After a month of riding in our no snow low snow deep wet powder winter, this is how Dan 2023 300sx has been working out.
300 with a used 2019 or there about ARO 120 kit.
In Sept when the conversion was started the thought was be thorough, lots of time its snows, so lets address all the issues.
1. rolling resistance on the ARO kit was horrible, you had to drag it around the shop, would not roll. Disassembled the kit, narrowed all the wheels, replaced the fat little upper idlers with narrow aluminum wheels we machined a few years back, respaced the rear tall idlers to run in the center of the area between the lugs, spaced the drivers to minimize drivers rubbing on the rubber drive lugs, put the driveshaft and drivers in the lathe and cut the faces of drivers to run true, some new bearings, bolted it back together with bending and spacers so the suspension would run fairly true and minimize hyfax rubbing. And when back together you could push it around the shop like you would expect with the track rolling and quiet.
2. second item was mounting the ARO kit as close to the bike frame as was reasonable. To get that done we machined a lot of unnecessary aluminum off the cast aluminum mounting plate. Not hard to figure, just shove this piece back into the ARO frame and start grinding/machining/hacksawing where there is interference , when done you will have to make a shorter adjuster bolt, and drill or elongate the holes for bolts that clamp this thing together. When done the whole kit moves forward and you can run two links shorter chain on the bike to kit chain. AND you can run without the power robbing plastic block that comes in ARO/Riot kits. This is covered in quite a few posts the last 3 or 4 years. And I shortened the shocks to be like an S kit. So what does this get you, a more tucked under the bike track system. Riding a riot kit modified this way for the last 3 years I forget about it, until I trade with somebody with a KTM /riot kit as per the other day 2024 sx 120 and not 3" track, ok bad setup needs some help. I will say the beta 250 and 2023 300sx both seem to benefit even more than the 43 strokes with this improved riding stance. Never been on a snowbike that jumps up on top of the snow leaving as shallow a track in the snow as the 300 up on the pipe.
3. Over the years we felt that all the heat exchangers we had built were unnecessarily big, Dan had made up several u shaped coolers of 1" aluminum pipe and we installed one on his 300 and one on a 250 beta in our riding group. So far works great, minimal expense, minimal weight, and so far 150 degrees consistent, both bike appear to thrive on that temp, but maybe somebody knows better.
4. And heated bars, and truck tarp covering all around, and several tries and changes on plumbing, bar risers, air box stock so far on the 300.
And its quiet, and its now annoying to ride beside the new 450 Ktm in the group and I guess it would be 4 KTM's 450 in the group. Fun, jumps up on top of the snow, everyone wants to ride and then won't give it back.
5. Should add, on most of our 4 stroke kits we have run somewhere around 13-13.5"track run out.
On the 300 sx its takes about 15" of track run out to feel good and it pulls it no problem, so far. With the lower rev'ing two stroke, got to gear it up to create track speed.
So for sure one bigbore 450 with ARO kit will go down the road, my 500exc is headed to be somebodies next dirt bike, two words smooth and quiet.
I will try and post pictures of some of these parts etc when I get back to my office computer.
First two pictures are of he 1" aluminum pipe heat exchangers we are running and dan making them on his pipe bending jig. Before we bent them to shape the pipe was put in the lathe and we cut shallow rings in each end of the pipe so rubber hose seals up, probably not necessary. We found adel clamps worked as well for mounting, I'll try and find pictures of them installed. Work sheet showing how much we cut off aluminum mounting plate. shows adjuster when mounted, this is actually on a riot. 5th picture is cooler installed, 6th picture is relief machined to minimize chain slap hitting on left side aluminum mounting bracket. 7the picture heat exchanger tube from the top side.
