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American Bosch, Bosch magneto ZR4 vs DU4 Interchangable?

G

glenshep

Guest
American Bosch, Bosch Magneto ZR4 vs DU4. What are the functional differences between these two mags, can the DU4 be used in place of the ZR4?
 

FWurth

One Millionth Post
Last Subscription Date
07/29/2019
Not real familiar with the ZR 4 but in general if the rotation and impulse lag angle is correct also the coupler matches, there should be no problem. Some folks are real particular to have the right OEM parts on their project but down here in the real world we use what fits in order to get it running, we can get picky later if and when the originals show up. F.J.W.
 

stufforbud

Subscriber
Last Subscription Date
09/17/2019
There are some other slight differences, but mostly the ZR is just more weather proof than the DU because of the cover over the leadout tower and the material between the magnets. I have found no dimensional or performance differences.
 
G

glenshep

Guest
Looks the same, spins and matches up the same, see if I can get this old girl fired up then go back to what was with it.
 

Craig Gillingham

Registered
Last Subscription Date
12/04/2017
I'd think a Bosch DU4 and a ZR4 should generally interchange. When you're looking at the Interchangeability between magnetos, the important things are the bolt pattern (in this case, a 50mm square 4 bolt), the spindle height (45mm) and offset from the end of the input shaft to first row of mounting bolts (80mm), as well as the input shaft itself (large size 1:10 taper), and the input shaft thread size (3/8" Whit). All those things are the same between a DU4 and a ZR4. The ZR4 is a bit taller than the DU4, sometimes this may make a difference where clearance is an issue underneath a manifold, or fitting between linkages. But otherwise, generally, as stufforbud has said, a DU4 and a ZR4 will interchange.
 

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