Recipe for a FAST 350X?

[All X's]

With so many people asking how to do up a 350x can we get some engine combinations that are tried and tested? so far for exhaust supertrapp is king. for cams webcams. For crank i have powroll . shaved (lightened) flywheel ,aluminum sprockets. is there anything I'm forgetting??? How about lightweight tires and rims? I have a kenda front max for the front and maxxis 4-snow for the rears.

[X053]

I don't know about the aluminum sprocket. Unless you got lots of money and like changing them all the time.

You might try a 400EX carb! I like mine! :thumbsup:
And maybe a good port and pollish job

[SWIGIN]

my favorit all around 350x motor is a 10.25-1 piston, megacycle cam full race grind, full port work, 38mm round slide carb, degreed cam for type of rideing, custom shorty head pipe (quad only), open air box with a k&n, custom aluminum intake (stock is only around 34-35mm), clearenceing the cly near where the valves are to unshroud them, and of course hard faced rockers and HD valve springs.

this is what id call a mild or normal built motor...but its a fun reliable combo

[All X's]

sounds like a winning combination alright.

[random-strike]

i had a 11:1 piston in mine before just that alone made a huge difference

[All X's]

I don't know about the aluminum sprocket. Unless you got lots of money and like changing them all the time.

You might try a 400EX carb! I like mine! :thumbsup:
And maybe a good port and pollish job
I use PBI aluminum rear sprocket, and no problems yet, and they claim stronger than steel.

[NOS_350X]

For just bolt on's
A 400ex carb and a uni/K&N, and a s-trapp pipe And lightened flywheel will be your best bang for your buck.
If your too cheap to buy the s-trapp The 450r exhaust and 400ex headpipe mod are CHEAP and for what they are very good.

I have tryed sooo many compinations its hard to list them. It depends on how you want the power.

I have gotten very decent power out of the stock cam. I would port before i put a cam in the bike.

The best thing to do is to find out what mods do what to the motor, For example, What are you goign to loose/gain from going to a large carb. How about compression. Certain cams dont go well with high comrpession, Some of the cams work best with a smaller carb. Figure these things out, then you can make an educated gess on what will help you out.

The 350x has some major potential. The key is to get the right combination of products, Small carbs and lightened flyweels dont work as well together, Big carbs and stock exhaust dosnet work well together.

One bike i have is a high flow, big camed motor, the bike FLYS. Has no power down low and revs out extremely well.

Another bike has a sealed off airbox choked up exhaust and low rpm cam. The thing is a tractor and donset rev out.

Both motors are ported to meet how the motor is built.

[Troll]

Unscrew the 350x from the spark plug. Then screw on a 250r..........Done :thumbsup:

[ADW3]

Unscrew the 350x from the spark plug. Then screw on a 250r..........Done :thumbsup:
OK, I've got the spark plug...

...almost there! :chuckle: :burnout:




Good one Troll! ;)

[225]

Unscrew the 350x from the spark plug. Then screw on a 250r..........Done :thumbsup:
You beat me to it.:lmao:

[250sx]

what all is involved in the 400ex/450r exhaust mod? Make a detailed post so I can do a new tech tip. :thumbsup:

[NOS_350X]

Dan, I was planning on doing this soon to another bike.

This time when i do it, i will take some pictures of EXACTLY what is needed to do it ok? maby in 2 weeks ill do it, Only one cut and weld is needed. Just removal of parts to take on and off.

[Duner]

I use PBI aluminum rear sprocket, and no problems yet, and they claim stronger than steel.


Thats because your not making enough power to chip them or round them down.

[All X's]

What kind of speed are you guys getting out of these set ups??

[NOS_350X]

What kind of speed are you guys getting out of these set ups??


Depends on how high of gearing i want to run. Top speed is less about power and more about gearing. The motors being discussed should have plunty of power to get into the 70's or 80's with the right gearing.

[250sx]

FYI - you can overrev a 350x engine so be careful trying to wind it all the way out full throttle for a long long distance. There is no rev limiter unfortunately.

[Troll]

I thinks its a good way of seizing the cam bearings................. :cool:
The roller cam bearing conversion looks sweet............ :headbang:

[NOS_350X]

Dan, depends on how you build the motor, I have never floated a valve, AT oregon i was trying having such a flat long wide open area. The hole way down it i was WIDE open. No problems and on that bike i dont have stiff vlave springs.