Manx Tank / Monza Cap


Having just fitted the manx tank on friday I had a good run to work and back today, approx 15 mile each way. I notice that on hard acceleration at around 4000rpm, and more noticeably rapid deceleration/over run, the Monza Fuel Cap makes a rattleing sound.

There is no traditional breather pipe on the Manx, as found on the thrux/bonnie tank, the breather is incorporated into the Monza cap. When opened, under the flip cap is a rubber seal, below this is a metal disk held in place with an adjustable nut. In the metal disc is a small hole which acts as the vent.

Any Ideas what the sound is caused by? Is it normal?

I'm guessing the nut could be adjusted to eliminate it or should it be left to make the sound if it's normal? There doesn't appear to be any venting issues as she pulled right up to the tonne today with ease.


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I have some bad news for you.I checked with my tank guy,and he said your tank is ruined,and it won't be a warrenty thing because it's something you did.(They don't just rattle.)

So,since I feel bad for you,and that tank is now considered toxic waste,I will take it off your hands,at no charge to you,and dispose of it properly.

PM me for shipping instructions.

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TT Racer
it's clearly to dangerous to ship that across our great country, I'm on the east coast and would willingly sacrifice myself in the attempt to dispose of it properly.

other than that I hope you get it fixed.


That's very kind of you! but I kinda like the rattle! it sounds like an Artillery Barrage or turbo kicking in!


The rattle turned out to be the wiring loom touching the tank due to the tight fit. Uncliped loom and re positioned it below the main frame and rattle gone!