750 Crankshaft is out of Phaze. Please verify. Pics attached.
- Thread starter The-Hoss!
- Start date
AL P
Moderator
just for good measure....line up 3 & 4, then rock the motor slightly back and fourth, and see if the straw in the #1cylinder goes down when rotating the crank slightly one direction then lineup 3 and 4 again, and rotate the motor in the opisite direction and see if the straw goes down again the same amount....sounds odd, but its kinda a double check/confirmation doing it the opisite way...
Reason I`m suggesting this, is because when the rod is at or VERY near TDC, there is a bit of movement you can perform, without much notice of the straw moving (which can mistakenly cause ya to think 3 and 4 are off)..I discovered this when I first got my vmax4 and was checking it..for a few, I was convinced it was out..but everyone kept saying that typically only happens to the 750`s..anyway, after alot more messing around with it, I finally concluded it was`nt out.....
Reason I`m suggesting this, is because when the rod is at or VERY near TDC, there is a bit of movement you can perform, without much notice of the straw moving (which can mistakenly cause ya to think 3 and 4 are off)..I discovered this when I first got my vmax4 and was checking it..for a few, I was convinced it was out..but everyone kept saying that typically only happens to the 750`s..anyway, after alot more messing around with it, I finally concluded it was`nt out.....
The-Hoss!
Member
Hey Al P
Just looking at my spare 750 crankshafts. Particularly at the timing marks on the gears.
I noticed that the gears have 2 sets of Timing indents on them (which appear to be factory markings)
For example; the small gear has one on the inside & on the backside but they are in different locations. Same as on the large gear.
Any ideas???? Have you come across this before?
Just looking at my spare 750 crankshafts. Particularly at the timing marks on the gears.
I noticed that the gears have 2 sets of Timing indents on them (which appear to be factory markings)
For example; the small gear has one on the inside & on the backside but they are in different locations. Same as on the large gear.
Any ideas???? Have you come across this before?
Big Bore 904
Member
The photo in your first post shows what appears to be a 180 degree configuration. Cylinders 1 and 3 are paired and 2 and 4 are paired. I've seen this before. Some set them up that way some set them up so 1 and 4 and togetheer and 2 and 3 are paired. If the gears aren't welded it's easy to set it back uo for 90 degree firing.
The-Hoss!
Member
Huh....you know I was So focused on the 3/4 cylinder, checking my crank phaze, that I didn't even pay attention to that. So essentially I could leave it as is, & look for a 180 Cdi box.....correct??
or is it easier said then done...???
Big Bore 904
Member
You can do that. You can also split the case and set the cranks back at 90. What CDI is on the sled now?
opsled
Well-known member
I would agree with this assessment as a possibility or probability. Before going further I would measure each piston's TDC with a dial indicator in comparison to a degree wheel attatched to the recoil cup or something simliar so you know exactly what the degree of difference is between the two halves. The straw test is a good quick way of assessing what might be happening but is not an exact method of measuring and close is not good enough with crank phaze..
opsled
Jabber800
New member
Thx! We just found more power in that 600 this week! It's hooked up to the Dyno and we do pulls on it every few days trying new things. Im hoping we can get the v max on it by fall and get some numbers from it. Where shooting to get a 140 + mph pass out of a v max next year. The ski doo's are running high 130's where going to have to do a lot of work to be competitive.