Occa's Li'l Thumper

Hello Rick,

I have compiled a not so short biography of L'il Thumper. Feel free to edit it as you deem necessary. Thanks for the invitation & opportunity to participate in your worthy site. Do you have an insatiable fetish too?

G'day. My name is Occa and I live in Brisbane Australia. For over 25 years I've had this insatiable fetish for old XL's. This one was originally modified in 1980 with a 250 motor bored to 305cc. In 1988 we rebuilt it including boring it to 312cc and stroking it to 364cc and it has evolved over the past two decades to what it is in the photo.

With the 364 motor, my wife, as pillion. and I attended many bike rallies all over the state of New South Wales clocking up more than 30000Km in a couple of years. It happily cruised on 140Km/h and had a top speed of 160Km/h......just. Not bad for two-up though!

In 1992 we moved overseas to Papua New Guinea. This saw our now tired steed, with damaged cam journals due to an ill-fitting aftermarket clutch cover gasket, (Watch out for these!) stored in a shipping container for the next six years. During this time it received its current paint work....two-pack for the tank, guards & headlight shell and hand brushed hammertone paint for the frame & fork legs. Don't laugh....it is proving to be quite durable and really inexpensive!

We took one of our XL350s back to PNG with us in 1996 with the intention of racing at the Goroka Speedway Club which we did for the last part of the '96 season. As fate would have it, the third corner of the first race during the last '96 meeting saw the two inlet valve heads snap off and embed into the piston but not before they severely altered the profile of the combustion chamber. Time for a rebuild me thinks!

After a small amount of deliberation, the head, barrel & crank were sent off to the good folks at Powroll Inc in Oregon USA for some restoration and, more importantly, lots of modifications. After a year or so (PNG Post took 10mths to USA via sea mail) all the goodies came back ready for assembly. The rebuild did not occur for another six months as we moved back to Australia and when it did occur, the XL350 "Motocross" rolling chassis was not completed so we dropped the newly bombed '350' motor into L'il Thumper as you see it in the photo.

The bike runs a 15T front sprocket with a 37T at the rear. The motor pulls like no other thumper I have ridden and although the front end could be a little less harsh, it handles sweetly with brilliant ground clearance. XLent!!!!


ENGINE, 1973 Honda XL350 Bore x Stroke 86 x 77.3mm Compression Ratio 10.0 : 1 or close to Capacity 449cc Head Ported & Flowed by Powroll Inc Valves & Springs Stainless Steel 1mm oversize & heavy duty with titanium retainers Camshaft Roller-bearing journals with a 'Radically' profiled lobes Mikuni 36mm with K&N air filter Exhaust Power tuned header by Powroll with SuperTrapp silencer Other Mods Heavy duty clutch springs Later model XL350 counter shaft with wider kickstart idler gear

FRAME, 1972 Honda XL250 with braced swingarm and Yamaha SRX250 foot pegs & linkages FRONT SUSPENSION 1974 Yamaha XS650 REAR SUSPENSION Koni 7610-1277 shock absorbers FRONT WHEEL 1974 Yam XS650 hub & single disc with 18" Akront rim Michelin A48 90/90H18 tyre REAR WHEEL 1972 XL250 hub inc. std drum brake with 18" Akront rim Michelin M48E 110/80H18 tyre OTHER STUFF Petrol Tank - Modified CB450 with 20 litre capacity Seat - Modified XL250 shortened, stepped & recovered Instruments - 1974 Yamaha XS650 Headlight - 1974 Yamaha XS650 Rear guard/Tail light - Modified CB125T

Other Steeds In The Stable

1972 Honda XL250 in original & good condition with the exception of paint work
1975 Honda TL250 Trials in original & good condition
1976 Suzuki RL250 Trials in original & fair condition (Horrible two-stroke)
1973 Honda XL350 Motocross "showbike" (as mentioned above) The frame is finished with two-pack epoxy, stainless cap head bolts everywhere, HPC coated forks & hubs, polished rims with stainless steel spokes and eventually the above 449cc motor. (Due for completion soon)
1973 Honda XL350 Cafe Racer. This has a Yamaha FZR250R front end with alloy 17" rim & twin discs, FZR250R 17" alloy rear wheel with single disc, CB72 combo headlight & intruments, Suzuki Katana 650 petrol tank & seat, etc and will be powered by an XL350 motor bombed to 480cc. Yum. (Due for completion when spare money comes along)


Paul O'Carrigan

L'il Thumper LeanSide