Guide & Valve Seat Replacement

[n3303j]

The T3 is spread across the NEW (YAY!) workshop. Moved to a new house November 2023. Workshop build finished November 2024. Everything waited over a year. Poor motorcycles.



March 2025 the T3 showed 30% compression leakage on a compression differential test. It hissed at the oil fill hole. So I have rings on order and am cleaning up the machine while awaiting ring delivery.

Cleaned the heads and pulled the valves. Intake valves and seats look excellent at 100K miles. Both exhaust valves and their seats are quite "textured". Seats look fairly worn too. So I'm probably in for valve and seat (maybe guide too) replacement. Surprised they sealed as well as they did.

My question:

Up to now I've always used Memphis Motor Werks (Leo Goff) or Long Custom Mechanical (Randy Long) to do this type of service. Now I notice Memphis no longer lists motorcycle work on their website so they might not be available. Randy Long is very good at what he does so usually has a 6 month waiting list for his services. I'd like the work done sooner if possible.

Who else is doing a reliable job on this type of machine work for our vintage machines?

[guzzisteve]

Look for a guy that does V8's, same stuff basically their tooling works. I used a friend w/auto motor rebuilding shop. I found one real close to me here in GA. Hard to find an old school machinist.

[n3303j]

Look for a guy that does V8's, same stuff basically their tooling works. I used a friend w/auto motor rebuilding shop. I found one real close to me here in GA. Hard to find an old school machinist.

I get concerned about using automotive guys for this service as a number of the BMW /2 fellows (and later Airheads) had problems with heads reworked by car guys. Seems there's some magic in fitting durable components into higher RPM air cooler machines. Cars are cruising around 1,200 RPM now. I often keep it cruising between 3K & 5K RPM.

[PeteS]

Can’t help with a name but have used both those guys in the past. Leo must be pushing 90 by now. Never met Randy but he did my BMW heads a few times. Both craftsmen.

Pete

[guzzisteve]

Yes, i forgot about the BMV factor here. Trust as you wish.

[John A]

Some shops don’t have stones small enough.

[PeteS]

Stones are pretty old school. The best shops will have something like a Serdi seat cutter. I have some Neway cutters but can’t match professional work.

Pete

[John A]

Stones are pretty old school. The best shops will have something like a Serdi seat cutter. I have some Neway cutters but can’t match professional work.

Pete

Yeah, I was going to mention cutters but my mind was on old school. It’s a smaller combustion chamber than a lot of automotive engines and the outside diameter of the cutters and stones is where the trouble is.

[Dukedesmo]

When I wanted the valve guides replacing on my LM2 (due to a piston to valve incident) I was concerned that, according to my research, the heads are easy to damage whilst removing/refitting guides and NLA to purchase new if damaged so I opted for K-line valve guide liners.


Basically they bore through the existing guides and insert the K-line inserts which are supposed to be better than solid guides and are used in many motorsports (the place that did mine said they did them for Formula 1 racing teams).


Obviously a specialised job but no more expensive than new guides and they've been fine since.

[moto]

...
I opted for K-line valve guide liners.
...
no more expensive than new guides and they've been fine since.

Ditto

[PeteS]

I used to get my valves and guides from Kibblewhite. You might want to contact them to see if they do seat replacements. They have guides and valves for Nortons, BMWs and Guzzis so they are familiar with vintage twins.

https://www.kpmi.us/home.html

Pete

[n3303j]

Ditto

I'm looking for who, I have already decided on what.
At 79 years old I'm pretty sure a standard guides, seats & valves job will outlast my riding career. Especially as my mileage is spread over 3 machines.

[John A]

I’ve not been able to find a shop that does Klining. It’s been a few years but it seemed most shops around here never heard of it . Sounds like a good practice, especially on antique, irreplaceable heads

[BigDen]

All the way across the country in Petaluma, CA, I used http://www.enginedynamics.com/ when I had my T3 heads refurbished with Kibblewhite valves and guides a few years ago.  They did a nice job and have the right tools for the job.

Dennis

[Moparnut72]

When I worked in the radial engine shop I did all the valves. I used Neway cutters, being that the cylinders were one piece with with heads I had to use a wobbly. It was tough to get even pressure on the seats but it could be done. The seats had a 3 angle design so it was a pretty involved process. It would take me a couple of days to do a 7 cylinder engine. The seats came out very nice and on Wrights we tested with compressed air.
kk

[n3303j]

All the way across the country in Petaluma, CA, I used http://www.enginedynamics.com/ when I had my T3 heads refurbished with Kibblewhite valves and guides a few years ago.  They did a nice job and have the right tools for the job.

Dennis

Spent an educational half hour on the phone with Randy Long.  He will be doing my heads. Seems Kibbkewhite stopped making valves for the less popular machinery. That includes Moto Guzzi. Plenty of intake valves are available, but the higher stressed exhaust valves are sort of used up. Randy said he will come up with a suitable substitute.

[Antietam Classic Cycle]

Spent an educational half hour on the phone with Randy Long.  He will be doing my heads. Seems Kibbkewhite stopped making valves for the less popular machinery. That includes Moto Guzzi. Plenty of intake valves are available, but the higher stressed exhaust valves are sort of used up. Randy said he will come up with a suitable substitute.

I've been buying valves from Stein-Dinse/MG Cycle for all of my rebuilds. According to the guys at the machine shop, they're excellent quality. Never had an issue with any of the dozens I've installed.
 
https://www.mgcycle.com/index.php?main_page=product_info&cPath=68_127&products_id=342
https://www.mgcycle.com/index.php?main_page=product_info&cPath=68_127&products_id=343

I use the guides they sell as well.

[cappisj1]

A good quality shop can put valve guides in. Ask around to find the “go to” local shop. The MG and VW car crowd will know who to use.

[Frenchfrog]

I've been running two sets of k lined guzzi heads for many miles ...zero problems and IMHO a very good solution.