1973 643 hydraulic drive questions

[1sawandblackbetty]

Hey Ron I finally get to ask my Yamaha questions I hope you can answer. I have an ew 643b and out of all my sleds it's the best runner I got up until my current problem. I've never had really a problem with the fluid drive except it got hot on the trail one day and I figured out I needed a new radiator cap for the transmission system and all was good. I use it all the time for trapping up here in Hayward. The oil injection has always worked LOL now I'm going to take a second look at it after reading your post. Cuz I've had this sled for probably 15 years now and it's always ran great except for a hiccup at idle after I changed the points but never changed the condensers( don't aske why). It was a 1 owner sled I got out of cable with the original owners manual and all the notes from the Yamaha dealer in it. I figured out the pick up at the end of last winter changing the condensers the two ignition coils were barely connected and the wire was just vibrating back and forth but it still ran good so I changed condensers and lost the flywheel in that and the process and I think I soldered it bad so now I have no spark so I was hoping I could just change it to electronic ignition that would be awesome put new condensers in the end of last winter and never started it cuz I couldnt find the flywheel nut. condenser and I would like to change it to electronic ignition. This is probably my favorite vintage sled so far cuz it always starts and runs perfect and my daughter's love driving it . and One year when the rest of my machines were down I drove it all winter trapping and it was awesome up here in northern Wisconsin. So I got an 80 540 XLV and a 87 540 2 up, can I use ignitions from one of those and how do I change it I'm not sure what exactly all I need to change any help would be appreciated , I'm half ski Doo collector also and love LOVE my rotary valve torque monsters. my daily driver is now the on the 2nd of the same sled from 99 cuz it just rips so damn hard.( I wish I could find another one too so black Betty doesn't get all the miles ). So the real problem is I cannot find a seat cover for this damn ew643b. I don't want to pay a fortune either and I do have lots to trade as I'm a prof. Wood carver/log home builder from AK. A place in Rice lake wanted to charge me like 7 to $900 to make one, any chance there is a NOS one laying around for me anywhere!?!! cuz they don't exist my friend bought one once for his gp433 on ebay and it was for my sled and cut it up to fit his but this was before I owned mine and I was sick to my stomach after I bought mine when he told me that!! Lol Scott was a HUGE Yamaha collector, but he passed away last year. Sorry for the long post but I've been putting of doing research on this sled and saw your post so had to join and sitting in the hot tub this morning at -10 f I finally got the time! I'm up in Hayward if u wanna come up and ride!

 

[RON HYDRAULIC YAM]

Sorry , hadn't checked here lately ..
My brother soldered computers in the 80's but i never asked him how.
.
I have a number of "spare" engines if need some parts that are not local avail. but it might be spring unless
there could be one i pulled apart in the 90's..
I paid $1,000 Cdn for my 73 EW643 including a NOS seat cover for a 72 he got by accident ....He had
spent possibly 500 having the seat cover made )in 2005) for the 73 .. really nice job , even the lower pocket had
the zipper installed ...
Not aware of anyone converting them to electronic .. i tried using cardboard between each point set
so i could watch them open with a meter , one at a time ...Put it back together and forgot to pull the paper out. Pulled
the plate off and pulled the paper ... opps
...
I will try and watch here for any requests ... there were some good websites for Yam parts catalogs but the old
ones are getting harder to find for comparing part numbers .. The 643's are easy to see on the shelf with
the little recoil.
Of the fluid drives i brought home most are 433's
Ron