Jump to content


  • Content Count

  • Joined

  • Last visited

About jimjim

  • Rank
    TT Newbie

Profile Information

  • Location
  1. jimjim

    swollen clutch membrane

    Yes. If they don't charge $8 for $0.25 of rubber (I know, I'm getting hung up on principle) and please remember where this thread started.
  2. jimjim

    swollen clutch membrane

    A company named Parker Hannifin is considered a leader in the seal industry, especially o-rings. You could source o-rings from many manufacturers but my recommendation is to find a U.S. based source that won't put fillers in the material to save a buck. Many Chinese o-rings have very low quality control with respect to elastomers and it is not uncommon to find clay, recycled scrap unknown rubber and other stuff (finger nails? jk). I suggested Parker because they have distributors everywhere in North America. See the link. http://www.parker.com/portal/site/PARKER/menuitem.b7badf701c337c6315731910237ad1ca/?vgnextoid=4a51a35c7575e210VgnVCM10000048021dacRCRD&vgnextfmt=EN&divid=687519&divisionName=O-Ring+%26+Engineered+Seals+Division&catId=&catName=&partNumber=&srcTypeId=DIST_PAGE&country=United States&noun=&modifier=&divisionBrandVar=D&from=division&srctitle=O-Ring+%26+Engineered+Seals+Division I am not sure how 840 hours translates to cycles on the o-ring, but if there are 4 gear changes/clutch feathers per minute (silly wild-ass guess), that is 240 cycles per hour and about 200,000 cycles on that o-ring. I think you have done well. In an industrial application on an automated machine you would expect 2M cycles as a minimum but you could also get that in 6 months. A new o-ring is less than a buck, so there is no excuse to not change them when you have stuff apart.
  3. jimjim

    swollen clutch membrane

    Fluorinating any elastomer typically increases its minimum temperature capability. If you ride in the winter that could be a problem. There are standard o-rings available that are already fluorinated, such as Hifluor Viton and Perfluoroelastomer (Teflon). Teflon has terrible memory, so it comes off the option list. Fluorination also reduces abraision resistance which is fine for static applications and not so good for dynamic. The only other elastomer made to work with brake fluid is Styrene-Butadiene (SBR), but its limitation is a maximum temperature of 225 deg F. EPR/EPDM is the elastomer of choice and is used in virtually every alcohol based braking system on the planet. The problem is not the elastomer. I suggest finding your local Parker Store and getting an o-ring that you can be sure is made of high quality (no filler material) EPDM and trying that first.
  4. jimjim

    swollen clutch membrane

    That is a cooked (over temperature) o-ring. The range for an EPDM seal is -57 deg C to 121 deg C (-70 to 250 F) which can be achieved close to a brake caliper but very unlikely at a clutch master cylinder unless you are working the clutch a bunch and the o-ring is undersized and/or the bore is oversized causing leakage. Leaking fluid heats up. On a hot, sunny summer day the fluid can already be hot to start with and some leakage on a working clutch can start to fail the seal. I would verify you have the correct size o-ring to start with.
  5. jimjim

    swollen clutch membrane

    Rubber products swelling is text book incompatibility with the fluid. DOT4 and DOT5.1 require a material named EPDM (ethylene propylene diene terpolymer) and mineral oil requires an elastomer named Nitrile, NBR or Buna N (acrylonitrile butadiene rubber). Almost all the standard elastomers are compatible with DOT5. It is not an issue of a 'cheap' diaphragm material but of incorrect elastomer material. You have the wrong elastomer for your fluid or the wrong fluid for your elastomers. Remember that there is probably an o-ring on the clutch master cylinder piston and another on the clutch actuator. The same thing will happen to the o-rings as the diaphragm if the incorrect fluid has been used.
  6. CF will build up a fair amount of static electricity, which can piss you off every time you touch the panel if it isn't grounded. If you ever have to pull a connector from your instrument panel you could cause a problem. I would take a meter and measure the resistance between the negative battery post and the CF panel to determine how well it is grounding through the bar clamp bolts. Anything less than 10k Ohms should be adequate to prevent any significant static.
  7. Very nice job. Remember that CF is electrically conductive - make sure the panel is grounded. ­čĹŹ
  8. jimjim

    Metal in oil filter

    The stuff you can see is not what will wipe out your engine, but where there is smoke, there is fire. With that much contamination in the filter element you should be concerned that a bunch of metal made it past the filter media and into the costly parts. It doesn't matter if the particles are ferrous or not, loose metal bits are not supposed to be wandering around in your engine. Do not run the engine, dump the oil, pull a few covers and look for any signs of excessive wear, install a new filter, and get some religion. You are going to need a leap of faith when you start this thing back up again. Now that we have established that the sky is falling - Murphy's Law may not apply and you could have dodged a bullet. Either way, you need to find out where all that metal came from and fix that before running the engine. Best of luck. ­čĹŹ
  9. jimjim

    Yz125 snapped beadlock

    This is a classic fatigue failure that has occurred over a long period of time. The failure faces are polished smoothly with a very small stress failure. My guess is that the failure started with a small crack and perhaps a slightly loose nut and fatigued to failure. Is the stud aluminum or steel? It is hard to tell from the pic. The failure mode indicates it is steel.