Head overhaul - where in UK?

5

500twin

New member
Location
South West
Hi Folks

I removed my Montjuic head to inspect the valves and deal with a leaking gasket etc [I have no history with my bike] Thankfully the head casting looks good, no cracks or valve recession but I would like a professional machinist to look it over and advise if seat/guide/valve remediation is required/possible. The exhaust valves look a bit eroded/sunken in the valve rim profile. Who are the people [or person] to speak to in the UK these days. Is it a Laverda specialist or general enquiry I need to make? I am based in the South West so either hand deliver within range of DT9, otherwise ship [with insurance!]

Also where should I look for head and barrel base gaskets?

All the best

David
 
Thorne engineers still have the gaskets on the list, that is where I bought mine- you would have to contact Rowan to find out whether he would supply to you.
I know he is trying to sell the whole of the stock but he may help you out . Stu
 
Hi
If you want to Stick to UK, Seager Engineering does endless heads and displays all his work on Faceache.
I believe he's repaired a Montjuic, mostly challenging/high end british repairs..
Makes his own guides, seats I think. Very capable outfit from what ive seen.

https://www.facebook.com/share/p/18MfXXY5fB/

Ebay currently has several combo's of 500 gaskets inc a full set from Italy, under the import tax threshold ( unless eBay adds vat).

Athena website may give you more specific part numbers for individual gaskets which makes searching more precise.
Of course, there are several operations in Europe that are well worth considering too.

Rob
 
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How thick are your valve shims ?
if mid-range 2.5mm +/-, just lap the valves in, no need for head work
but if they are under 2.0mm, you are going to need head work done
 
redax5 said:
How thick are your valve shims ?
if mid-range 2.5mm +/-, just lap the valves in, no need for head work
but if they are under 2.0mm, you are going to need head work done
Click to expand...
Mmm, good question. Hadn't thought about that as my valve adjustment frame of reference is 2 strokes/A series adjustable/Porsche hydraulic = no idea/no experience. Some more reading for me and a good excuse to buy a micrometer..
 
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500twin said:
Mmm, good question. Hadn't thought about that as my valve adjustment frame of reference is 2 strokes/A series adjustable/Porsche hydraulic = no idea/no experience. Some more reading for me and a good excuse to buy a micrometer..
Click to expand...
when buying the micrometer you need one that will fit inside the 500 shims, they have 6mm valve stems so not all 0-25mm micrometers will work on them, majority will not
 
I find using a thickness gauge far more convenient than a micrometer. Instead of constantly screwing to and fro, a lever lifts the measuring probe.

Something like these, randomly found on the www:
teclock.co.jp

Thickness Gauge - Teclock

teclock.co.jp teclock.co.jp

Lots of variants to choose from for all manner of applications. As Red has stated, probe diametre should be less than 6mm. One probe end also needs to be flat, the shim bore usually has a dimple in the centre that needs to be bridged.

With digital indicators becoming really affordable, I'd opt for one of those. Especially if not used to working with such tools, a measurement can easily be misread on analog indicators with primary and secondary dials. Set the digital to zero, the result is spelt out in big, bold digits, no room for misinterpretation.

I was too broke many years ago to afford such specialist kit, so I made my own. Has a dial that can be read by dummies. Still in use 40 years on.

DSCN2128.JPG

piet
 
sfcpiet said:
I find using a thickness gauge far more convenient than a micrometer. Instead of constantly screwing to and fro, a lever lifts the measuring probe.

Something like these, randomly found on the www:
teclock.co.jp

Thickness Gauge - Teclock

teclock.co.jp teclock.co.jp

Lots of variants to choose from for all manner of applications. As Red has stated, probe diametre should be less than 6mm. One probe end also needs to be flat, the shim bore usually has a dimple in the centre that needs to be bridged.

With digital indicators becoming really affordable, I'd opt for one of those. Especially if not used to working with such tools, a measurement can easily be misread on analog indicators with primary and secondary dials. Set the digital to zero, the result is spelt out in big, bold digits, no room for misinterpretation.

I was too broke many years ago to afford such specialist kit, so I made my own. Has a dial that can be read by dummies. Still in use 40 years on.

View attachment 108421

piet
Click to expand...
Mmm you remind me I do have a dial indicator. I like your home made version.
 
redax5 said:
How thick are your valve shims ?
if mid-range 2.5mm +/-, just lap the valves in, no need for head work
but if they are under 2.0mm, you are going to need head work done
Click to expand...
Mmm, our [digital vernier] survey says...possible head work?

1792163438855.png
 

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My comments are based on triples experience but may extend to montjuic.

Measure also the valve lengths and find the spec... if the valves have been tipped (because of a lack of clearance) this would also need to be subtracted from your shim measurements.

Conversly, if the valve head has been refaced on a valve master or the valves are simply worn out, that would work in your favour with new valves ( check stem diameter also)

My experience with valves is no two makes are ever the same.

Your shims are fairly consistent, thats a positive.

Rob
 
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