Super Jet full 61x vs 61x/62t low-mid range power

OtherDonnieGuy

OtherDonnieGuy

Location
Illinois
So I just recently put a stock 61x/61x motor (pulled from a vxr pro) into my '91 square nose hull in place of the stock 650. I swapped ebox over too so it does have 701 cdi. Kept the 650 carb but changed all the internals over to stock 701 specs. Everything else is the same from the 650. My buddy has a bone stock '06 round nose and it has quite a bit more power everywhere. Is a dual carb 61x/62t gonna have more low end punch than a full 61x with stock single carb? I talked to a guy and he said changing out the 650 exhaust tube for a 701 tube will make a difference in low end. Is this true on a stock motor? also looks like yamaha used a different (larger?)exit nozzle on the pumps starting in 93? Pump and prop look to be in good shape to the eye but I have no idea what the pitch is. I want to keep the motor stock for reliability reason, what do I need to do to make this thing hit harder off the bottom end like my buddies round nose? ...I will eventually be getting a b-pipe but thats down the road.

Also Anyone have a good prop recommendation for freeride with a stock 61x??
 
mdelima353

mdelima353

Location
CA 94582
High compression head w/ 35cc domes to get the compression around 185psi, have your flywheel lightened, and a pipe will make a huge difference over stock..
 
S

Schmidty721

someone turf my rails
Location
WI
Don't waste your money on a lightened stock flywheel. You won't notice a difference.

As mentioned above, head, pipe and matched prop/pump setup for your engine is the best band for $$
 
kevbo

kevbo

Location
dfw
SomeDonnieDude said:
Is dual 38mm carbs and 62t cases gonna give me any more low end power vs my stock 61x setup?
Click to expand...

Not by itself. 90% of the thrust comes from the pipe, porting, and pump combo. Big carbs, high compression, and light flywheels help with throttle response. Start with a pipe and low pitched impeller, those items will do the most good.
 
Idok

Idok

F1pro
Location
Nations oldest muthaF+++kin city
a full 61x makes great low end power with a few simple mods......

46/48 carb, 180 psi, bore the intake/exhaust to 48 and match the ports to the gasket, static advance the timing 2mm



the timing mod is what pulls it all together
 
OtherDonnieGuy

OtherDonnieGuy

Location
Illinois
Are you saying a 61x/62t motor uses a lighter flywheel than full 61x????? I don't want to know what mods will increase power, but is my stock nozzle and stock 650 waterbox/exhaust tube holding me back?
 
W

waxhead

wannabe backflipper
Location
gold coast
The 62t cases have much more potential power when you start really going crazy with the mods. At this stage its better value for money to put a pipe and a head on it
 
kevbo

kevbo

Location
dfw
SomeDonnieDude said:
Are you saying a 61x/62t motor uses a lighter flywheel than full 61x????? I don't want to know what mods will increase power, but is my stock nozzle and stock 650 waterbox/exhaust tube holding me back?
Click to expand...

A 6M6 and 61X flywheel is smaller and lighter than 62T. Your 650 nozzle is as big or bigger than any 701 nozzle and your 650 muffler/outlet tube was also used with 701s and not a performance factor.
 
OtherDonnieGuy

OtherDonnieGuy

Location
Illinois
kevbo said:
A 6M6 and 61X flywheel is smaller and lighter than 62T. Your 650 nozzle is as big or bigger than any 701 nozzle and your 650 muffler/outlet tube was also used with 701s and not a performance factor.
Click to expand...

so im guessing i just need to repitch/replace my prop? and maybe play with my carb make sure its dialed in?
 
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