AMF Harley-Davidson SST250

Hi,

I owned a very tatty 1976 Harley-Davidson SST250 from July 1980 (when I turned 18) to May 1982. I moved up from a Suzuki TS125 after seeing AMF Harley-Davidson SST 250s when visiting the IOM (Isle of Man) TT races in 1980. They were pretty bikes with a pulsing 2-stroke rumble and that magical name emblazoned across the tank. They were very quick off the mark thanks to low gearing and as 'used' as it was, it still stood out how it stood out in the lines of cookie cutter Japanese models parked at the shopping center in Maidenhead.

The SST250s were the final evolution of the SS/SX 250s before being taken over by Cagiva in '78/79.  They certainly had their problems, many of which were purely the result of minimal attention to quality. Cables had severe lube / quality issues, which the heavy motocross clutch continually broke (I broke 2 cables before getting fed up and adapting a drilled bolt / nut stop) and a throttle cable which continually stuck like some prehistoric cruise control. My 4 year old (!)  SST 250 vibrated like crazy because there insulators were shot and the crank was out of balance - by the time you hit 80 mph the bike was vibrating so much, your teeth would hurt and your vision was so blurry you could hardly see the road.

Each high speed ride (regardless of how long it was) was concluded with a quick walk around to check what had fallen off that particular trip. Bulbs blew constantly, if not because of vibration, then due to the diabolically crappy electrics. The engine itself was a pretty hot alloy cylinder w/ chrome bore arrangement w/ a colour-coded piston sealing perfectly round once up to temp, but for any bikes showing age / wear / neglect a rebore was not possible and rechroming damn near unaffordable). The OEM piston / connecting rod consisted of a fairly spindly needle roller bearing. The poor supplier quality extended to the kick-start gear, which quickly stripped all teeth after a year or two of enthusiastic starting - the same kick-start was integral to an idler for the Mikuni oil pump regulating flow of 2 stroke from the in-frame oil tank. On the  times I was gleefully winding out the throttle, I was also starving the block / piston of oil-mix requirements for high rev operation. Luckily as the SST was so hard to hold on to, I kept the 'high speed' runs pretty short, which allowed flow to adjust to the lower rev rate pretty quickly and the block to cool. One evening I was gritting my teeth and hanging on while passing a semi-trailer at 75 MPH  when suddenly the bike went all quiet as the piston / block seized, locking the back wheel solid and sliding the bike slid sideways across the truck lane (behind the truck, thank goodness). It then  dumped me unceremoniously into the soft grass next to the A40. With nothing more hurt than my pride. I let the Harley cool and tried to start it again. It started OK enough and I proceeded on my way.

The bike could be bump-started by turning ignition on, kicking it into neutral, waiting for a break in the traffic and pushing it up the road as fast as you could. Then you would jump side-saddle style on to the seat while kicking the gearshift up into second, at which point if all went to plan, the bike would fire straight away and you could pull in the clutch, rev it, throw your leg over it and blast away. This happened about 50% of the time. The other 50% of the time you would bang it into 2nd gear just before TDC, where it would still have enough compression left to lock the rear wheel without firing. When this happened and because you were sitting side saddle the bike would stop and tip to the right, dumping you on your @$$ into the street in front of oncoming traffic (and of course, any hot girls who happened to be around at the time).

Other noteworthy issues were a side stand that kept collapsing and having to be rewelded, wicked frame flex when cornering (although that might have been due to extremely worn swing-arm bearings), an ignition switch that would let water in and not out and would only work with 1 particular key turned to exactly to the 1 o'clock position. The light switches looked like they were raided from a Puch Maxi. The cylinder head had 2 large bolts - one for the plug and another plug blanked off. One time when the kick-start was fixed, I gave it a good kick, it fired and the 2nd bolt shot up into my leg resulting in much hopping around the garage. The entire tail light assy fell off on my way home from night-school in Maidenhead. The Tach bounced all around the dial and the speedo apple-cored around the front wheel resulting in an overly expensive replacement.

The forks on my SST were beautiful Marzocchis, but after just 4 years the alloy was pitted and the chrome was already peeling badly. Front brake was a Brembo disc affair, but I wore out the disc and caliper (pads were bonded to the pistons - WTF) and could not afford a new one so I tried not to use the front brakes and relied on the rear brake and engine braking. AMF HD in their wisdom used dissimilar metals for the rear quick release hub and the brake cam so after a period of time they would seize, which did not help braking any. I tried regularly cleaning the  brake cam to retain what little braking I had. The rear brake shoes were meaty enough, but I did have one time when the shoe spring broke and I ran out of brakes, so that involved having to pull it apart again.

Paint finish was diabolical. My bike had just topcoat, no primer, which I found that out when I dropped brake fluid on the front guard. But the colours offered were very nice for the mid-70s (my SST 250 was a beautiful metallic bronze). In 1981 my brother and I decided to rebuild and repaint the bike metallic blue, complete with a new set of Harley decals for the tank. The bike got a new big end but the block was reused (and sounded like it). I finally gave the bike to my brother after I went back to Australia in 1982. He stuffed it into the side of a Morris Marina 3 months later, crushing the forks and it was relegated to the bottom of my parents garden....

Yet, in spite of all the above, the fear factor was part of the thrill and wondering whether it was going to blow up at any moment added a certain element of adventure when making a trip anywhere further afield. With its ahead-of-its-time flat-tracker styling, burbling down the high street in 5th made for a great pose. To be perfectly honest, with my very limited wrenching skills (translation: non-existent), many of these issues were down to a sorely neglected bike. Had the forks /swingarm / engine / shock all been in good condition, or fitted with aftermarket items (relegating the original junk to the trash-can where it belonged), it would have been a half decent bike. To be honest, I would not want another metallic bronze SGF471R - I did not have the money / knowledge or patience to fix / iron out the faults and past abuse. But now, nostalgia has kicked in and I have a much better idea of what can be done. I currently have a complete SST250, a non-running SS250, a stack of SST250 parts sourced from Ebay Italia and a plan to make them the bikes they could, or rather, should have been. Let's see where we end up.

Ian B.

 

Hi Chris,

Thanks for your reply. Glad you enjoyed the write up. I will certainly add more pics and info in the Project area for anyone who is interested. The paint work is on its way back now and should be here in a week or two  :Thumbs_up:

Cheers,

Ian B.

P.S.

Q: Whats the difference between an enthusiast and a masochist?
A:  I ride a Harley lightweight, so I wouldn't know  .

 

Hi mboddy,

You've been on the Dark Side for quite a while then already  :Thumbs_up:. Did you sell the SX175 or did it fall to pieces?

Cheers,

Ian B.

 

Interesting link on a '76 US-model AMF-HD SS250.

1976 AMF Harley Davidson / Aermacchi SS 250

Ian B.