D-Roc
I forgot!
- Location
- Dirty River Rider
too bad one can't run ther stock electronics with msd enhancer as a total loss using that flywheel. those flywheels make the engine feel so snappy. Damn Charging system!! :headbang:
Lightening My Stock Flywheel - Tips
- Thread starter 93SJ760
- Start date
93SJ760
X-H
- Location
- Timmins, Ontario
Thanks for the link to the other post Robertg. I didn't realize the 61X was lighter. How about the 650 (6m6) electronics. Does anyone know if they're compatible and what the weight is? Also, anybody ever get the exact weight of a RAD or similar charging flywheel? I'd be interested in seeing how much gain you get be going to an aluminum flywheel.
Thanks.
Thanks.
The 6M6 stator is the same as the 61X stator. The voltage regulator, starter, coil, and relay are identical between all years SJ's.
The CDI is specific to the 650 (6M6). It will run a 61x motor (or 62T), but the Rev limiter is lower.
The CDI is specific to the 650 (6M6). It will run a 61x motor (or 62T), but the Rev limiter is lower.
93SJ760
X-H
- Location
- Timmins, Ontario
6M6 VS 61x flywheel
So does this mean that the flywheel weight of the 61x = 6m6?
So does this mean that the flywheel weight of the 61x = 6m6?
93SJ760
X-H
- Location
- Timmins, Ontario
Lightened Flywheel
So does anybody know how much the fly wheel's are turned down? Or can someone confirm that they're just taken down on the front face? From that and the weights I was given I could just figure out how far to go. Just want to make sure it's in the right area and that it's an even amount and not tapered or anything.
Also, anybody know the weight of a Rad charging flywheel? Curious to know if lightening a stocker is equivalent?
From the info above, if I own a 6M6 charging system as well as a 62T I would be better off shaving down the flywheel from the 6M6 as it's lighter to begin with? Or will I be losing out on output or performance from the 62t flywheel and stator?
Anybody know?
Tyler
So does anybody know how much the fly wheel's are turned down? Or can someone confirm that they're just taken down on the front face? From that and the weights I was given I could just figure out how far to go. Just want to make sure it's in the right area and that it's an even amount and not tapered or anything.
Also, anybody know the weight of a Rad charging flywheel? Curious to know if lightening a stocker is equivalent?
From the info above, if I own a 6M6 charging system as well as a 62T I would be better off shaving down the flywheel from the 6M6 as it's lighter to begin with? Or will I be losing out on output or performance from the 62t flywheel and stator?
Anybody know?
Tyler
WAB
salty nuts
- Location
- coastal GA
I don't think you would lose any performance with the 61x/6m6 flywheel vs the 62t one. The 6m6 & 61x have larger D shaped cutouts on the face of the flywheel and are slightly lighter to begin with as stated already.
I believe Group K removes most of the material from the outside of the flywheel (next to the ring gear) when they lighten one. Less rotating mass on the outside of the wheel.
You can email Group K and Protec & they can tell you approx how much weight they take off and where.
Edit: here's some info I had saved. I think Jetski Solutions was the orig poster of this info.
Yamaha CDi flywheel stator info
6M6 box (650 models) 6500-6600 limiter works on 61x system
61x box (701 94/95) 7050-7150 limiter works on 650s but not 62T systems
62T box (701 96+) 7050-7150 limiter works only on 62T systems
SJ Master: I have extensively tested the 61X and 62T on our engine simulation machine. If a 61X and 62T CDI are operated on the same stator, the outputs (high voltage) at any given rpm is about the same. The same cannot be said if the CDIs are used with thier respective stators. The 62T has an increased output up to around 2500, then about the same as the 61X up to the rev limit, which varies slightly. I have unpotted a few of these, and the general circuit trace layout appears to be about the same, but the component values and tolerances seem to vary regardless of generation.
I believe the increased output of the 62T is mostly due to the beefed up charge coil and stronger magnets, and not any difference in CDI design.
You can convert any motor to either system, as long as matching flywheels are used, as the 61X is smaller in diameter.
It is interesting to note (for good starting performance) that the 62T setup generates a nice health spark with a quick low torque hand spin of the flywheel (on the stator machine), in less than one revolution, and the 61X always requires a much more forceful spin to even get the first spark, which is visable less powerful on the calibrated spark gap (6mm), which usually occures in at least one revolution, sometimes more.
I believe Group K removes most of the material from the outside of the flywheel (next to the ring gear) when they lighten one. Less rotating mass on the outside of the wheel.
You can email Group K and Protec & they can tell you approx how much weight they take off and where.
Edit: here's some info I had saved. I think Jetski Solutions was the orig poster of this info.
Yamaha CDi flywheel stator info
6M6 box (650 models) 6500-6600 limiter works on 61x system
61x box (701 94/95) 7050-7150 limiter works on 650s but not 62T systems
62T box (701 96+) 7050-7150 limiter works only on 62T systems
SJ Master: I have extensively tested the 61X and 62T on our engine simulation machine. If a 61X and 62T CDI are operated on the same stator, the outputs (high voltage) at any given rpm is about the same. The same cannot be said if the CDIs are used with thier respective stators. The 62T has an increased output up to around 2500, then about the same as the 61X up to the rev limit, which varies slightly. I have unpotted a few of these, and the general circuit trace layout appears to be about the same, but the component values and tolerances seem to vary regardless of generation.
I believe the increased output of the 62T is mostly due to the beefed up charge coil and stronger magnets, and not any difference in CDI design.
You can convert any motor to either system, as long as matching flywheels are used, as the 61X is smaller in diameter.
It is interesting to note (for good starting performance) that the 62T setup generates a nice health spark with a quick low torque hand spin of the flywheel (on the stator machine), in less than one revolution, and the 61X always requires a much more forceful spin to even get the first spark, which is visable less powerful on the calibrated spark gap (6mm), which usually occures in at least one revolution, sometimes more.
Last edited:
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
93SJ760 said:
some shops remove it from the face, some remove material from the outer surface.
It just depends, the main thing is dont take too much, the wheel will eventually fracture if you remove too much or from the wrong area.
there was a thread a while back, maybe on pwctoday where Magoo had done some research on some fractured wheels, might be worth searching for.
there have also been alot of pictures posted of lightened flywheels before.
KR
www.krlines.com
- Location
- San Diego, California
Yeah, I would like to know about this too....
Mark44
Katie's Boss
- Location
- 100% one place
Measurements taken off of a lightened 61X fly wheel.
Diameter 4.990 Chamfer face .290 and side .178
These dimensions were taken off of my current flywheel after lightened.
No gains felt.
I know of no builders that balance the fly wheel, the equipment would be quite expensive for them.
Mark44
Diameter 4.990 Chamfer face .290 and side .178
These dimensions were taken off of my current flywheel after lightened.
No gains felt.
I know of no builders that balance the fly wheel, the equipment would be quite expensive for them.
Mark44
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
I felt it when I installed it.
but I also advanced my timing while it was off.
Combined its a noticeable difference.
its a $50 modification, do you really expect something that isnt a subtle difference?
but I also advanced my timing while it was off.
Combined its a noticeable difference.
its a $50 modification, do you really expect something that isnt a subtle difference?
Mark44
Katie's Boss
- Location
- 100% one place
o
I would have to say you just noticed your timing advance.
I get the same noticeable increase in HP and torque curve when I paint the fly wheel silver. LOL
Mark44
I would have to say you just noticed your timing advance.
I get the same noticeable increase in HP and torque curve when I paint the fly wheel silver. LOL
Mark44
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
so,
Do you think that a MSD total loss system would feel the same with 32 degrees of initial advance, but a 3.5 lb flywheel?
its the same as people saying they feel a difference in turning a High speed adjuster from 7/8 to 1 turn out.
or openeing a FPP headpipe screw from 1/4 turn, to 1/2 turn.
its all subjective, and its all different, no two boats are identical.
half a lb of weight is significant when its turning 4000-7000 RPMS.
Do you think that a MSD total loss system would feel the same with 32 degrees of initial advance, but a 3.5 lb flywheel?
its the same as people saying they feel a difference in turning a High speed adjuster from 7/8 to 1 turn out.
or openeing a FPP headpipe screw from 1/4 turn, to 1/2 turn.
its all subjective, and its all different, no two boats are identical.
half a lb of weight is significant when its turning 4000-7000 RPMS.
Mark44
Katie's Boss
- Location
- 100% one place
Yes MSD a significant change, lightened fly wheel no significant change.
Air fuel ratio yes can be significant change on very well tuned engines but first people need to spend more than 20 bucks on a meter to tune.
Factory pipe tuning screws I say definitely a noticeable change on a well tuned motor.
Mark44
Air fuel ratio yes can be significant change on very well tuned engines but first people need to spend more than 20 bucks on a meter to tune.
Factory pipe tuning screws I say definitely a noticeable change on a well tuned motor.
Mark44
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
you got the examples but missed the logic Mark.
Mark44
Katie's Boss
- Location
- 100% one place
I know the logic, just saying I can not notice a 1/2 lb with a lightened wheel and I don't think it is even a 1/2 lb and my tuning is dead on but I do understand what you are talking about.
I would lighten it if I was doing it my self but would save my 50 bucks for something better like beer.
Mark44
Last edited:
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
Most folks will say the total loss lightweight flywheel is the BIGGEST benefit and that coupled with the massive initial timing is what gives it the snap of a total loss setup.
Now, you cant lighten the stock flywheel THAT much, or advance the timing THAT much with stock parts.
but you can move in that direction for PENNIES on the dollar versus Total loss cost.
In my opinion, its one more cheap way to get more zip, with less $$, and retain stock electronics reliability.
Now, you cant lighten the stock flywheel THAT much, or advance the timing THAT much with stock parts.
but you can move in that direction for PENNIES on the dollar versus Total loss cost.
In my opinion, its one more cheap way to get more zip, with less $$, and retain stock electronics reliability.
Mouthfulloflake
ISJWTA member #2
- Location
- NW Arkansas
the last one I had cut was somewhere between .4 and .5 lbs taken off.
been in service for 2 years now, on a couple of different engines.
been in service for 2 years now, on a couple of different engines.