Judder engaging clutch from takeoff - sources? Lifan X-Pect
 

Hi All,
I caught the bug 6 months ago and first picked up a Hawk DLX for myself. I was so impressed, I also picked up a Lifan X-Pect for my GF (the Hawk was perfect for me, but too tall/heavy for her, and the Xpect is just right for her).

The Xpect has about 70 miles on it, and when I engage the clutch from a stop, I get a lot of clutch Judder. Happens no matter if its hot or cold. There is no judder when clutch is fully disengaged or fully engaged - only when slipping it primarily from a stand-still. In my mind that rules out things like dragging brakes, chain with tight-spots, etc (I also checked these separately). Its probably been doing this since I uncrated it, but I don't recall. I tried a few clutch adjustments and interestingly when I adjusted the clutch to be too tight (drags just barely when disengaged), the judder goes away. This lead me to believe the cause was warped frictions/springs. FWIW I am running Rotella T4 15W-40, and we primarily ride on acres of our property which is mostly dirt and some paved roads.

I suspected it was just bad clutch frictions/steels, and got a full replacement clutch (steels, frictions, springs, basket, etc) from the place I bought the bike from. Figured I would just do a quick swap and not waste a lot of time Sherlock'ing it. I swapped the clutch out, readjusted, and it did not improve the judder at all. So I'm a little befuddled. Did I get another set of bad parts, or is something else causing the judder?

Looking at the Lifan diagram, the only clutch parts that were not replaced are #1 clutch lifter, #2 clutch pusher, #3 bearing, and #11 thrust washer. I'm somewhat suspicious of the bearing, pushrods, and pushrod bore. I bought a new brand-name 16003 bearing to try, and will measure and inspect the rest of the parts.

I plan to dig into it again soon, and this time will be taking a lot of runout measurements on all the components, put the frictions/steels on a granite plate and check with feeler gauge, etc. But before I get that far I wanted to get some input on what else could cause this, in case I'm completely overlooking something else that could be contributing?

Loose engine mount bolts will do that.

For what it's worth, this is my 2nd summer with a new X-pect and while it does not have a judder at takeoff, it often has a kind of rusty sounding squeak if I take off a bit aggressively, especially in the morning when I'm first getting going. Doesn't seem serious enough to bother with but I'm keeping an eye on it. I also run Rotella T4.

Good suggestion - I checked those also, and they were tight

Hi Fellas,
Well its been a year since I posted, but I did fix the clutch judder issue on my Lifan Xpect. So I wanted to follow up to my post in case anyone winds up with a similar issue. To recap: I had pretty severe clutch judder when engaging the clutch from a stop. I had previously gotten a full replacement Lifan clutch assembly (steels, frictions, springs, basket, etc) which I installed but made zero improvement.

I recently took everything back apart again, and inspected thoroughly. I checked thickness variation (micrometer) and flatness (granite inspection slab and feeler gauges) of the frictions, steels, checked runout of the clutch pushrod on v-blocks, and a few other critical interfaces. There was no “smoking gun” that I could find.

So I bought some new parts and changed a few things up, hoping something would make a difference. And long story short I have succeeded in fixing the issue 100%, although I can’t pinpoint exactly which part or parts solved the problem, so here is a rundown of everything I did:

• I swapped the Lifan frictions for EBC frictions from whygostock (these: https://www.whygostock.com/clutch-fo...c-250cc-lifan/). I suspect they are #CK1119, but can’t confirm. The inside diameter of the EBC’s is larger (91mm versus Lifan which is 83.2mm), but they work just fine. See photo for side-by-side comparison. It is apparent to me that the construction might be a tad different based on comparing the friction material between the two (the EBC’s appear to have more cork).
  
  
• I re-used the Lifan steels (they measured in spec).
  
  
• I replaced the Lifan springs with EBC #CSK41.
  
  
• Although the bearing felt fine, I went ahead and replaced it with a new old stock Koyo 16003. (Beware of counterfeit bearings!)
  
  
• I lubricated the clutch cable with PJ1, and adjusted per the manual.
  
  
• I normally run Rotella T4 15W-40, but opted to change it up this time and used Valvoline full synthetic motorcycle 10W-40 (it’s what my local auto parts store had on the shelf).
  
  
• I also soaked the frictions for a full 24+ hours in the Valvoline.

After all this, the clutch is silky smooth and we are very happy with this little machine!

:clap:

just for laughs,, did you at anytime before checking the clutch plates out change oil?? you got new stuff from lifan but was that using same oil.. do you remember what you were using before the change to the valvoline you show in post?? :)

maybe you used these frictions..

https://www.whygostock.com/ebc-upgra...t4-7-clutches/

Yes, oil was changed multiple times with the original 'as-delivered' clutch (clutch #1) as well as Lifan replacement clutch (clutch #2). Oil changes made no improvement to the judder with either clutch. Old oil was not re-used, however the same type of oil was used for all oil changes (Rotella T4 15W-40). I use the Rotella in all my other bikes, including a Hawk DLX but opted to swap over to the Valvoline on the EBC clutch (clutch #3) just to further change up the contributory variables.

These are the frictions I used: https://www.whygostock.com/clutch-fo...c-250cc-lifan/