This happened twice now today during a ride in the city. I will be going down the street at a decent speed then when coming up to a red light i will shift down from 2nd to 1st using the engine + brakes to slow me down and there is the worst noise, a clanking/clunking or metal skipping/stuttering noise comming from the front of the bike which stops when i pull in the clutch. At first I thought it was my brakes, but I tested that out with some quick stops only braking.

It only seems to happen during hard enging braking in 1st gear. This is frist time this has ever happened. Off the top of my head the only thing that has changed from today to the past is last/last sunday I changed over to 15w 50 Syntheic Mobile One oil. Im assuming that the previous owner used 10w 40 Regular oil . Could that be my problem? I know that some oils can cause clutch slippage. Or could it be something unrelated to the clutch?

bike had 15000 miles on it. at time of change from regular to synthetic.

 

Tried to do a search for the oil, Mobil have two synthetics for bikes in 10w-40 & 20w -50 listed. If you have used oil meant for a car, it has detergent in it, which causes the wet clutch in your bike to slip, change it immediately!!!!!!!. If its bike oil, could be your CCT making the noise.

 

The oil is in fact automobile oil, but it is not energy concerving. I used it after a friend who ownes a ducati suggested it, and after i did some reading on cbrworld on this specific oil.
http://cbrworld.net/forums/thread/18427.aspx

My cct does make the ball bearing noise/feel, so im sure its in need of repalcing, but for the time being I guess Ill drain it this weekend and put regular 10w 40 in it unless someone has any other ideas. It sucks to have to drop another $20 on oil.

this person might have a similar issue:
https://cbrforum.com/m_88720/tm.htm

 

Unless someone comes in and tells me I'm wrong, I checked out the link you posted & it seems a lot of guys are using this oil, so maybe I am. Wot usually happens with car oil, as I said before, they put detergents in, (usually under the heading of "Additives" but they don't call it detergent) makes the oil slipperier, but on wet clutch bikes, car oil additives coates the plates & stops them from being able to grip, so under load they slip
I think that Dukes (or at least most of them) have dry clutches & some use hydraulic clutches (have a resevoir on left side of the bars) to overcome the amount of pressure you need to pull the clutch in, so they can run car oil without probs. My Honda handbook specifically says not to use it.

 

dont go from syn to reg. you can never go back, you can switch from semi. syn. to full syn. and vise versa but not to regular again

 

Drive down the road in probably 3rd at higher rpms, then pin the throttle. If the engine races and gets louder, but you dont gain much speed, your slipping.

 

I read on an oil analysis page awhile ago that as long as the oil isnt 'Energy Conserving' then it is good for a motorcycle. I use Rotella T 5w-40 syn oil and have never had a clutch problem.

As far as Ducs goes, some use a dry and a lot of the newer ones use a wet clutch. A lot of those guys use Rotella like I do, and no problems, wet or dry.

 

+3 on the Rotella T 5w-40