Heavy duty clutch springs.

[Liteway]

Installed this morning. Also replaced clutch friction disks with original cork type.

Tried to first order EBCs as the internet reviews said they increased effort noticeably so were surely stiffer. When I tried to order them I learned that for my particular motor they were standard, not H.D. Don't know why.
So I ordered the only other set I could find that fit my motor advertised as heavy duty, Vesrah Racing. They did not specify if they were 10 or 20 % stiffer, Only H.D.
As I have put 6200 hard miles on the clutch and I received the donor with 4000 obviously hard miles (theft recovery, totaled), I decided to order new clutch plates to install while I had it apart. Ordered EBC original type cork plates. Good idea, when taken apart original plates looked at the end of their useful life.

Result; Zilch. No difference in take up(bite) or effort.

Do you suppose shimming might help?

New springs appeared to be wound with the same gauge wire , but were a nickle thickness longer.

[jim99]

Are you using sportbike motor oil? I found from years of racing open wheel cars with sport bike motors that a quick way to "kill" the clutch dics was to run automotive oil.

My trike is 1200 lbs with me in it and has been on the road for serveal years with no clutch problems. That being said, clutch will proabaly dies this spring when I get trike out of storeage.

Jim

From Exxon/Mobile website:

"Question:
What is the difference from motorcycle oil than car oil?
-- Matt Coffman, Attica, NY

Answer:
Motorcycle oils and passenger car oils are very similar, with the exception of a couple of areas that are key to motorcycle operation. The first area concerns common sumps, or the use of motor oil, to lubricate and cool the transmission. As you know, in a passenger car the transmission is lubricated by an ATF fluid, which has frictional properties required for transmission operation. In a motorcycle, where the transmission may be lubricated by the engine oil, an engine oil that does not have the same level of friction modification (for fuel economy) of a typical passenger car engine oil will provide better transmission performance in terms of transmission lock-up and slippage. So motorcycle engine oil does not contain the friction modifiers of a passenger car engine oil. The second area of concern for motorcycle engine oils is that they tend to shear (breakdown viscosity) more quickly than a typical passenger car. Mobil 1 motorcycle oils are designed to provide exceptional protection against viscosity loss."

[DaveJ98092]

Jim, Over on the Burgman web page we have come to the conclusion that one of the best oils is Shell Rotella T6 full Synthetic 5W40. This oil is rated JASO-M for wet clutches. And a gallon costs about $20 at Wally-World. I change mine out with filter every 7,000 miles. I have 52,000 miles on my 08 Burgman 650 using this oil from the second oil change. My scooter has conventional type clutch discs that are controlled by a set of springs and rollers, kind of a variator setup.

TT, on my sons EX500 (Pre-Ninja) there was not a HD set for it. But my son is in the auto parts trade so he did some research and found a set of springs for a 1000 Ninja that were the same height as his 500's but with a much thicker wire. His bike takes 5 springs and the set came with 6. I bet the nickel added thickness will be gone in 1,000 miles or so. Bummer.

[Liteway]

Jim; Would like to know more about the trike you have featured as your avatar.
I agree that a motorcycle clutch should go far longer than 10k, but as I said, the motor was from a theft recovery found abandoned in a bar ditch and God knows what abuse was heaped upon it before it came into my custody.

Bought my first sport bike, a CB400f in Seatle in 1975 while stationed there as an Icebreaker deck hand with the Coast Guard. When reassigned, I rode it 2200 mi in 4 days to my parents house in Sherman Tx. before reporting to my next duty station on Saipan. 7000rpm (70mph)all the way. Since then I have owed a number of small/ midsize sport bikes, the latest a 2003 Suzuki 650 v twin, and my favorite was 1985 VF500 interceptor that I regret selling to this day.

Sorry, long way to make a point. I am well aware of the folly of car oil in bikes, Last change was valvoline 4T Motorcycle oil, full syn.
Anyway some of these guys building trikes have no prior experience with bike engines and its good you brought this up and posted it here.

Your racing experience might be helpful to me/others in another way. What do you think of kevlar vs cork clutch material? My best info is the kevlar is much more resilient to heat and has better bite, longer life. I didn't go with that because they are not compatible with synthetic oils, and I feared they may be tricky to slip when you need to, such as taking off on a steep slope.

Do racers use or prefer the kevlar?
Are they a good idea for street use?

[skifffz1to3]

On the motorcycle forums I frequent they would respond "Oh no, another oil thread"! I'm new here, but I have been riding motorcycles since 1973. I have amassed somewhere between 350-400k miles. I have ridden all of the "lower 48", four cross country rides, one included crossing the Mojave desert in July on a 1983 Yamaha XJ900 Seca, Inline air cooled 4 cyl.  My current bike, '02 Yamaha FZ1 has 137k plus miles on the original clutch. I have always used premium (high test, for you other old farts!) and Valvoline full synthetic 20w-50 Automotive oil in all of my vehicles. It does not have the "slick" additives that are harmful to motorcycle "wet clutches". Side note...my 1996 Chevy Astro EXT van vas 329k miles in original engine, still burns No oil. The Shell Rotella full Syn is reported to be great as well, tho I have never used it.

As to the clutch spring issue, Barnett high performance springs are awesome.

Hope this helps.

Cheers

[tinhorn]

Mar 15, 2014 20:26:00 GMT -5 Liteway said:

Anyway some of these guys building trikes have no prior experience with bike engines and its good you brought this up and posted it here.

Yup.