I cut away what I didn't need of the atv, so it is just the swingarm, cvt, fnr, coilover damper, and supporting framework. I built a box around the oil pan from 1x6 decking board cutoffs and jigged up the engine and cvt on a sheet of plywood, then measured everything. The ring gear is within 1/2" of the FNR case but it will work. Crank center to the edge of the secondary pulley is only 5.250". The fnr tucks up against the block behind the fuel control. , I have about 3/8" clearance between the FNR case and the ring gear so it will work. I knew it would be tight. I will isolate the engine but use torque links to prevent closing this critical gap. I also had to cut the starter mount plate for clearance and removed some excess weight in the process. I may use the dodge mounts I have laying around.
I picked up a new Catepillar fuel filter / water separator off Ebay for $13. It is a very nice piece with a glass bowl and can use standard Fram filters.http://www.Guardiancouplings.com
is machining one of their forged stub shafts to accept the taper I need. I cut the old crank end off to mail to them today, along with the vw stub shaft to make a stub to accept the belt drive pulley through a QD bushing, SDS size. Unfortunately, I cannot publish their drawings, but I will provide drawing numbers so anyone interested in having them produce similar or indetical components, could start with those drawings.
I’ve torn down the fnr box to send the output shaft as a pattern for a new shaft that will accept a QD bushing and support bearing, moving the drive pulley to the right in order to center the rear wheel behind the cvt/engine assembly. The output shaft necks down to .985” at the bearings (standard 6305). I’m going to look for a larger inner race bearing and seal to fit a larger shaft, then decide who will be making it for me.
I'm using bicycle speedos to determine cvt gearing. The speedos are battery powered and come on by themselves once the magnet passes the pickup sensor. I'll epoxy the magnets the the pulleys, then calibrate the speedos to the same wheel diameter. When the speedos read the same speed, I've achieved 1:1.
I discussed my build specs with EPI Tech Support (http://www.epiperformance.com
). They make various tuning components for the Polaris cvt. All they offered as far as tuning is to reach max rpm by 20 mph for best acceleration.
I've added curb weight, which delays upshift and increases slippage and stall speed.
I've reduced the gearing numerically, which delays upshift and increases slippage and stall speed.
I'll need to increase belt grip to offset the two items above by increasing secondary spring tension, which also increases stall speed.
Spring tension would be adequate otherwise, considering the maximum torque value of the old atv engine is approximately the same.
Adding sufficient flyweight will bring the max rpm when fully loaded down to 3600 rpm and reduce the stall speed. I currently have 55 gram flyweights. Up to 86 gram weights are available, but sets are $120.
I'll probably weld material onto mine then grind to get the weights even on a precision scale.
I dropped off the flywheel at the machine shop a couple weeks ago to be lightened. All I need is the ring gear and stub shaft mounting. There are balancing holes on the back, so it is externally balanced. It weighed 27.220 lbs before machining.
I jigged up the engine and cvt yesterday on a sheet of plywood layed over a hand truck, then a made a box from 1x6 deck board scraps to support the engine at the pan rail on the board, then nailed blocks of wood around the box to keep it in position. With the crank center line 5.250" from the edge of the secondary pulley.