Indy (Fuji) 340 Fan, What Top RPM???

[Mtn-Track]

I'm trying to get the clutching dialed in and need to know what the spec top-end RPM is on the Fuji 340. Right now, it engages about 5000 and tops out at 7100. This is the result of using the Polaris jetting & clutching guide, riding at 9500ft elevation with a predator 1.25 x 121 track. It feels like it has more power/RPM available but I don't want it to explode. What are your thoughts?

Thanks for any help on this.

 

[Mtn-Track]

Anyone?
What about the newer 440 and 550 fan-cooled and the top end RPM on them?

 

[volcano buster]

It appears the fan cooled motors were only designed to top out at 6500 +-200 rpms. This went for the 250,340,440,488's as well.

Not sure which year you are dealing with, but my book shows for a 1993:

9,000-12,000'
Shift weight: 10M White or 10M Red
Clutch spring: Blue or Gold
Driven helix: 36.5° B-2
Chaincase gearing: 16:39

I don't have a tach on my Indy Lite so I don't know where it engages at, but 5,000 sounds aweful high if it is supposed to tach out at 6,500.

 

[Mtn-Track]

Thanks for the reply!

I'm working on a 2002 with the optional factory tach on it. I believe that the 2000-on versions had a higher RPM rating than the older one's. I've also been told that a newer 550 fan is supposed to spool up to the 7800-8200 (+/-200) range and engage at 5000.....

I'm using the Polaris clutch chart for this sled and currently have the blue spring and 10MW weights in it that's giving me the RPM that I listed. The next step would be to put the lighter 10MR weights in it but I want to check the top RPM limits before I do.

 

[indydan]

It appears the fan cooled motors were only designed to top out at 6500 +-200 rpms. This went for the 250,340,440,488's as well.

Not sure which year you are dealing with, but my book shows for a 1993:

9,000-12,000'
Shift weight: 10M White or 10M Red
Clutch spring: Blue or Gold
Driven helix: 36.5° B-2
Chaincase gearing: 16:39

I don't have a tach on my Indy Lite so I don't know where it engages at, but 5,000 sounds aweful high if it is supposed to tach out at 6,500.

Yep - designed to top out at 6500 +-200 rpms. This went for the 250,340,440,488's as well.

 

[Mtn-Track]

It would appear that the OEM clutch chart settings are letting this sled over-rev. It's still running a little rich, so I'll lean it out some more than start dialing in the clutch again. Installing the 10MR weights at this point may blow the engine...

So much for the 'conservative' clutch chart!