Quantcast

the differences between the 350/400 air cooled motors.

Yamaha Raptor 350 & Warrior Forum

Help Support Yamaha Raptor 350 & Warrior Forum:

duneracerweston

Well-Known Member
Joined
Jan 27, 2011
Messages
6,088
Reaction score
7
Location
Brownsboro Texas
I mainly want to make this thread as a answer to what interchanges, the differences, and such to hopefully answer some of the common asked questions on these parts. bare with me this will take a minute.
 

duneracerweston

Well-Known Member
Joined
Jan 27, 2011
Messages
6,088
Reaction score
7
Location
Brownsboro Texas
as a bit of a introduction, I've been crawling all over these motors for about 14 years now, i have built more then a few record holding hp motors and am still steadily developing with these motors.



most of this will be referencing fit to the warrior 350 motor specifically. if you have questions of it switching the other way leave a comment.




the yfm350 motor is the Yamaha designation for their primarily air cooled 2 valve motors.

the yfm350 in particular has two variants, chain drive and shaft drive. they have more in common in name then the actual motors. some parts can be easily swapped over such as head, everything in the head, valvetrain, cam, timing chain, cylinder and piston. the rod is the same but the clutch side half of the crank is different and non swappable with out modification. the shift shaft is usable but must be cut in order to fit the warrior clutch cover. the oil cooler from the early 350 big bears with the 2 piece oil filter housing will cross over but causes interference and have become hard to find, however zoom zoom makes a oil cooler kit that is a replica of this setup with a draw back of shifter interference if you run a direct shifter. drw also makes a adapter that solves the size issue but is not a full kit and is a bit more costly.




the 400 shares even less with the warrior as far as direct fitment. the heads are identical even though the part numbers differ the design, ports, valve train and cam are all the same. the cylinder will fit but is taller then the warrior so the piston will never reach the top thus causing a lack of compression. it may fit but it wont just drop right on.

that is basically the conversion parts. the carbs are different, nothing jaw dropping performance change wise, the exhausts are completely different so that's a no go on those either.


now back to that cylinder, it is usable, although it takes a longer rod to do so. CP-Carrillo will make them and i have the specs on both the rod for a stock stoke motor or a stroker using the 4mm hot rods crank.



nothing that switches over from one to the other will make a warrior a "400" a 400 cylinder will not make it a 400 and the crank will most certainly not work with a warrior motor.






In short the heads swap, everything in the heads swap, the cylinders can but not a direct bolt on for the 400 cylinder. and they use the same pistons. that's about all that interchanges between these 3 motors.

before anyone asks the wolverine 350 has more in common with a big bear 350 then a warrior.

electronics do not swap over, and flywheels are timed and weigh different then the warrior.

any questions drop them down below.
 

Latest posts

Top