ny shop serious about building high-performance late-model Twin Cam engines will want this latest tool-set from JIMS. So, for that matter, will engine builders interested in making any Twin Cam engine the best and the strongest it can possibly be. In both cases–no pun intended–the work starts right at the bottom. The weak link in those late-model 88- and 96-inch Harleys (and it’s a notorious one when the horsepower begins building) is the left-side crankcase bearing. OE, it’s a straight-style roller bearing. Switching that bearing for the much more robust Timken bearing–a bearing style used in earlier Harleys, by the way–substantially toughens up the entire bottom end. It’s almost become a “must do” conversion, something especially true when those 88- and 96-inch Twin Cams become really big-inch motors, 117s, 124s or larger.
     This isn’t a simple job. Converting to a Timken case bearing is hardly a do-it-yourself proposition so, as they say, don’t try this at home, kids. But for a pro-shop it’s a procedure that must become familiar, and now it’s something that can be comfortably performed in-house. With the new JIMS tool-set no special machine-work is required. The key to it all is the JIMS No. 956 Timken Bearing Conversion Sleeve and the No. 959 Twin-Cam Timken Case Conversion Tool Set. The JIMS sleeve, and the tool set to install it, eliminates all the specialized machine work previously required for this job. All that’s needed now–along with that sleeve and the JIMS tool-set to install it–are ordinary hand tools and a 2-ton shop press.
     The specialized tools, fixtures and equipment JIMS supplies allow this all-important bottom-end upgrade to be completed in any well-equipped shop by a savvy technician. JIMS designed this tool-set to eliminate the need to send those cases out for Timken bearing machining. A precision tool-set easily and accurately converts that left-side crankshaft roller bearing (H-D No.24604-00D) to the more durable Timken bearing (H-D No.9028). JIMS Conversion Sleeve Insert makes all this possible, and it’s manufactured from aerospace-quality steel that’s several times stronger than the aluminum case material the standard bearing rides in. That new sleeve installs directly into the stock Harley case and then the Timken bearing installs into it. The conversion works on all Twin Cam engines from 2003 to present.
     The JIMS tool-set includes a new steel bearing insert held to under .0002-inch total indicator reading (more are available separately) along with everything needed to install it. All the special locator plates, pressing plates, drilling guide fixtures and the required drill bits themselves in the proper sizes and with locking collars to assure correct depths are included. Nothing’s been left to chance and everything needed is in the tool-set. A special JIMS press plate (No.959-2) will hold the bearing insert in-line with the case bearing bore as it’s being pressed into the case, all the necessary drill bits to drill the required oil feed and return holes are included, all necessary hardware comes in the tool-set and there are detailed instructions to guide you through every step of the way. All the tools and the insert sleeves are manufactured in-house at JIMS USA in Camarillo, California. There’s even a full listing of all the sprocket-shaft spacers that’ll be needed after the Timken conversion to maintain proper primary-chain alignment between the clutch basket sprocket and motor sprocket. It all comes packed in a handy, protective case and treated correctly, as any precision tool-set should be, it’ll provide a lifetime of use.
     Plenty of riders are opting to keep their Harleys a little longer these days. Lots of those Twin-Cam engines are being made a little bigger, too. A Timken bearing conversion is a required part of that deal. With the JIMS Bearing Conversion Tool Kit all that can happen in-house now, with no special machining required. JIMS has long been the go-to supplier for all sorts of handy and specialized tools to help out in the shop. This newest one, the Timken Bearing Conversion Tool Set and those Bearing Conversion Sleeves, is a dandy. It’s available now.


All necessary hardware comes in the tool-set, too, and there are full instructions to guide you through the conversion every step of the way. JIMS has even included a full listing of all the sprocket-shaft spacers that’ll be needed after the Timken conversion to maintain primary-chain alignment.


A 2-top shop press is the only extra piece of equipment needed. Everything else required comes in the JIMS tool-set, all the special locator plates, pressing plates, drilling guide fixtures and even the drill bits themselves.