- Oct 13, 1999
- 2,807
- 0
Seven years ago I “won” this pile on e-bay.
It’s actually a 1973 Bultaco M-98 (175) Alpina. While it was fairly complete, the cosmetics left something to be desired. Upon picking the bike up I found a lot of issues. The tank and seat were not correct. The exhaust pipe, coming fron the cylinder had rotted away. The front brake lever and cable were missing and the clutch and throttle cable were stretched. The tires were dry-rotted and RTV silicone oozed out from the cylinder to case joint. I had bought the bike in hopes of getting I ready to ride the 2003 ISDT Reunion Ride (Vintage Enduro).
I began stripping the bike down, but most important I wanted to make sure the engine was sound. It wasn’t!
Upon disassembling the top end I discovered the connecting rod piston pin journal was badly galled. This meant I needed to split the cases. Unfortunately, due to baby # 2 in the oven, funds for this project dried up quickly and most of the pieces ended in one corner or another of my garage and basement. The Reunion Ride came and went, but in the summer of ‘04 I started piecing it back together. Along the way I discovered many things. While the bike was originally built as a 175, somewhere along the way a 250 jug and piston was installed (the 175 and 250 share the same stroke). Being as thrifty (i.e. cheap) as possible I hunted down parts from every Bultaco supplier out there.
Finally, in October of ‘04, I got it running. My maiden ride was the 2004 SMOG (Spanish Motrocycle Owners Group) East Trail Ride.
First Ride Video
All I can say is riding a vintage bike, especially one with right-side shift/left-side brake, really makes you appreciate a modern bike!
After getting all the bugs worked out I rode the Alpina in two more SMOG rides and a couple vintage trail rides. Unfortunately having the shifter and rear brake on the “wrong” sides always through me for a loop. Most of the time it sat in my garage collecting dust. Then in 2007 I was convinced to participate in a vintage trial. Since the Alpina shares the same frame as the Bultaco Sherpa-T (trials model) it lends itself very well to a stand-up riding position. However it takes more than just mounting a set of trials tires to set-up an Alpina as a trials bike. So after my first miserable experience I went about making the Alpina into a Sherpina.
First I located the slimline tank/seat from a Sherpa-T. The tank required some fiberglass work, sealing so it would hold fuel and a rattle-can Earl Schieb. Meanwhile a friend made a new seat pan out of fiberglass, cut some foam and recovered it. The tank holds over a gallon less fuel and the smaller seat makes it easier to maneuver around to maintain your balance at low-speed. Next I installed a set of low-front fender mounts which aids in aiming the front tire while plonking through a section. The MX/enduro bars were swapped out for a set of Renthal vintage trials bars. The Preston Petty headlight was removed and a small trials number plate was installed. Finally the gearing was changed from the stock 12/42 to 11/50.
The end result of all these modifications doesn’t look too bad.
After riding a few events and riding around on a friends 350 Sherpa-T I came to the conclusion that the gearing was still way too tall. At first I searched around for a 350 Sherpa-T motor, but as close as I came was a 350 Alpina motor. Although I didn’t feel like handing over five Benjamin’s for the motor, plus some more cash for a larger rear sprocket and longer chain. However, being somewhat thrifty, I was able to locate the bottom end of a 250 Sherpa-T that fell into my budget (i.e. free). Not only was I able to salvage the gears, bit it also had the larger flywheel on the primary side. The complete swap only cost me a set of gaskets.
It’s actually a 1973 Bultaco M-98 (175) Alpina. While it was fairly complete, the cosmetics left something to be desired. Upon picking the bike up I found a lot of issues. The tank and seat were not correct. The exhaust pipe, coming fron the cylinder had rotted away. The front brake lever and cable were missing and the clutch and throttle cable were stretched. The tires were dry-rotted and RTV silicone oozed out from the cylinder to case joint. I had bought the bike in hopes of getting I ready to ride the 2003 ISDT Reunion Ride (Vintage Enduro).
I began stripping the bike down, but most important I wanted to make sure the engine was sound. It wasn’t!
Upon disassembling the top end I discovered the connecting rod piston pin journal was badly galled. This meant I needed to split the cases. Unfortunately, due to baby # 2 in the oven, funds for this project dried up quickly and most of the pieces ended in one corner or another of my garage and basement. The Reunion Ride came and went, but in the summer of ‘04 I started piecing it back together. Along the way I discovered many things. While the bike was originally built as a 175, somewhere along the way a 250 jug and piston was installed (the 175 and 250 share the same stroke). Being as thrifty (i.e. cheap) as possible I hunted down parts from every Bultaco supplier out there.
Finally, in October of ‘04, I got it running. My maiden ride was the 2004 SMOG (Spanish Motrocycle Owners Group) East Trail Ride.
First Ride Video
All I can say is riding a vintage bike, especially one with right-side shift/left-side brake, really makes you appreciate a modern bike!
After getting all the bugs worked out I rode the Alpina in two more SMOG rides and a couple vintage trail rides. Unfortunately having the shifter and rear brake on the “wrong” sides always through me for a loop. Most of the time it sat in my garage collecting dust. Then in 2007 I was convinced to participate in a vintage trial. Since the Alpina shares the same frame as the Bultaco Sherpa-T (trials model) it lends itself very well to a stand-up riding position. However it takes more than just mounting a set of trials tires to set-up an Alpina as a trials bike. So after my first miserable experience I went about making the Alpina into a Sherpina.
First I located the slimline tank/seat from a Sherpa-T. The tank required some fiberglass work, sealing so it would hold fuel and a rattle-can Earl Schieb. Meanwhile a friend made a new seat pan out of fiberglass, cut some foam and recovered it. The tank holds over a gallon less fuel and the smaller seat makes it easier to maneuver around to maintain your balance at low-speed. Next I installed a set of low-front fender mounts which aids in aiming the front tire while plonking through a section. The MX/enduro bars were swapped out for a set of Renthal vintage trials bars. The Preston Petty headlight was removed and a small trials number plate was installed. Finally the gearing was changed from the stock 12/42 to 11/50.
The end result of all these modifications doesn’t look too bad.
After riding a few events and riding around on a friends 350 Sherpa-T I came to the conclusion that the gearing was still way too tall. At first I searched around for a 350 Sherpa-T motor, but as close as I came was a 350 Alpina motor. Although I didn’t feel like handing over five Benjamin’s for the motor, plus some more cash for a larger rear sprocket and longer chain. However, being somewhat thrifty, I was able to locate the bottom end of a 250 Sherpa-T that fell into my budget (i.e. free). Not only was I able to salvage the gears, bit it also had the larger flywheel on the primary side. The complete swap only cost me a set of gaskets.
