Strange noise after sh150i heats up.

[seanstr26m]

Ok I drive my scooter to work normally 9.1 miles there and 9.1 miles back. Normally no faster than 40mph.

However, periodically, I have to get on the highway and do 55-65 mph. Lately I can only get to 62 mph (not the problem, but may be related), and there is this weird rattle that is rhythmic. It only happens if it's driven hard/fast or if it gets hot, very hot, not the engine, that's status in normally operating temperatures. I live in St Louis, MO. It's been 100 or more lately often.

Side note, just replaced belt, gear oil, oil change, air filter cleaned (K&N), spark plug, clutch and spring assembly checked, and replaced rollers all but the rollers were OEM. Originally the rollers were OEM too but the noise came back so why not change back to the sliders?

Yesterday I drove to work, quietly. Drive on highway, tried to keep it under 60mph and it was also quietly.

Only the way back, loud. It was slightly warmer, and steamier, and for just a few seconds I had to take off quickly. I normally don't do this.

I spoke to my father ex mechanic with Chevy, said, muffler could do it, but since it's fuel injected, that could do it also, and that the computer could be the problem.

Any thoughts would be great.

[boiski]

I have few friends with same strange rattle noise (150&300). Mine 150 make it also usually when the engine is hot and while I'm accelerating over 30-40mph or ride/accelerate at high rpms on a slope. But I have to mention that my belt, rollers and sliders are worn.

Is it possible to be a engine problem, worn bearing?

[TommyXP]

I notice major differences too in temperature/humidity extremes, and like me the bikes seem to prefer cool/cold....
I'd be a little patient to notice if the symptoms persist under more 'normal' operating conditions before I started chasing-my-tail around some infinity variable computer parameters or I might just be looking for an excuse not to be tinkering with the bike under the blazing, merciless summer-Sun and hope the sensations the bike is giving me evaporate with more moderate atmospheres...
Every component, material, 'thought' is effected by the increased frequency of Heat and the imagination-less computer might be busy chasing some hard to define pre-determined 'normal'.....maybe.
I wish you Luck.

[seanstr26m]

I was thinking that heat was the culprit also but it was cooler and nose still there and louder. I've gotten it to reproduce it on the stand now. It's the muffler or the rear wheel bearing, or the gears for the rear. I'm leaning towards the muffler or the wheel bearing however when I shut off the bike and just spin wheel no noticeable feelings or noise from tire. Then, if it's in the area behind the spring where gearing is located, crap! I would still think I would feel that. I think it's baffling that's come loose. I'll bang on the muffler tomorrow morning.

[seanstr26m]

In the shop. I gave up. Too many noises. I'll update as they update me.

[seanstr26m]

They cannot find the problem. I cannot get them to test drive when I get off work. Tomorrow I'll call them, see if the guy can test drive it at 5pm . So he can hear the noise. I'll stick him on the scooter with me.

[TommyXP]

Good luck with the stealership......They don't have two minutes to take it for a spin because they are all busy working on your bill.....
BTW, how many miles are on your SH?

[seanstr26m]

17000 miles

[TommyXP]

One of mine has the same mileage and I hear rattles too! Some times when I am feeling good they seem to go away. I hope we are both just hearing 'normal' things......

[seanstr26m]

When it's light rattle noise, I just listen. This is getting loud after 20 mins on highway. I got it back the rim has some thing on the inside that assigns the tire. I didn't know I was doing it wrong. He corrected that. Find nothing else. Put back my original rollers and the replacement rubber gasket for belt cover back on.

On the way home from shop it was back, the noise.

So I called him back and he wants to replace everything. Variator, clutch, etc.

I didn't like this idea. So I called my dad and asked for his mechanic stethoscope. Tried to reproduce the noise. I couldn't. So. I wait