i do not know why there are two carbs, but they are not primary and secondary they both work at the same time. i have watched it with no filter. the reason why they stagger the jets from the factory, (bigger on right smaller jet on left) is because the right ports are a little larger and flow smother. i would guess by that design it would give a broader power band



raptorboy673

 

I got my motor back, that is good enough for me...the head gasket blew after about 10 hrs[img]i/expressions/face-icon-small-mad.gif[/img]
... I got it apart now . It takes as long to change a head gasket on a ds, as it does to re jet my raptor.

I hope Don has started settling up with the other guys....

 

Okay folks the reason for two carbs.... better bottom end than 1 big carb while still flowing adequately for higher RPM's. The right is jetted fatter because it feeds 2 intake valves while the left feeds 1 intake valve. There are 3 intake and 2 exhaust valves. I'm not an engineer so I cant comment on Yamaha's laziness in design. I will say however that the trans changes for 02 are certainly an improvement over the '01 and Yamaha should be ashamed that they havent tried to accomodate '01 owners with at least a parts discount to upgrade it..... Btw, Mojave's have a single carb. DOHC is dual overhead cam, not carbs.

 

45, I wasn't saying DOHC stood for double overhead carbs, I was saying that maybe the secondary carb kicked in at a certain RPM JUST LIKE the second cam on the mojave did. I know the mojave had only one carb, but I was just describing that feature on the mojave to compare it to the point I wa trying to make about the Raptor. But I think I've been proved wrong anyway.