1984 porting updates

Marc Machine · Post by **Marc Machine** » Mon Jan 19, 2009 9:35 pm

If I have the 84 updates done on my 83 Vmax will it affect everyday riding and dependability? I don't want to carry a tool bag with me every time I go riding. Could it still be considered stock or just updated to what Yamaha should of done back in 83? I don't want to race this sled, it isn't a racing modification is it? Should I just keep the stock 38mm carbs and just clean them up? I read about the guy who bored them to 39.5mm, is that a good idea or will it need constant tinkering?

Post by **Vmax540** » Tue Jan 20, 2009 12:34 am

Bender and Riechards considered Yamaha's porting to be a hot trail setup and would go futher for racing applications. I'd say keep an eye on your jetting, plugs, piston wash and run a good grade of gasoline. Can't see Yamaha recommending a porting that was unreliable ?

vmax-540 · Post by **vmax-540** » Wed Jan 21, 2009 12:29 pm

I had the update porting done years ago to my Vmax ,and it ran good on the trail ,you lose a little low end torque but when you get your clutching dialed in it feels as good or better down low and pulls like a son of a bi--- up thought to top end. Yamaha all most put it on the production sled but at the last minute decided not to. It has the same port timing as the 81 SRX but with the larger engine makes it a lot better engine then the SRX . I think that the stock 38s are a lot easier to dial in then the 39.5s.

Marc Machine · Post by **Marc Machine** » Wed Jan 21, 2009 7:29 pm

Thanks for the information Jeff, I had decided not to touch my carbs and leave them stock. Still ready the forum section alot to try and determine what I'm going to do regarding the clutching. 108 EXP, 108c, rebuild my original 102c? I want to keep my stock secondary, maybe get a new spring but that's about it. What do you think?

vmax-540 · Post by **vmax-540** » Thu Jan 22, 2009 7:13 pm

If it still has the 102 on I would just have it rebuilt,new bushings and springs and what ever it needs . There is a lot of performance to be gained just by fine tuning your clutches ,I would also check the secondary clutch for worn bushings as well . You can do a lot with the stock clutches just spend the time and try different things and I think you will be pretty happy.