whilst it’s apart.
How many miles you done on it now? What made youy strip the heads down, oil consumption, noise or what?
Ta
Jim
You need to check the valve stem for wear. Measure with a micrometer the wearing part of the stem against the non contact part. Refer to spec in manual. Re guides. Stick the valve in the guide raise it about 5mm from the seat. Try to wiggle it side to side. There should be play but barely perceptible. Oil the stem with engine oil repeat and lightly try to wiggle it with the oil you should feel no play as the oil has taken up the clearance. Any visible movement is too much. Valve stems and guides can wear. The fit is really important. If replacing guides valves get them cut not ground (using paste) to spec.
Thanks for the replies. Here’s some answers to questions;
The heads were off to put some thread inserts in some failed holes.
Finding the valve wear was a side issue. The bike has done about 86,000 now and gave no evidence of valve troubles - except maybe the dark discolouring of burnt oil around the valve gear.
On both sides it’s the exhausts that are worse. I had already done as suggested and with the valve open about 5mm it can move about 1mm side to side. The inlets are much less but as you say, probably best to replace all. The valve stems show and measure no wear along their full lengths.
Pleasingly the pistons look good and the bores still show their honing marks.
Good to know. Disappointing to have some wear at this mileage, but I suppose it is not that bad for an air cooled engine?
I suppose it’s not so bad. I would never have guessed there was a problem if I had not had the heads off for the other job. The engine was running fine with no hint of valve problems.
Getting the heads sorted soon. New guides purchased from Gutsibits, not as expensive as feared.
I have found a place to do the work quite nearby in Melksham, called MX Zone.
Find them online at Mxzone.co.uk
Looks like they should do a good job. I will report back when it’s done.
I have got to the reassembly of my Breva 1100 heads but can’t find a clear value anywhere for the torque values of the head fasteners? The 4 nuts on the rocker gear and 2 cap head bolts (top/bottom). All M10.
There is a manual available here
http://www.guzzitek.org/gb/ma_us_uk/1100/Breva1100_102005_Atel2(GB).pdf
Torque info in the technical data
Other manuals etc also available if that is not your model
http://www.guzzitek.org/gb/atelier_gb.htm
Thanks Don-Spada, I’ve been through these but this is what I mean by “not clear”.
I see what you mean, It’s not clear. The most important thing is that theyare all equal. My guess would be the Stud bolt at 35Nm, but I would be guessing and they are recorded as m8.
Is this a supplement manual to a general 1100 manual?
Continuing on with this. When I come to reassemble things, dropping the pushrods down their holes, the exhaust one drops into a close fit at the camshaft end, presumably the cam follower. The inlet one doesn’t. It’s a loose rattle fit down there. Is it possible that the cam follower has gone somewhere - on it’s own? I didn’t remove any of them!
HELP!
Can you shine a light down and see what is going on?
Or maybe one of these would help? A tiny camera that connects to your phone. The quality is fair, not brilliant
https://www.ebay.co.uk/itm/1-10M-6-LED-Waterproof-Android-Endoscope-Borescope-Snake-Inspection-Camera-video/183070377332?hash=item2a9fd84574:m:mu775fNZtv99y-PTXpn14bg
There is no possibility the guide has gone somewhere. Put the push rods in and turn the engine over slowly if the rods go up and down that will do. If you are worried about the barrels moving these can be clamped down on a barrel stud using a nut and some spacers to press down on the barrel.