Tremelune
Been Around the Block
My bike is a damn-near-stock 1973 CL350K5. I was out for my first real ride on the thing. I bought it a year or two ago when the original owner put it away for 25 years and then died, and mostly just puttered around Brooklyn until I could get it sorted. It has 8,000 miles.
It was shod with a new set of professionally mounted/balanced Michelin Pilot Activs in 3.25x19 and 4.00x18. Stock size is 3.00x19 and 3.50x18, respectively. Everything else was, as far as I can tell, stock.
I was riding on a clear day. The bike was behaving flawlessly. No shakes, shimmies, or shifts that I could detect. It felt planted (though still not a fan of the bumps). I was on a dry road traveling in a straight line. I was approaching an indicated 85 mph when the front end began to wobble. I let off the gas as smoothly as I could in the hopes of slowly, calmly decelerating to a speed that had proven more stable. The oscillation increased in magnitude. I then tried to roll on the gas (again, calmly and smoothly) in the hopes that getting the bike neutral would ease things down. The wobble continued to get worse until it was eventually a full-on tank slapper and the front tucked. This was over maybe five seconds or so.
Things I think:
- Even 40 years ago, this bike was designed to recover from front end oscillations at speeds it was not capable of achieving in stock trim, even if the forks where compressed or disturbed.
- The rear tire was noticeably larger in diameter than stock (but I believe the overall change was less than 1" from eyeballing).
- The front tire was probably marginally larger in diameter than stock.
- It is common to put this tire size on these bikes, though I can't say I've seen any speed claims. The CB setup is much more common than the CL setup.
- It is a common mod to put on longer shocks to raise the rear of these bikes to quicken the handling a bit (my understanding being they are conservative in terms of rake/trail from the factory).
- I did not hit a bump or a groove that I am aware of.
Anyone have any ideas as to why this thing started shaking?
It was shod with a new set of professionally mounted/balanced Michelin Pilot Activs in 3.25x19 and 4.00x18. Stock size is 3.00x19 and 3.50x18, respectively. Everything else was, as far as I can tell, stock.
I was riding on a clear day. The bike was behaving flawlessly. No shakes, shimmies, or shifts that I could detect. It felt planted (though still not a fan of the bumps). I was on a dry road traveling in a straight line. I was approaching an indicated 85 mph when the front end began to wobble. I let off the gas as smoothly as I could in the hopes of slowly, calmly decelerating to a speed that had proven more stable. The oscillation increased in magnitude. I then tried to roll on the gas (again, calmly and smoothly) in the hopes that getting the bike neutral would ease things down. The wobble continued to get worse until it was eventually a full-on tank slapper and the front tucked. This was over maybe five seconds or so.
Things I think:
- Even 40 years ago, this bike was designed to recover from front end oscillations at speeds it was not capable of achieving in stock trim, even if the forks where compressed or disturbed.
- The rear tire was noticeably larger in diameter than stock (but I believe the overall change was less than 1" from eyeballing).
- The front tire was probably marginally larger in diameter than stock.
- It is common to put this tire size on these bikes, though I can't say I've seen any speed claims. The CB setup is much more common than the CL setup.
- It is a common mod to put on longer shocks to raise the rear of these bikes to quicken the handling a bit (my understanding being they are conservative in terms of rake/trail from the factory).
- I did not hit a bump or a groove that I am aware of.
Anyone have any ideas as to why this thing started shaking?
