Octane, 87 ain't cutting it!

I use a good source that fuels my race bikes too. I'll check to see if they just got a new winter blend or something. The 93 seems to have just about eliminated it for now.

Describe the sound and RPMs if you can please.

Mine sounds like a very light, tinny sound. Kinda hard to describe, the sound of hot metal being hit by cold liquid drops maybe, like a sizzle.

I have a feeling my noises might be the cat expanding or overheating at those RPMs now. Looking into that further.

I didn't either till the other day. I've been around the block with this before too, I'm not exactly sure what I'm hearing but it fits the right conditions for now.

The tinny 300 engine will not sound like my tuned 32v Mach 1 when it gets a belly of crap gas.

New theory for now, cat delete and the noise is totally gone. I can't get it to do it at all now where even with 93 octane it would happen slightly around 4500 RPM.

I'll report back if it starts again but i think that was the culprit and probably not a real problem, just a noise the bike will make. I've read these are very lean at lower RPMs, that may cause it to overheat under load.

Turns out the cat delete wasn't the solution. I noticed the noise again within days. I started to think it was a vibration off the fairings till a new tuner ended the noise completely.

If you are getting a metallic sizzle sound, like light wire brushing against aluminum foil is the best I can describe it, go to higher octane (which wasn't enough for me) or get a tune. That 4-5k RPM zone must be really messed up stock.

Well, I am not going to buy $17 a galllon race fuel. I don't even do that for my MX bikes and they are much higher strung that the 300!

We have what we have here in NJ. Winter brings some really bad oxygenated slurry to the pumps. MPGs drop across the boards.

I'll keep up with the higher octane and hopefully nobody else has the same issues.

Bah! I had it tinkle a few times again last night, and then I remembered I put fuel in from my MX bike jug which "should" be premium but somebody in the family must have filled it with who knows what. Not as obvious as before but now occasional undew load and closer to the 5k mark on the tach. I'll run it down and refill and see if it is still there, GRRRRRRRRRRRRRR!