Yamaha Nutz
New member
I have had this idea bouncing around in my head for the last few years, it is one of those things i have been thinking about at least once a week ...
Well the time has come to start the build. while i have been designing and porting the engine over the last month with the weather getting better and things in its slow time in the shop it was time to start on the chassis ....which i bought last fall as a complete sled with a scored piston from the previous owner not doing the overhaul right .....more on that later ......the sled was not mint looking nor original but chassis was strait tunnel was mint .....too mint. i realized that some where n the life of the sled it was rebuilt the belly pan is mint and the tunnel too because they where replaced and no serial numbers on tunnel plus it was pop riveted together not buck riveted which made for a quick disassemble , i will post pics later as to what we are staring with and the process of the build ..... along with all the other projects i have going on i hope to have this one to the grass by fall and ready to go for the ice then
Well the time has come to start the build. while i have been designing and porting the engine over the last month with the weather getting better and things in its slow time in the shop it was time to start on the chassis ....which i bought last fall as a complete sled with a scored piston from the previous owner not doing the overhaul right .....more on that later ......the sled was not mint looking nor original but chassis was strait tunnel was mint .....too mint. i realized that some where n the life of the sled it was rebuilt the belly pan is mint and the tunnel too because they where replaced and no serial numbers on tunnel plus it was pop riveted together not buck riveted which made for a quick disassemble , i will post pics later as to what we are staring with and the process of the build ..... along with all the other projects i have going on i hope to have this one to the grass by fall and ready to go for the ice then
shaggyzr2
Active member
Cool! 
yamahamark
Member
Sound like a fun project.
opsled
Active member
Mike's work is impeccable. This one will be a good one to follow.
opsled
opsled
Yamaha Nutz
New member
Well here are some pics. Got the new chain case mounted to roll back the drive axle which is the next step to get the speedo side all squared up now
guigui
New member
Cant wait to see the final result.
You do a drop and roll of the chaincase?
What are the expected specs in terms of engine, track, gearing etc...
You do a drop and roll of the chaincase?
What are the expected specs in terms of engine, track, gearing etc...
Yamaha Nutz
New member
New drive axle all machined up and fitted just have to decide on which caliper I use and get that mounted then I have to get a key way machined for the brake disc which is something I can't do in the shop but the biggest part of the drive line is done ....
Throttle Junkie35
New member
Sweet!!
Yamaha Nutz
New member
yes axle was dropped and rolled for a little extra clearance track will be a 121 speed track with to be decided amount of studs gearing will have to be figured once motor package is finalized , but i have a good idea where to start rear skid i am planning on a wahl skid ....motor will be a phazer engine with a new radical port map i designed and had looked over by another master 2 stroke wizard ...and we are on the same page that lets give it a go . carbs will either be 40 mm flats or 44mm rounds v force reeds with twin pipes motor will spin in the 9500-10,000 rpm range with updated ignition i hate to speculate hp numbers but, only time will tell
toydoc
Member
I'd find some used aftermarket pipes off a ZRT 600. Like PSI or Black Magic. Use 2 and fit them to the phazer. That will hit your target rpm and make good hp and cheap
Yamaha Nutz
New member
thanks for the tip ...but i will be using a set built for the motor not that i wound not mind saving the money but to go through all the work of refitting the pipes i would be better off, i think, with a set built to how i want them to sit and exit the chassis
Yamaha Nutz
New member
Tunnel mated back together with a few rivets to get the of the holes drilled and to get the stance set 
Yamaha Nutz
New member
little update been a little busy so not much progress on the sled but i do have the drive line and brake system all finished up and front suspension set for the stance i am looking for hope to get some more done on it this weekend i will post pics later .....cylinders and heads are just about done and custom flanges for the exhaust are all machined up and i will be picking up the ball cups for them this week then i will get the mock up motor in the sled to start fitting the pipes. carbs have been decided on with 38mm tmx mikunis taper bored to 42 things should be coming along well with in the next month
guigui
New member
Could you give me more details about your drop and roll, there is no kit for those chassis, I want to do it on my exciter but wonder a bit on hotw to keep the cross shaft properly aligned
I strongly recomend using a slotted or wave brake disc since you going to run it inside the tunnel.
You will get much better and consistent brake performance right from the start when you get on the brakes.
Yamaha Nutz
New member
no room for a wave disk due to clearance from the track to disk rotor will be cross drilled for cooling but since it is a drag sled brakes will not be used that hard .....
Yamaha Nutz
New member
Little more progress pics dummy motor mocked up to start to get a idea for pipe fitment which looks will take some time. Hopefully the finished tuned length will allow me to get the pipes to exit where I want them too
Yamaha Nutz
New member
well for rolling of a chain case or drive axle there are a few ways to go about doing it one way is to use the stock chain case and dropping the jack shaft down lower either with new mounts or running it through the bulkhead and using the same chain case , or making a chain case cover and using the bulkhead as your inner chain case, or lastly using a different chain case with a longer center to center bearing spacing so for yamaha center to center wise it would be phazer to vmax/srx/ex570 to old school EX440 from shortest to longest i never did check the pogo vmax 500/600 but i think they are longer yet same goes for the proaction sleds but i was looking for light weight and the last 2 are quite heavy and would not really work with what i wanted to do i ended up using the old school Ex 440 case and spacing it out to give me the same witch to keep the drivers centered and jack shaft in the same location as far as keeping things aligned it involves a little bit of time and math ...
since i was leaving the jack shaft in the stock position to keep from re-figuring my belt center to center it was just a matter of deciding on what my drop and roll would be which i still may change a little yet but right now i am about 3/16'' drop and about 3.5'' back i do not have my papers in front of me for the exact measurements .....but i was looking for a little more clearance for studs and the 9 tooth drivers but i mainly wanted to stretch it back to lay the sled our more to control ski lift at launch and to be able to keep more track on the ground for traction without lift so just going to a 121 from a 116'' gives me about 2-3 more inches on the ground and now rolling it back gives me about another 3'' basically giving the sled a stance of having a 136'' track on it but only having to turn the weight of a 121 but with a speed track and lesser amount of studs give me about the same weight as a 116'' track loaded with studs as the 116'' track and 121 speed track weight wise are just about the same with out studs, it is a win win and helps aide in getting the weight down on the sled as i want it as light as possible i am really hoping to bring it in at or under 320 lbs so far there has been a bunch removed but i now have to start assembly and see what has to stay and what can go
keeping things square is not as hard as you would think but you also have to make sure things are square to start which most are close but not perfect. So the fisrt thing to do is square up everything (stock drive axle, jack shaft, and case then take your measurements once that is done take your new center to center and start doing the math as to where the new points will be for the drive axle.....double and triple check everything, drill and cut the new holes then mock everything up and double check that everything is square in the chassis and make adjustments as needed for me on this bulkhead i was more than half way through be for i saw that the bulkhead was junk ....i have a few spares so i have no problem with messing this one up which i didn't but it will make thinks muck easier to just mark and drill hole on the bulkhead i will use
Yamaha Nutz
New member
Slow things are getting mocked up ..... Got the new seat foam all finished up now
To work on getting a skid
To work on getting a skid