Hi everyone,

I got the BB kit, 631 cams,, manual cam chain adjuster (thanks KLX678) and carb jetting (thanks Klxster) installed and boy, what a difference! I have about 100 miles on so far and it rocks. So much low and mid range torque it just feels like a tractor.
I built a set of wheels with road tires so I could swap out quickly from off road to road duty and with the 130/70/17 tire on the back, I noticed that the clutch slips when I put a load on the engine in 3rd, 4th, 5th, and 6th. I have already put the stiffer Barnett springs in and the clutch pack measured within specs so I left it as is when I re-assembled the engine with the new cam chain.
People on this forum seem to recommend the EBC DRC212 clutch pack for the BB 351 kit. I'm just reaching out to 351 kit owners for their advice...let me know your thoughts-thanks, Mike

 

I did with Barrett springs and it works pretty good for Road riding.

 

As I'm sure everyone knows, only "wet clutch compatible" engine oil can be used.
Running the wrong synthetic oil guarantees clutch slippage..

 

Truth.
Dino Squeezings for me.

 

I've got about 2500km on my 351 and haven't had issues with clutch slipping (yet). I use dino oil if that makes a difference.

 

I run into this when I use full syn Rotella.
If I use conventional Rotella, it's fine.

 

I ran into the same when running syn oil few years ago. New clutch and semi syn kawi oil and haven't had an issue since. I am running the heavier springs as well

 

Thanks all, I am running straight Dino 10W40 since I am still breaking the engine in. I didn't notice the clutch slipping with the lighter 110/18 Kenda Trackmaster but with the 130/17 Kenda K681 I definetely noticed it slipping in the upper gears under load. I found a solution on Mr. DUH Factor's site where he contacted Barnett and they advised him to use 3 (every other spring) of their part number 501-40-06017 (38 lb. springs) in his highly modified BB351 KLX. It worked well so I think that is the path I will take.

The title of his video on You Tube is

"KLX 351 Slipping Clutch Solution"

 

"Dino Squeezins" , LOL

Cracks me up every time !

 

That should fix your clutch problem. The OEM setup is not that stout. Used in some decently hard off road stuff even without a BB kit, the OEM clutch usually gives up fairly quickly. Mine is decently modded with a bigger bore and used fairly aggressively off road. Having done a mix of upgraded parts in my clutch, I've never had any issue even using Mobil 1 synthetic. I think the biggest factor is the wimpy factory clutch. My clutch was slipping in the first year still in basically stock power setup.

Modern wet clutches should stand up to synthetic oil. In numerous bikes over years, I've never had an issue with M1 and my clutch unless I heavily modded the engine and rarely even then. Even then after beefing up the clutch pack...different ways depending on the bike...synthetic oil never seemed to present an issue. Many, maybe most, Japanese bikes tend to have soft clutches for rider ease and less shock to the more expensive tranny components, but they still appear to do just fine. The KLX in 300 and 250 form has always had an overly soft OEM clutch.

I'm not stating this to put people off of straight dino oil or the blended versions. Most of us don't run our oil until it turns to sludge anyway...LOL! I just like the slightly better durability of a good synthetic and the way the transmission performs in synthetic...yes...I can feel the difference, and I hate missed, sketchy shifts on a steep side hill...LOL!