Hi all, new to the forum here, and looking for a little info.

I just bought a 1998 Polaris Scrambler 400. it has a rebuilt motor, new rear axle carrier, bearings, brake pads and rotors all the way around, new front control arms, steering column bushings, and throttle cable(s).

I paid $500 for it, and i think it was an ok deal. the two things wrong with it are: The chain broke and slapped the transmission case and broke it, something that i am finding is quite common. so it needs a new case half. the tranny works fine, and doesnt make any noise, so i think i will be ok putting a new case half on it. It also needs a new chain, and i might as well put on new sprockets while i am in there.

Also the steering column broke off just below the mounting plate for the bars. I welded it from the out side, and i am planning on drilling 4 holes around the shaft below and above the crack, then sliding a steel rod the same size as the hole in the center of the column in and filling in the holes with weld to hold in the rod. i figure that this will be WAY stronger than it was stock. please correct me if i am wrong, and i am a good welder, and know how to weld properly.

My other question is about the 4WD. i bought this machine from a friend, and i know the history of the machine. i used to borrow it on weekends and one time i was blasting from trail to trail on the paved road, and it suddenly pulled violently to the right, and put me in the ditch at about 45 mph, i fought it and managed to hold it straight while blistering through the shoulder and ditch. when i stopped and looked at it, i saw nothing wrong. the 4wd button was OFF, and it seemed fine when i drove off. My buddy said that it happened to him once two. Is it possible that the 4WD engaged on it with out the button being on?. if so how do i make it NEVER DO THAT AGAIN. i know i shouldnt be riding it on the street, but i am glad it happened there and not on a trail with lots of trees to hit.

Let me know what you guys think. if i got a good deal and if its worth fixxing, and aslo any thing you can tell me about my wild ride on the pavement. I do love this thing, and i can't believe how easily it will hang the front wheels, i already pissed off the mail man when i passed him with it last summer going about 30 in a wheelie. lol Thanks for any input with my issues and machine....

 

Is it concentric drive? If it kicked in at high speeds then it is most likely either a warped driveshaft and if it is concentric it could be the prop shaft twisted or warped out of index. If they are warped they can cause a vibration (you most likely will not feel it) and the vibration will cause a magnetic field to be created in the
Hub(s) and cause it to slam in. I bet the AWD works fine otherwise and it doesn't do it unlesss oyu are at higher speeds. If so I'd bet that will fix it. It happened to me also. It was hard after that to get the nerve to get it to the 50+ range without 2nd guessing. When it happeed to me it nearly threw me a very high bridge with a very rocky, shallow river below. I nearly puked once i got slowed down and caught my breath

 

ii dont know what it has for engagement, but i do know that the front drive shaft from the tranny to the front diff has a little bend in it, and its not that bad but you can see and feel it.

 

$500 is a great deal! especially if you know the machines history.

but it sounds like you need to change the front hub fluid. if it is low or contaminated, it will make the 4x4 not work properly.

i think rick at ritter cycle racing will reweld that case half for you. it will cost way less than buying a new case half. you might give him a call.

X

 

On your steering post I would look on Ebay for a replacement one.Just to be safe.

 

the new case half is only $207 for a new on from polaris, and i can change it myself. i might send out the old one to have it welded later to have a spare on hand.

 

Look on ebay for a complete tranny.You may find one for a little more than the case.Then get the case welded.

 

if your prop shat that runs from the tranny to the front gear box is bent thats what most likley caused your hub to engage at high speeds. changed the prop shaft or it will do it to you again ncriderforks was on the right track.

 

there are little spings that hold the rollers on the cam inside the front hub. if they get weak it can cause the rollers to fly to the outside this causes the hub to engage. It can also happen if the front hubs are two tight. and dirty oil doesn't help either. in cause you didn't know an electro magnet is suppused to pull them to the outside when you push the button.