Can i use AMSOIL SYNTHETIC SAE 20W50? for my 2006 road star silverado xv1700

Question edited for clarity, it a 'Road Star', not a 'roadster'.
Question moved to model category.

Here is your 605 page Service Manual in the second link, and here is specifically 'wiring'.

https://www.google.com/search?q=2005+yamaha+road+star+1700+wiring+diagram

XV1700 Service Manual

RsWarriorDocs.com http://www.rswarriordocs.com > manuals > War... PDF XV1700P/XV1700PC SERVICE MANUAL: LIT-11616-15-37 (5PX-28197-10) ... This manual was produced by the Yamaha Motor Company, Ltd. primarily for use by Yamaha ...
605 pages

..

check the Yamaha forums. You could possible have some clutch slipping if you use the wrong oil.

G'day.
If the previous owner used full synthetic oil then I recomend you do so too.
As a general rule it is not recomended to mix synthetic & mineral oils together.
Also as a general rule-most synthetic oils are of a higher quality & performance over mineral or semi synthetic oils.
You technicaly can use a non synthetic oil, but you would need to drain it all & also replace the oil filter,before re-filling with mineral or semi synthetic oil.
Hope this helps.
regards Andrew Porrelli

Differential, Front......GL-5
All TEMPS......80W-90 [5] [6]
SAE 80W-90 Synthetic Gear Lube (AGLQT)
SEVERE GEAR 75W-90 Synthetic EP Lubricant (SVGQT)
75W-90 Synthetic Long Life Gear Lube (FGRQT)
SEVERE GEAR 75W-110 Synthetic EP Lubricant (SVTQT)
Differential, Rear......GL-5
All TEMPS......80W-90 [5] [6]
SAE 80W-90 Synthetic Gear Lube (AGLQT)
SEVERE GEAR 75W-90 Synthetic EP Lubricant (SVGQT)
75W-90 Synthetic Long Life Gear Lube (FGRQT)
SEVERE GEAR 75W-110 Synthetic EP Lubricant (SVTQT)
Transfer Case,W/ NV Elec......SLF [7]
No AMSOIL Product Recommendation
Transfer Case,Others......GLS [8]
Torque-Drive Synthetic Transmission Fluid (ATD1G)
Synthetic Multi-Vehicle Automatic Transmission Fluid (ATFQT)

Standard Differential, Rear 8.8 and 9.75 RG......GL-5
All TEMPS......75W-140 [3]
SEVERE GEAR 75W-140 Synthetic EP Lubricant (SVOQT)
80W-140 Synthetic Long Life Gear Lube (FGO05)
Limited Slip Differential, Rear 8.8 and 9.75 RG......GL-5*
All TEMPS......75W-140 [4] [3]
SEVERE GEAR 75W-140 Synthetic EP Lubricant (SVOQT)
80W-140 Synthetic Long Life Gear Lube (FGO05)
Differential, Front 8.8 RG......GL-5
All TEMPS......80W-90
SAE 80W-90 Synthetic Gear Lube (AGLQT)
SEVERE GEAR 75W-90 Synthetic EP Lubricant (SVGQT)
75W-90 Synthetic Long Life Gear Lube (FGRQT)
SEVERE GEAR 75W-110 Synthetic EP Lubricant (SVTQT)
Transfer Case,......MA
Synthetic Multi-Vehicle Automatic Transmission Fluid (ATFQT)
Torque-Drive Synthetic Transmission Fluid (ATD1G)
Fluids
Power Steering Fluid......MA
Synthetic Multi-Vehicle Automatic Transmission Fluid (ATFQT)
Power Steering Fluid......MA
Torque-Drive Synthetic Transmission Fluid (ATD1G)
Brake Fluid......HB
AMSOIL Brake Fluid DOT-3 (BF3SN)
Clutch Fluid......HB
AMSOIL Brake Fluid DOT-3 (BF3SN)

Try looking at the electrical schematic at the link below, just choose your specific model.

http://www.bikebandit.com/2007-yamaha-xv1700-motorcycle-parts/oem-parts/s/mg8735

LUBRICANTS & FLUIDS
Engine Oil
Grade 1......API*
100% Synthetic 0W-20 Motor Oil
SAE 5W-20 XL Synthetic Motor Oil
SAE 0W-30 Synthetic Signature Series Oil
Above 9°F......15W-40
Above 0°F......10W-30
Above 19°F......20W-50
All Temps......5W-20
Manual Transmission,.....GL-4
75W-90
Synthetic Manual Transmission and Transaxle Gear Lube 75W-90
Automatic Transmission,4 Speed AT.....SLF[1]
Synthetic Automatic Transmission Fluid
Fluids
Power Steering Fluid.....PS
AMSOIL Universal Synthetic Power Steering Fluid
Brake Fluid.....HB
Series 500 High Performance DOT 3 Brake Fluid
Clutch Fluid.....HB
Series 500 High Performance DOT 3 Brake Fluid

1. Kia automatic transmission fluid, SP-III.


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