How do you know when your lefty needs service?

wakeboardR2wheels said:

A few questions here, first how do you know when your lefty needs service/rebuilt, etc.? I have a 2005 Prophet 2000 with the Carbon Lefty Max 140 w/SPV and I have about 500 miles on it.

At 500 miles it is a judgement call. Cannondale says about every 40 riding hours, I generally say once a year is sufficient. That said, riding conditions are a huge part of the equation, the nastier, muddier or dustier your rides are, the more frequent you will want to think about it.

Second, does the lefty have oil inside? On a few occassions I've noticed what appears to be oil on the outside of the boot attracting dirt.

Yes it does, but it should not make a difference in plushness. Which boot, and where, top little breather hole boot, or lower ridged boot?

Third, my rebound adjustment still seems to make a difference in settings but it no longer clicks between settings - just very hard to turn with no click points.

This makes me think you ride in crappy conditions, as it is just ball bearings perched on top of springs inside little holes that make the clicks against the underside of the red cap.

Forth and last, can the (above) average guy rebuild the lefty? I've rebuilt Motorcross forks often and know my way around a toolbox quite well. Before I get in over my head I was just wondering if this is a project even worth undertaking or if special tools/equipment/parts are needed?

You will need some special tools, or time and creativity to get around that. Most shops will charge $25 to $35 to rebuild it, if they charge more, find out specifically why, as it is not that long a job. If you wish to do it, I can help you through it, but it may be easier to get it to a shop. I also offer the service at my shop, and many folks send them in, but I strongly encourage supporting you LBS, if they are competent with these forks, if not, contact me, and I'm glad to help. Good luck!

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wakeboardR2wheels said:

Hey, thanks for the quick reply!

Yeah, I've been known to ride in nasty muddy and if it's not muddy then it's dusty conditions.

500 miles at my pace is way past 40 hours! That's a good starting point I guess.

As far as the oil leaking, I'm not 100% sure, but I believe it was "toward the bottom/front" Whatever that means. I know with the MX stuff I've played with the seals are always the first to go due to mud/dirt and it causes the oil to leak out. Just wondering if my seal (if I even have one) is bad or needed replaced.

I didn't realize it was such a "cheap" rebuild. I have a LBS that I really like but they are not a cannondale dealer and he always gives me crap about my one legged fork... may have to ask the question anyways and see if it's something he can work on. My closest cannondale dealer is not to close and I don't have a good relationship (or bad - just none) with them. May have to give them a call as well. For 25-35 bucks I'd say it's well worth letting the pros do it. I'm still amazed how cheap bike shops are with their labor rates! Try pricing out fork seals/replacement on a MX bike...

Thanks again Mendon!

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wakeboardR2wheels said:

Thanks Dan, I hear ya there!

Hey OT question - what's LA CHEVRE mean to you?

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wadester said:

I just did the first basic service on a 1 yo 130 Max/TPC unit. all was basically cool - half of the filter holes were oilydirt clogged, but the filter itself was clean.

My real Q is - the grease on the leg was more like oil, and at first I thought there was crud in it but it turned out to be grease blobs. So, is this an internal damper leak or just the factory setup. I wiped&cycled&wiped til it was just as clean as I could make it - then regreased it. Damping works well, but I noted that rebound was one click from full.

Any checks to tell you if an internal seal is going????

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MendonCycleSmith said:

Was the grease just very light viscosity, or literally runny, and came pouring out when you opened the boot? If there was oil in enough quantity to make a run down the leg with the lower boots' zip tie off, you have a leak. Typically it's the so called Quad seal at the top of the fork's rebound assembly. It seals the rebound assembly shaft as it moves through the top cap of the inner leg. Need more info?

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Dan Gerous said:

I'd rather let a Cannondale authorized shop do the work if it was me. Most others won't know much about the Lefty (they'll probably say: Bearings in a fork? What the?) and if they don't, you're probably better off doing it yourself... and a lot of them just refuse to touch them anyway.

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MendonCycleSmith said:

Was the grease just very light viscosity, or literally runny, and came pouring out when you opened the boot? If there was oil in enough quantity to make a run down the leg with the lower boots' zip tie off, you have a leak. Typically it's the so called Quad seal at the top of the fork's rebound assembly. It seals the rebound assembly shaft as it moves through the top cap of the inner leg. Need more info?

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wadester said:

There wasn't a pool of liquid at the bottom of the boot, just a complete coat of greyish oily stuff with the black blobs. Not runny until you wiped enough together. But what you are saying is that if the rebound seal goes - you get enough 2.5wt to really float stuff. Which means that my seal is not blown, but is this normal blowby? Or CDale assembly lube?

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MendonCycleSmith said:

It is a seal in the top, that caused a bunch of leaks for many folks. It WAS a typical O ring in the past, till '005 when they went to a quad seal which looks like an O ring that went square in profile, then got all it's flats dimpled inward. It works much better, pretty simple to chagne too. As far as I know, no one has done a blow by blow on the lefty, maybe someday if I get time.........You say when replacing the rebound assembly, did you mean compression? Reason is, no oil comes out when sticking the rebound in, a bunch comes out when doing the compression. It's normal for it to come out, and you want it to, as it means the level is sufficient, and it is compensating for displacement, as you so aptly stated. If you have lots of time, you could probably get the level close enough so that only a tiny amount came out, I am happy with a little drizzle though, I typically fill to about 2" from the top, then stick it in, wrap a rag around the fork, that catches all the overflow, and make clean up easier! Remember to pop the bleed screw out to allow the presure to equalize, or you blow seals much more quickly! Rock on.

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MendonCycleSmith said:

The lube in there should be fairly tacky, if it's as you describe, you are probably getting some blow by, and ought to think about it's replacement. I had a customer that had it so bad, it would fill his boot, leak onto his brake, and effectively kill his ride. Doesn't sound like yours is there yet though.Good luck!

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damion said:

Compression is what I meant. THe next time I am in there, I will replace the o-ring with the Quad.

I am glad to hear that I am getting the oil amount OK.

I am running my rebound almost full slow. This tells me to get some heavier oil, right? (To get back to a useable adjustment range.) However, I am running the compression fully open. Any suggestions?

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wakeboardR2wheels said:

English is not your first language? Very inpressive then. I was wondering if you weren't from around these parts... I kept thinking La Cherve was goat cheese and couldn't get anything to compute! I like it! (not the cheese)

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smithersjones said:

Dear MendonCycles,
Question (it may be bad, but try to bear with me), my 2006 Lefty feels a bit to plush for my liking. I would prefer less sag and more resistance on the compression. I've filled the fork up to the max air pressure, is there anything else that I can do?

And, you mentioned that maintenance should be done periodically on 'migration' in other threads, can you explain how to do this work?

Thanks for sharing the expertise.
-CB

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