The best sprocket pair for the Yamaha Seca 400 often depends on your riding style and desired performance. A common recommendation is a 15-tooth front sprocket paired with a 45-tooth rear sprocket for a good balance of acceleration and top speed. However, for more aggressive riding or quicker acceleration, you might consider a 14-tooth front sprocket. Always ensure that the sprockets are compatible with your bike and your riding needs.
try the yamaha seca store.
Try one off of a yamaha seca 400
ebay
Yes, a round headlight will fit on a Yamaha Seca. Just be sure that the model and specifications match what will fit into the mounting brackets.
81hp
2
The spark plug gap in a Yamaha Seca is 1/2. It can be easily obtained and is very affordable and likely to be replaced by the owner. It is a quick replacement.
There is NO WAY a stock Seca 2 will do 140. About 115-120, which isn't bad.
the difference is the Yamaha is better
Sure anything is possible with a little ingenuity - Yamaha parts especially older models can be swaped without too much fuss.
Maxim 400
I have a 92 seca 2 with a 600cc motor, and it takes 2.6 quarts of oil to fill it up.