Aye Double Diamond,
A 1991 SRX400 engine is identified by the code '3VN' or '3VN' in front of the specific unit number, stamped into the ridged area on the upper rear right hand case.
A 1991 SRX600 engine is identified by the code '3SX', located as for the 400cc engine.
A 1991 SRX400 monoshock was sold with an electric starter. I believe (and stand to be corrected
) that a monoshock fitted with a kickstart engine is a hybrid.
I too have a 1991 SRX400 monoshock fitted with an alternative engine that is a 1990 XT600E engine, with the engine prefix '3TB' that indicates that it is a 1990 engine.
For a full and comprehensive article upon model codes attributed to the SRX range of motorcycles, I would recommend reading this article:
SRX_model_codes I suggest that this website is worthy of a detailed view.
The following is a link to the Fowler's spare parts web list concerning the SRX400 model:
Fowler's_SRX400_parts_list Depending upon the model year selected, the relevant alpha-numeric code will be displayed.
I realise that this may raise more questions than it answers, but hope that it helps you in extracting the required letter from Yamaha (UK).
My regards, Bill
