Took the ct3 for a spin.  Hit full throttle, reaching 50-ish during a very slight incline and felt a quick shudder. Being only half smart, I kept going at speed but soon I noticed that the engine revved quicker and felt like it had less resistance on it.  The throttle felt loose for half a second and then back to normal. The crankshaft continued to spin easier. I slowed down for a red light and the bike started to shake and vibrate. It felt horrible.   At the green, I pulled off into a parking lot to inspect for carnage. The front engine mount bolt was gone. Not having anyone from whom to ask for assistance, I rode the four miles home very gingerly. 

Once home, I installed the original pitted engine mount bolt and drove around the neighborhood to see if there was any lingering issues.  The only thing I noticed was that I didn't have to up-shift so quickly because the engine was so much smoother. Before I guess I had to shift around 4k rpm going from 1-2-3 because it felt so rough. In 4th and 5th the engine was relatively smooth at high rpm.  The engine now feels very smooth at all revs in all gears. It reminded me of a test drive I took of a Mazda with a rotary engine.  At the end of this test run I hit a stretch of road that is a connects two highways. On a flat section, I hit 65 mph as indicated by a gps phone app and 66 on a slight incline downwards.  The bike felt much smoother at top speed than on previous runs.  I am utterly baffled by all of this.

Any ideas as to what could have changed?   I intend to split crankcase and inspect the engine over the winter.

That is one of the problems with never having previous experienced a bike in good condition before and not having someone local who can tell you that something doesn't sound or feel right. I didn't know the bike could be so much more fun to spin up and tool around. I hope I didn't ruin it.

thanks for reading.
Rob






 

Bdee I have a Ct1c basically the same thing happened when my son was riding vibrating and he said it didn’t run that good we had a couple of engine mounts loose and tighten them up he said it runs much better and no vibration. Big mystery just glad it was a easy fix. 

Great job finding and fixing it!  I've seen bikes ridden until the mount holes were wallowed out and frame cracked from many miles of riding with loose or broken mounting bolts.

Carb. shaking to the point of aerating the fuel(going lean WOT and rich at idle.)

cliff

My CT1B had been riden like that at some point in its life. Both bottom loops were cracked on the welds and the front mount elongated on the frame and motor.