Schumann Motor Works

Schumann Motor Works Specializing in vintage motorcycle cylinder head services and custom valve train components.

CB750 K0 sandcast head 1 of 3 finished. All threaded holes good in this one.
06/11/2026

CB750 K0 sandcast head 1 of 3 finished. All threaded holes good in this one.

3 sets KZ1000 OEM type iron guides wrapped up.
06/10/2026

3 sets KZ1000 OEM type iron guides wrapped up.

SOHC CB750 valve guide batch finished. 3 sets of them going in K0 sand cast heads.
06/09/2026

SOHC CB750 valve guide batch finished. 3 sets of them going in K0 sand cast heads.

1975 Z1 head build back to stock specs with new bronze guides and OEM type valves.
06/08/2026

1975 Z1 head build back to stock specs with new bronze guides and OEM type valves.

Meowy McToebeans has completed his post service test ride and confirms it now does power wheelies in not just first, but...
06/05/2026

Meowy McToebeans has completed his post service test ride and confirms it now does power wheelies in not just first, but second gear as well.

Four more sets of Z1/KZ valve guides finished.
06/05/2026

Four more sets of Z1/KZ valve guides finished.

Clutch replacement and cam cover gasket service on the GS1100E. Pretty sure I’m the first person to ever remove this clu...
06/04/2026

Clutch replacement and cam cover gasket service on the GS1100E. Pretty sure I’m the first person to ever remove this clutch cover, gasket looks factory from 1982. Cam cover was leaking oil badly and did a valve adjustment while I was in there.

3 sets of oversize intake valves for XR250R wrapped up. 30mm head 5mm stem.
06/03/2026

3 sets of oversize intake valves for XR250R wrapped up. 30mm head 5mm stem.

1979 XR500 all wrapped up. Made new valves with intakes 1mm oversize, bronze guides, spring seats with the correct inner...
06/02/2026

1979 XR500 all wrapped up. Made new valves with intakes 1mm oversize, bronze guides, spring seats with the correct inner step for the RD spring kit. Updated to a Yamaha spec low profile viton seal which along with the new guides gives .065” retainer to seal clearance at max lift. Reworked the porting optimized for the new valves.

1973 CB500 head build. Made all new stock replacement type valves.
06/01/2026

1973 CB500 head build. Made all new stock replacement type valves.

Address

8613 SE Strawberry Lane
Milwaukie, OR
97267

Telephone

(503) 939-7395

Website

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