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View Full Version : Building MX 350X ,many questions ???



sandpuppi101
01-17-2007, 10:35 AM
Well I said last year that I was going to be coming down to Ohio and get some MX time in with you guys this year so I am rounding up stuff to get this project rolling! My foundation is gonna be a '85 350X motor and I decided to go with a '86 frame ,I want a little better built frame .. I have some nice tires ranging from Holeshots on 9 in wheels to 18x8 low pros to 20x8 meaning wheels! What am I getting into with this,Do I need a teather? Foot guard's ? Just need to know some logistics of what I need To race and as always hop up ideas are greatly appreciated ! I don't know if I can make a bunch of races down there but I would like to try it out plus they have a few tracks up in my neck of the woods!!

Mosh
01-17-2007, 11:02 AM
Not that I have much MX experience,But you will need a kill swicth for sure.It is a saftey rule.I would really look into some suspension set-ups for the track.A mild 350x engine will be fine for racing.I found that more track experience makes you faster than the baddest engine or bike.You will have to wear a helmet and nice boots,work boots over the ankle will be fine.Oh and a number plate.I Like to wear a chest protector to protect from rocks and roost and the occasional handle bar slap to the ribs.lol.Some of the faster guys out there are on mostly stock to mild modded machines.They just run alot of races and run well.The 18 inch tires would be my prefernce for most tracks and maybe a wider axle would suit you well also.

Kintore
01-17-2007, 12:15 PM
Get some progressives springs for sure, maybe a works rear shock or something of the like. Wider axle is always really nice, 18in tires for sure. Kill switch, good riding gear.

See ya soon!

350Xhilaration
01-17-2007, 12:16 PM
I'd have to say concentrate on the suspension more than anything else. A stock 350X (in my opinion) jumps like a brick. Take-offs aren't bad, but landing is horrible. (even when I don't crash).

I'd think a 2 stroke would be a better platform for an MXer, but if a 350X is what you want, then you could probably make a decent machine with some work in the right areas.

Other thing...get in some seat time and get in shape. (not sure what shape you're in now) MXing is tuff as heck from the few short laps I rode. I am convinced my wipeout last year was because my legs and arms were like rubber after several laps and I was winded to say the least.

Good luck!!

sandpuppi101
01-17-2007, 01:05 PM
Yeah ,I already did the 2 stroke thing,I had my R for years and fell in love with the thumpers ! Suspension is on the list,and the 18's will be on the list also.So I don't need any foot guards or anything,ahe ? I used to race back in the 80's in the 250 B class dirt bike and I know what your saying about being in shape,I still remember getting arm pump so bad it was all I could do to hold on!! I am getting excited for this project!!!

3leggeddog
01-17-2007, 08:24 PM
you wil need a tether for sure.heel guards are not required.the hot setp for a 350x imo.....


custom 10 inch front wheel,so you can run a 20-21 inch tire.the four strokes push bad in corners,the tourqe makes the front wheel light.if you lower the fornt of the bike,you lower your center of gravity, putting more weight up front,helping that front tire bite more.

a 18 inch turf saver is my choice for dry conditions,and a turf tamer for wet.

now if your seriuos,heres my suspionsion advice.swap that swinger out.a 250r swinger,or 400ex swinger will fit with minor mods.this gives you many more shock options,for less money.you can buy a nice r shock for a few hundred.now you'll be switching out the whole rearend.but nows the time for that +4 lonestar/durablue!!

up front a 250r front end is much needed.with progressive springs,your front will be tons better.

all depends how seriuos you wanna get,and how much time.dough your puttin into it.let me know if i can help with anything!

Derrick Adams
01-17-2007, 09:07 PM
I'm with 3legg on this one. Both of us have ran 350X's in MX with fair results but some careful planning will really help you out.

Here are a list of mods I would suggest after your comfortable on a stock bike. (TimSr will tell you a stock bike is competitive, which it is with practice BUT these mods will help anyone be faster)

Stage 1:

Durablue wheel spacers on rear to widen that stock axle
1 1/2" PVC spacers in front forks with fresh 10wt oil
Dunlop KT-151 front tire (22x7x11) to lower front ride height
Carlisle Turf Savers (18x9.5x8) to lower rear ride height
Remove airbox lid and spark arrestor from silencer/ add jet if needed
New front and rear brake pads/ chain & sprockets (if needed)


Stage 2:

250R swingarm and shock linkage assembly W/ aftermarket rear shock for your weight
+ 4 axle assembly
250R front forks and triples with Progressive springs
Aftermarket engine upgrades

The most important thing on a torquey 4 stroke is that you keep side traction to a minimum and the front tire down so you can turn fast. Tire selection is CRITICAL.

Not much to it really. With that basic set-up you should be very capable of staying with the pack, provided your comfortable on your bike at speed.

sandpuppi101
01-17-2007, 11:16 PM
Points well taken ,I guess it's gonna be a little bit of trial and error but I think I have a platform . Looks like I have alot of work ahead of me to get ready for this season!!!

dividebyzero
01-18-2007, 02:48 PM
I don't know if you already know this,but,the clutch cable routing will be different.The 86 frame won't have tabs on the frame like an 85 to hold the cable.Just thought i would mention it.;)

sandpuppi101
01-18-2007, 03:46 PM
Yeah I did know that but did'nt think about it either,thanks for the heads up on that,I know there is alot different with the 2 years in general... I am sure I will have other issues also,But...... I 'll get it figured out .Did you ever sell your 452,I saw it up at auction,Nice machine!!