“The first thing noticed was on warming up the Motor – we were literally shocked by the reduction in vibration. This had halved the level felt through the bars but also through the rest of the Chassis. In the past vibration has destroyed various parts including electronic Rev Counters. The Motor spun up quickly and freely. When building the Motor I was very impressed with the quality of the parts and I’m now even more impressed with the results. We’re looking forward to some good racing this year.” Steven Wall’s 920cc drainpipe Dunstall with lightweight JS pistons, longer rods, Beehive valve springs, reduced shank cylinder bolts etc. (Short vid of Steven’s 920 at speed).
Doug MacRae scores a couple wins at Mid Ohio in July 2015 on his short stroke with JSM lightweight domed pistons, Longer Carrillo short stroke rods, JS2 radius cam, beehive valve springs. Other trick componets include FA bathub combustion chamber designed by Herb Becker, 5 speed Nourish/Triumph gearbox. (View the onboard video).
John Snead roadracing in “Bears” class with JS2 cam kit
Joes’s 73 850 with JS lightweight pistons, longer rods, Beehive springs and black diamond valves, JS1 cam kit with lightweight lifters, 33mm Keihin CRS carbs, fiberglass reinforced silicone gaskets, rocker spindle covers, Turcite fork bushings and Aluminum fork sleeves
Randy Johnson does it again with another land speed record. This time at El Mirage in the 750cc M-PG class at 126.907mph. “Had some corrosion issues in the ignition connections so it didn’t run clean on the top end. Going to run new ignition wiring for the El Mirage meet in May, Hoping to run in the 130’s. The tech guys really liked it and took lots of pictures. JSM lightweight domed pistons and longer rods, Complete JS3 cam kit, ,020 copper head gasket, Beehive spring and valve kit, gapless rings.
Christian’s classic racer with JS lightweight pistons and long rods, JS2 cam, bsa lifters and one piece Beehive springs. “The power is impressive.”
“At the CRMC Croft event May 7, 2016 and the Sunday June 19, 2016 Bob Mcintyre event, Gary won all six races in his class and made fastest laps in Classic.” Dave Watson (owner). Gary Thwaites above tucked in and leading at Pembery. Gary won all seven national 1300cc classic races for the 2012 UK championship on Dave Watson’s 1007cc Seeley with JSM Motorsport lightweight pistons, longer rods and stage 3 cam kit with lightweight radiused lifters. The longer rods and lighter pistons gave more power and appox 1000 RPM. “The engine is much smoother and power up…we are well happy with the bike and all your gear that is inside the engine…Gary rode the big Norton in two CRMC meetings in 2013 at Cadwell Park and Donington and won all his five races.” Gordon Humphreys (tuner).
David Blanken
Maria Costello winning races in Bears class at Daytona and Barber 2011 on the Dan Rose 750 Seeley with JSM lightweight pistons, longer rods, stage 2 radius cam with lightweight lifters and beehive valve springs. This is one of the fastest long stroke 750s on the tracks. Photo courtesy of Lisa Theobald.
Michaels prefect 850 with Lightweight pistons and longer rods, JS0 cam kit, Beehive valve spring kit and Keihin CR33mm carbs. “bike runs fantastic”.
Shane’s 70 Combat with 33mm Keihin CRS carbs
Proud owner Giacomo Cavecchi, from Italy, with his beautiful 850 Commando running JS Motorsport lightweight pistons & rods.
Stan Keys winning the AHRMA Bears Championship in 2017 with complete JS2 smooth ramp cam kit.
The first bike to win a race with our lightweight pistons & longer rods. Owner Herbert Toscany
Nigel Waring
Herberts Seeley
Constanine’s 750 racer with JS lightweight pistons, gapless rings, longer rods, JS 1 cam kit with lightweight lifters, Beehive spring and valve kit, reed valve breather, 33mm Keihin CRS smoothbore carbs, silicone gaskets. “It is so friendly and rideable with a nice torque curve.”
“Jim, just a quick note of thanks. Took the Seeley Norton racing this weekend (April 2010). The balance was absolutely spot on just fitting your pistons and rods. The motor starts well and pulls like a train all the way up the revs with no perceptible vibes. It was a real boneshaker before! I’ve had folks wanting to know what has been done to the motor to make it so smooth and tractable. Thanks again Jim.” Norman (Scotland UK).
“After a shake down at Pacific Raceway in Seattle I got the bike down to Willow Springs for the AHRMA Nationals (May 2010). Took 2nd in the Bears class. Vibration was not a factor (JSM pistons & rods), and the bike pulled strong, with a noticeable increase in power (stage 2 cam kit & lightweight lifters). I’m pleased thus far.” Jesse Seary (British Columbia Canada)
Here’s where the lightweight pistons started – Jim Schmidt at Willow Springs raceway in the mid 1980s. Pushing his Norton monoshock 850 to the max.
Jim Schmidts monoshock space frame as in the action photo above but naked without fairing
The Dan Rose 750 Seeley racer full of JSM components – lightweight pistons, longer rods, .003 head gasket ring, stage 2 radius cam with lightweight lifters and beehive valve springs. Won its class at Daytona in 2011.
Jordan Baber riding Kelly George’s successful 750 flattracker with lightweight JSM pistons/conrods and JS stage 2 cam.
“On the track with my Seeley Norton with JSM pistons and conrods inside. Very good engine, very powerful on the mid range. I left a lot of other Nortons behind on the straights and out of turns.” Lucas
Enjoying his first ride down the Australian coastline after installing the smooth running lightweight pistons & longer rods – Ian Palmer.
920cc Seeley with JSM lightweight pistons, longer bushless rods, stage 2 cam, lightweight lifters. In 2010 it tied exactly with the 1000cc pushrod fuel, unstreamlined, Bonneville land speed record at 150 mph. In 2011 it achieved 155+ HP at the crankshaft on Nitrous. “Jim, I’m really impressed with your products, it runs SO MUCH SMOOTHER with the lightweight pistons.” Fred Eiker
“Hi Jim, I’ve finished my bike and it runs and sounds great. Your camshaft and lightweight lifters seem to make the bike feel different in a very good way. It has less vibrations and is quieter somehow. It feels like it has more accurate combustion too, I suppose this is due to the curved lifters. Thank you for selling me the kit. I am so pleased with it I put your stickers on the sidepanels.” Petter Olden
Jim Schmidts wideline Atlas test bike with lightweight pistons, JS 0 cam kit, JSM carbs, Beehive springs, Hunt magneto and all the rest of our trick components. Good for roll on wheelies and 80mph cruize (4:1 gearing). Less than 1% leakdown with 40,000 miles on the rings and pistons.
“The slower piston speed (at TDC) combined with the light weight certainly makes for a lot less stress and vibration”, Jim Cossin’s (AKA Commando Garden) is enjoying his 750 with JS lightweight pistons, longer rods and gapless rings. Crank rebalanced to 58%.
Paul Coughlan’s race 850 Commando in Australia with lightweight pistons/longer rods, JS stage 2 lightweight lifter cam kit, beehive valve springs.
Stunning featherbed 850 owned by celebrity song writer Billy Joel. Sporting JSM carbs.
Canadian Michael Mackin’s ’69 Commando, restored to perfection by Garrie Cook, complete with JS Motorsport pistons/rods. “Runs very smooth and quiet”.
Bruno Waltersbacher’s 850 Seeley racer with JS lightweight HI comp pistons, longer rods, JS1 cam kit. Dynoed at 78 HP. See a dyno run of early version of the motor HERE.
Lars Poulsen’s race ready Commando with JSM lightweight pistons and longer rods
“Jim, here’s the pic of the long awaited finished bike. Steve [big D cycle] said it’s the smoothest 850 he’s ridden. It surprised Keith [big D cycle] when it did 60HP between five and six and a half grand at the rear wheel on the dyno and at 5K sounded like it shifted into a higher gear or someone turned on the nitrous! Thank’s for all the good products.” [JS lightweight pistons, longer rods, JSM carbs, stage one cam & lightweight lifters, beehive valve springs] Brad Baird
Ralph Coldwells 850 with lightweight JSM pistons/conrods and JSM carbs.
Mike Hamilton’s 850 with lightweight JS pistons/conrods, JS Stage 2 radius cam kit, beehive spring & valve kit, turkite bushings, 63% crank balance. Showns 74 HP on the dyno.
Stuart Metge’s 500 dominator with ultralight JSM domed pistons/conrods, Stage 1 radius cam kit, beehive spring & valve kit. SS 650 head. Revvs freely to 8000RPM
Victor Vassella’s 920 featherbed with lightweight JS pistons/longer conrods, 130+ on the straights
Yves Van Heer’s perfect 850 Seely with JS lightweight pistons/longer rods, gapless rings, JS2 cam with lightweight lifters and custom billet 23 lb crank balanced at 65%. “The engine is working great, without vibes and when you reach 5.000 rpm you go amazingly fast to 6.500 rpm (62 BHP/5900 RPM at rear wheel). When I am on roads and I stay between 5.000 and 6.500 and go down or up in the gears at every turn it is a song of joy… The lightweight lifters and valves springs are also top of the game. I don’t touch the engine since 10,000 kms and this never happened before. And believe me, I ride hard” Great work Jim
One of the fastest period roadracers in Australia with JS long rods and special lightweight 850cc 14:1 C.R. domed pistons for Methanol. JS big valves and Beehive springs. JS3 cam with lightweight lifters. 80+ HP, 140+ MPH, Does 11+ sec in the 1/4 mile. Classic unlimited champion in 2017. Proud owner/rider – Garth Francis.
Side car belonging to Australian Garth Francis using JSM long rods and 850cc lightweight domed pistons on methanol.
Swedish racer Per Holmstrom on his 750 with bathtub combustion chambers, JSM high C.R. pistons/longer rods, beehive spring & valve kit, JS stage 3 cam.
German racer Bern Schaefer on his 850 with JSM high C.R. pistons/longer rods, beehive spring & valve kit, JS stage 2 cam. Motor revvs to an amazing 8400 RPM producing 75 HP using 33mm keihin CRS carbs.
French racer Bruno Perlinski on his 750 short stroke with lightweight JSM domed pistons/longer rods, stage 3 cam, Beehive valve springs, rocker spindle covers
Perlinski’s row of Seeleys. The bike in the foreground uses a 270 deg short stroke crank with JSM internals is winning races in France with Steve and Bruno Perlinsky riding.
I placed 2nd in 1984 at the Laguna Seca 750 BOTT AMA National with this 750 slimline featherbed. Long homemade 35mm Guilotine slide carbs, Very fast. Fred Eiker and I traded 1st place every lap at this race. These were the days when we first started dragging our knees.
Mark Gunning’s better than new 850 with CRS 33mm carburators.
Dennis Donahoe, winner of the 2015 pacific coast championship. This extraordinary Norton was built in 2010 and has 40 race events on the lightweight pistons/longer rods & JS2 cam. “The motor has had no issues and is still running strong”.
Custom Commando racer I built for Rod Hurick in the 1980s. Box swingarm with eccentrics, Alloy oil tank, alloy engine cradle, Motor built to Axtell specs.
Ken Canaga’s mono shock 920 (JS space frame). With Rob Tuluie riding it was the last Norton to get on the AMA podium. 3rd place in Pro Twins GP2 at Willow Springs against a field of monoshock aircooled Ducatis in 1990.
John Puhakka in Finland on his 750 Featherbed with JS lightweight domed pistons/longer rods, JS stage 2 cam, Beehive valve springs and big valves, Turcite fork bushings
Brian Coopers 8500RPM short stroke 500 domni with JS2 cam kit and beehive springs. “with your parts fitted for this years classic TT the bike flew with no problems”.
Michael Panayi’s featherbed from down under. “I currently have 2 race engines (750 & 920) that have your pistons and rods which have been winning plenty of races.”
Andy’s 750 shortstroke land speed racer with JS domed pistons and longer rods. JS2 cam, A solid 75 HP on the dyno. Herb Becker (tuner) on left.
Andy’s land speed racer with fully developed 95 HP 920cc motor. It achieved an amazing 154mph on the Bonneville salt flats in 2018 with JS light weight pistons and longer rods. The fastest unstreamlined, naturally aspirated gas powered Norton on the planet. Tuned by Herb Becker
Robert Hood and passenger Mark Thompson won the New Zealand Classic Motorcycle Racing Register (NZMCRR) Post Classic Sidecar Championship in 2013, 2014 and 2015 and still at it in 2022. Lightweight 920cc JSM pistons and longer rods. Maney cases and Barrels. One piece crank by Graham Martin in NZ. 36 mm Dellorto’s. 15:1 compression on methanol. 75 ft lbs torque and 86 BHP at the back wheel. 97 races and counting on the same lightweight pistons and rings.
Les Clark’s Seeley with JSM 33mm CRS Smoothbore carbs. “Pulls like a train.”
“Hi Jim, I’m finally sending you those promised pics of my ’64 Atlas. She’s done 7,000 Km now. The engine has your lightweight pistons, Carrillo rods and complete Stage 1 cam kit. What can I say, the engine is unbelievable, makes the bike a joy to ride, and gives the later model Trumpy twins a serious run for the money.”
“I’ve got a 750 Atlas with your long rods and lightweight pistons installed and your recommended balance factor. Having undertaken a complete restoration on the bike…and am very happy with the vibration levels.” Tom
Redento’s perfectly restored 750 with JSM lightweight pistons/rods and Beehive valve spring kit. “The bike is working very well, very little vibration. Compliments, I am very satisfied.”
“Hi Jim , I have just finished rebuilding my 71 Commando. We used your lightweight pistons, rods, lifters, street cam, beehive spring/valve kit and a set of your Keihin carbs. It starts first kick and idles well, those carbs are great.” Gareth
Jan’s 850cc powered N15 with JSM lightweight pistons and longer rods running “very smooth”.
Hot Combat with JSM performance parts and Gorgeous adornments.
Redento’s Bonnie with JSM Lightweight bushless Carrillo rods, DLC pins and stock pistons. Rod weight is the same so rebalancing is unnecessary
John Pitchers 650 SS Domni racer with JSM Hi. CR. lightweight domed pistons, longer ultralight rods, JS2 cam kit and CRS Keihin carb kit.
Roger’s 57hp 500cc in Canada with JS2 smoothramp cam kit. “Ran great all season and won every race in the 500 period 1 class… It seems happy to rev to 9000 rpm.”
Steve Adlem on his shortstroke with JSM bushless rods, high C.R. pistons, Beehive springs and black diamond valves.
920cc Featherbed with JS2 270 deg cam.
Ian Salters sidecar racers with JSM lightweight pistons, total seal rings, longer rods, JS3 smooth ramp cam, big valves, beehive springs, .003″ thick ring head gasket, etc.
Mats Hall’s shortstroke taking 1st place in the Swedish cup formula 750 in 2017 with graphite coated JSM lightweight pistons and longer rods, custom cam with JS2 exhaust and JS3 intake lobes. Dynoed with 80 HP at the rear wheel.
Pierre’s immaculate Seeley with JSM lightweight pistons and longer rods, JS2 cam kit with light weight lifters, Beehive springs & valves, fiberglass reinforced silicone gaskets.
Lyndsay’s 500 Dominator with JS2 cam kit and Beehive valve springs. Click HERE to view the onboard video.
Mike Hardings immaculate 85HP 920cc Peter Williams replica with lightweight pistons, longer rods and JS2 smoothramp cam. Twice over revved to 10,000 RPM due to clutch problem with no ill effects. Photos by Tony Else. See a him wheelie off the starting lineHERE.
Ralph Coldwell’s polished 75 HP 920cc Seeley with lightweight pistons, longer rods and JS2 cam.
Rainier’s 750 Bonneville LSR with lightweight pistons, longer rods, JS3 cam, big valves with Beehive springs and forced air induction putting out an amazing 85 HP on the dyno
Steve’s 920 with JS lightweight High Compression pistons, longer rods, JS1 cam kit with lightweight lifters, JS Beehive springs.
Wade’s 920cc featherbed in Finland with JS lightweight High Compression graphite coated pistons and longer rods.
Jeff’s Cruiser punched out to 920cc with JS lightweight pistons, longer rods, JS0 cam kit and beehive spring & valve kit.
Randy Johnsons 3rd 750 speed record. Raising the bar to 130mph at Lake Mirage in 2022 with JSM lightweight domed pistons and longer rods, Complete JS3 cam kit, .020 copper head gasket, Beehive spring and valve kit, gapless rings.
Brian Riley’s 500 Domni racer with lightweight domed pistons, ultralight rods, JS2 cam and beehive valve/spring kits. “I got out yesterday on the bike and got 80 miles on the engine since the build. I couldn’t help but open the throttle and took it to 6K Revs and I got to say it was like having 2 after burners on the back of the bike it just pulled like a train!!! very impressed so far and the vibration has been reduced massively I can actually keep my hands on the bars!!”
“Jim, I’m using your beehive springs, JS2 complete cam kit, long rods and high CR pistons in a +.040 750 with a mildly ported head. It has very usable torque for the street and really wakes up at higher RPM. Overall, a big improvement for me over the Norton 2S cam I was using. Great job with the smooth ramp design.” Steven Schwander
Bruno Perlinski’s 750 short stroke with JS long rods, lightweight pistons and JS3 cam on the track in 2022.
Left on the podium in Belgium at Chimay. “I finish 2nd with 750 short stroke, my 270 degree crank, your long rods with lightweight pistons and your JS3 cam. The engine easily makes 8000rpm!”
Tim Horton’s 1007cc with lightweight pistons, longer rods, JS3 cam etc. “Bike is running well, 5 wins out of six last time out. Still out drags a weslake 900 side by side.”
John Curry’s 850cc 61 manxman with lightweight JSM pistons and rods to smooth out the vibes. JS0 cam kit.
Bernie’s 750 fastback with JSM long rods, lightweight pistons, JS1 cam, Keihin CRS carbs, reed valve breather, beehive springs and black diamond valves. “wholly heck does the girl go!” (Short vid of Bernie’s idling fastback).
Haru’s 750 racer with JSM long rods, High comp lightweight pistons, JS2 cam, beehive springs and black diamond valves. (Short vid of Haru’s racer).
“Just rebuilt my MK3, got the engine installed and fired it. I am completely shocked how much smoother this bike is… this motorcycle is much faster than it was… Looking forward to getting some more miles on it.” Eric’s 850 with JS lightweight pistons, longer rods, total seal rings, JS2 camkit with lightweight lifters, black diamond valves and beehive springs, sump reed valve breather, Keihin CRS carbs, fiberglass reinforced silicone gaskets, RH4 to RH10 intake port tube conversion.
