XJ 600 Diversion engine number

[msdavidson]

Hi I've just joined.

I've got a 1992 Diversion that I built up from a box of bits 5 years ago. I use it as a winter bike and it has now done 59000 miles. It has always had a clunky gearbox  - the worst I've ever experienced - and the timing chain tensioner has no adjustment left so I've decided to change the engine for a lower mileage one. The engine in the bike has a number that starts with 4BR which is the Yamaha model number. The new engine I've got starts 4DU and seems identical in every way.

What is Yamaha model 4DU and what are the differences between the two engines.

Can any one help please?

msdavidson 

[Oldfjman]

I'm no expert and I'm not sure what any specific differences there might be (other than emissions related stuff - carbs, exhaust ignition module etc) but I think that the 4BR was the European model designation (XJ600S/N  Diversion) and the 4DU was used for USA models (marketed as the Seca II). So I'm guessing your newer engine came out of an American bike imported here.

Maybe there were some valve or cam differences, but tbh, I doubt it.

Double checking on eBay seems to confirm that items from the USA, or listed as Seca II parts seem to have the the 4DU model number and those from Europe (priced in £ or €) or listed as Diversion parts generally have the 4BR model number.

this table below was taken from some info in German

	XJ600S Diversion	XJ600N
Model Year	1991–2003	1993–2003
Veh Type	4BR(A)/4BR(B)/4LX/RJ01	4BR(A/B)/4LX/RJ01
Design Type	Half Faired	Naked Bike

 

The link here should take you to the USA owners manual for the Seca II - which only lists the 4DU reference

https://dd5394a0b8ca8e97ba29-abf76f3d91a2125517d6c7c409f095c7.ssl.cf1.rackcdn.com/content/common/manuals/1994/seca_2_1994_LIT-11626-08-87_1813.pdf

Edited November 16, 2018 by Oldfjman

[msdavidson]

That's useful. Thanks for the info.

msdavidson