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Discussion Starter · #1 ·
A strange thing happened to me on the way home.

I was sitting at a set of red traffic lights for about thirty seconds with a taxi parked behind me. The lights shanged to green, I grabbed my throttle and gave it the slightest movement to accelerate off and I heard a loud bang. I have been reading these forums for years so I know that the Vee can sometimes blow off a "boot" ("throttle body" boot?) when the bike backfires so that was the first thought I had.

Then I checked my rear view mirror as i pulled away and noticed that the taxi behind me had its hazard lights on and it was not moving. So it made me wonder if the taxi was responsible for the noise, or if my bike had made the bang and the taxi driver thought it had come from his car, or even if perhaps the taxi had been rear ended.

The other thing is that the last time I filled my fuel tank it was with 91 octane, rather than my usual 95 octane (Aussie octane). So now I really dont know where i stand.

I rode home in the dark and the bike was running very well. I was pretty paranoid at this point and I have only ridden the bike for a month so I don't know if there was any difference in the way the bike was running. It didn't feel like it had lost any power and it idled fine. There were no obvious hiccups or anything like that. When I got home I used a torch to look at the front boot and it looked like it was still pushed all the way onto it's...thingo (as far as it could possibly go). I couldnt get a good view of the rear one.

I guess I should ask some questions:
  1. If you've blown off a boot, which one is it that normally comes off?
  2. If you've blown off a boot, what are the symptoms? Is it really obvious with rough running, power loss, no idling or whatever? My bike remains perfectly rideable.
  3. Seeing as my bike is running OK, is it safe for me to ride to work till the weekend before pulling the bike apart to get a good look at the cylinders?
  4. What am I going to have to do to get a clear view of the engine?

I'm really hoping that it was the taxi getting rear-ended that I heard. I wear earplugs so I can't be sure where the bang came from, and the confluence of events has left me unsure until I can see the engine with my own eyes which I wont be able to do till the weekend. If the car behind me had kept driving, I would have assumed the noise came from my bike. If i had refueled my bike with the same fuel as usual, I would be less confident that my bike had backfired. If I hadn't been in the process of adjusting my throttle when the bang happend, I would assume the noise came from somewhere else.

Any thoughts or opinions or suggestions ?
 

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G'Day Strange Dog, I blew the front boot once about 1k from home and I kenw something was wrong. I thought I had killed the bike or something as the noise was horrendous. It would not idle,when it did run sounded like a chaff cutter. I struggled home and after a coffee and a think I ripped of the tank and airbox and found the boot off the front throttle body. I removed the rubber boot from the air box and tightened the clamp onto the throttle body then fed the boot back into the airbox as I replaced it. Has never happened again. By the sounds of things I would say it was the taxi not your bike that made the noise.

Cheers
 

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Discussion Starter · #3 ·
Thanks Vman, thats put my mind at rest. I depend on my bike to get to work and the thought that I had encountered my first mechanical problem after 5 weeks of ownership was feeling pretty depressing.
My bike is running fine, so I guess I am being paranoid. I will check it out on the weekend. Guess I've gotta learn how to get at the engine eventually :)
 

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I blew off a boot last year on the Vermont group ride. In my case the rear one, and you can tell by the explosion coming from your crotch. There was some rough running, but it would idle (a little roughly) and run OK. Decceleration with closed throttle brought on lots of small and medium backfires through the airbox.

Getting to the rear boot is simple. Seat and sidepanels off. Take off some of the trim around the tank at the bars. Undo fairing attachments to the tank. Undo the tank bolts, and prop the tank up. Rear boot is right there. I cleaned off the mounting flange on the throttle body, loosened the clamp on the boot, and it popped back into place. Tightened it up, and reversed the above. Took perhaps 20 minutes start to finish.
 

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Discussion Starter · #5 ·
I blew off a boot last year on the Vermont group ride.
Any idea what caused it? crappy fuel?

you can tell by the explosion coming from your crotch.
So its something you feel as much as hear ?

There was some rough running, but it would idle (a little roughly) and run OK. Decceleration with closed throttle brought on lots of small and medium backfires through the airbox.
Sounds like it impacts performance in a way that is impossible to not notice?

Took perhaps 20 minutes start to finish.
Sounds like my kind of job :)
 

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I blew a boot off doing a TBS (turning the wrong way) hell of a noise, I'm sure your bike's ok, not sure about the taxi though.
 

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"Any idea what caused it? crappy fuel?"

No idea. Really not a clue


"So its something you feel as much as hear ?"

Exactly


"Sounds like it impacts performance in a way that is impossible to not notice?"

The bike still performed well. I wouldn't say it impacted performance much, if at all, but it is impossible not to notice.
QUOTE]
 

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blown boot

I got half way through your post and kept thinking that the taxi had blown a battery. I've only been around one that blew but it sounded like a bomb went off.
 

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I've blown my trailing boot off twice. The bike looses a cylinder and sounds like it. I learned that you can safety wire the boots to the engine block.
 
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