250R framed Polaris build

[Grande Huevos]

Ok guys now I know people have done the 250r lower end equiped with the polaris 400 topend but what im wanting to do is a little different. My friend has this huge heavy polaris 400 scrambler, and he loves the fact its automatic and its pretty quick with the mods hes done, but he hates how heavy it is and how it lacks good suspension. So we got to talking and were thinking about taking a decently set up 250R cross country style and puting the polaris complete motor in it. I think it would be pretty cool and would probally scream pretty good as well, but im afraid that it will be to big for the R's frame and the pipe might have to become out of frame also. This will deffinatly require some work and fabrication but I think if it can be done it will be pretty sweet. As of right now this is all still just a thought and i wanted to see if my fellow R riders have any advice or experience with somthing like this. Let me know what you guys think.

[BCTRX]

Hot Seat Perfotmance used to do a conversion simular to what you are thinking. They would take a Scrambler Chassis, remove the front end and add an A-Arm front end and stripped down back half. Don't know if there is anything like that still around, but they were fairly quick back in the mid 90s when Polaris was selling tons of Scrambler 400s. I had a few Scramblers years ago and HSP and Rath could coax some fairly good power out of those motors. Hot Seat Performance is now called Speedwerx.

[Grande Huevos]

Originally posted by BCTRX
Hot Seat Perfotmance used to do a conversion simular to what you are thinking. They would take a Scrambler Chassis, remove the front end and add an A-Arm front end and stripped down back half. Don't know if there is anything like that still around, but they were fairly quick back in the mid 90s when Polaris was selling tons of Scrambler 400s. I had a few Scramblers years ago and HSP and Rath could coax some fairly good power out of those motors. Hot Seat Performance is now called Speedwerx.
yeah that was another thought for us was to hack up a 250r frame and try to use the front end a arms and shocks and try to upgrade the rear shock of the polaris and get some smaller lighter rear wheels. Really anything to shed weight and make if handle/perform better. You can def make some power with those 400 motors too. They make a kit that produces like 76 hp it comes with big bore ported cylinder pipe carb and im not sure what els they might be all. The motor we have has different carb fmf pipe and its punched out like 60 over, also has clutch up grade so it gets up and goes pretty good.

[C-LEIGH RACING]

I think it was in the late 90s a team used the 400 Polaris at our TT events.

Was modded to the hilt with a arm front end & best I can remember, it did right well.
I think it finished like 4th place in the main event, dont remember the class though.

When you looked at it real close, it didnt look like there was a part on it had not been touched, modding every where.
When I first seen it coming down the drive, I thought it was a 250R, until he stopped & didnt pull the clutch lever.
Had extra tire stacked up on both nurf bars, with his left hand holding the left stack, so I'm thinking how is he going to pull the clutch.
It really did look good & if I remember right it was purple & had 250R plastic on it.

Hey you know what, as many of the 450Rs as it is sitting around with blown up engines & no where to get an engine, might be some cheap 450 frames out there to chop up rather than using the 250R frame.
Neil

[250Renvy]

Does the polaris use an expansion chamber?

[C-LEIGH RACING]

Originally posted by 250Renvy
Does the polaris use an expansion chamber?

Oh yes, just like any other 2stroke.
Neil

[turdboy]

A few years back here in MN a guy used to race a pimped out polaris 400. The frame was aftermarket and was full 250R geometry. The motor had like 80 something HP and he would dominate on the sandy tracks because he never had to shift and was always on the power. I think HPD did all of the work. They were or still are very big into the polaris 400 motors. Even lining up next to him on holeshots was weird because he would just sit there and idle, then pin it and he was gone.

[fastrnrik]

I had one of those Polaris 400 Sport's several years ago and with some fairly simple mods and clutch tuning, it was nasty. We considered the same project (250R conversion) for flat track & TT, but it was more work than we wanted to do, so we never did it.

There was one of those HPD hybrids for sale on here awhile back. It was set up for MX.

There used to be company in AZ that specialized in the 400's. Also AAEN was big into them at one time too.

[turdboy]

found a pic of the guy who used to race locally here in MN. The thing was sweet.

[fastrnrik]

Here's a link to an old thread. Lots of pictures too

http://www.exriders.com/vbb/showthread.php?s=&threadid=302559&highlight=polaris

[BCTRX]

I stand corrected on thinking it was Hotseat that built those race 400s. It was HPD that built those Quads. Good digging guys. Man that would be one fun ride!

[Grande Huevos]

Those things look better then I imagined!! that first one black with peps is sick!! Thanks so much for everybody that has chimed in and for the pictures. Thats a big help not to mention and boost of encouragment seeing so many that have already been done. It might be a little bit but I will definintly keep everyone posted with our progress as it goes! Thanks again my fellow R riders

[troybilt]

I forgot about those Polaris 400 hybrids. They were sweet, I'd love to build one!! I think you should definitely do it. I know you can get 450r rollers for 1000 or less... like Neil said. I have some articles on those that DW did several years back. I know they ran hard.

[Grande Huevos]

Originally posted by troybilt
I forgot about those Polaris 400 hybrids. They were sweet, I'd love to build one!! I think you should definitely do it. I know you can get 450r rollers for 1000 or less... like Neil said. I have some articles on those that DW did several years back. I know they ran hard.
Yeah i wouldnt mind using a 450 either i just figured a 250r would be cheaper, maybe not? But in order to get the chain on the other side would it be as easy as to just flip the axle around and basically flip everything to the other side? Not sure if you can do that i really havnt looked into it yet. If so I dont think thast it would be to hard of a project to do, and would turn out to be a fun trail bike!

[rk88r]

The ds 450's and old atc's have the chain on the other side.