# Fuel Filler Cap V7 850
**URL:** https://forum.motoguzziclub.co.uk/t/fuel-filler-cap-v7-850/24108
**Category:** V7, V9 & V7 850 (2007 onwards)
**Created:** [15 June 2026 16:55 UTC](https://forum.motoguzziclub.co.uk/t/fuel-filler-cap-v7-850/24108 "2026-06-15T16:55:45Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@twinpot\_shocker](https://forum.motoguzziclub.co.uk/u/twinpot_shocker)
#### Post date: [15 June 2026 16:55 UTC](https://forum.motoguzziclub.co.uk/t/fuel-filler-cap-v7-850/24108/1 "2026-06-15T16:55:46Z")
Hi, the fuel cap will not unlock on my V7 850. The key goes fully into the barrel and turns through 45 degrees but the lock will not disengage and allow me to unscrew the cap. Any ideas would be welcome. I have tried WD40 and penetrating oil but with no joy. any thoughts would be welcomed. Thanks.
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### Author:  [@PAHAWK-74](https://forum.motoguzziclub.co.uk/u/PAHAWK-74)
#### Post date: [17 June 2026 12:01 UTC](https://forum.motoguzziclub.co.uk/t/fuel-filler-cap-v7-850/24108/2 "2026-06-17T12:01:56Z")
Probably not helpful, but I have the opposite issue! I have a 2024 v7 Special, mine becomes loose and needs lots of twists and downwards pressure to keep it from undoing! P.S. just back from dealer after new ECU fitted after engine cutting out.
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### Author:  [@PAHAWK-74](https://forum.motoguzziclub.co.uk/u/PAHAWK-74)
#### Post date: [17 June 2026 19:12 UTC](https://forum.motoguzziclub.co.uk/t/fuel-filler-cap-v7-850/24108/3 "2026-06-17T19:12:23Z")
Just seen a youtube video on this problem. The owner says to press down hard on the cap whilst turning it. Hope this helps.
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### Author:  [@twinpot\_shocker](https://forum.motoguzziclub.co.uk/u/twinpot_shocker)
#### Post date: [17 June 2026 20:20 UTC](https://forum.motoguzziclub.co.uk/t/fuel-filler-cap-v7-850/24108/4 "2026-06-17T20:20:38Z")
Thanks that’s helpful. Will give it a go.
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### Author:  [@twinpot\_shocker](https://forum.motoguzziclub.co.uk/u/twinpot_shocker)
#### Post date: [18 June 2026 12:29 UTC](https://forum.motoguzziclub.co.uk/t/fuel-filler-cap-v7-850/24108/5 "2026-06-18T12:29:59Z")
Well, your suggestion worked 😀. I pressed down very hard on both the cap and the lock barrel turned the key, kept pressing on the cap and turned the key was there a release of air from a vacuum that had formed and hey presto!. Cheers
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### Author:  [@sidthedid](https://forum.motoguzziclub.co.uk/u/sidthedid)
#### Post date: [18 June 2026 12:40 UTC](https://forum.motoguzziclub.co.uk/t/fuel-filler-cap-v7-850/24108/6 "2026-06-18T12:40:40Z")
my v85tt wouldnt start one day, I had just ridden 60 miles or so and stopped to take a photo, so engine was fully warmed up and no reason for it not starting. as well as trying to start with the button I tried rolling down the hill, no joy.
although I was sure it had plenty of fuel, I opened the fuel cap, not that you can see anything due to design of tank but I was at a loss what else to do.
there was a loud sucking noise as I opened it, I closed it and bike started first time.
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### Author:  [@PAHAWK-74](https://forum.motoguzziclub.co.uk/u/PAHAWK-74)
#### Post date: [26 June 2026 11:11 UTC](https://forum.motoguzziclub.co.uk/t/fuel-filler-cap-v7-850/24108/7 "2026-06-26T11:11:13Z")
Glad it worked for you! I had the vacuum issue, now since new ECU , the vacuum has mostly gone, just petrol cap is much less tight
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### Author:  [@Mike\_H](https://forum.motoguzziclub.co.uk/u/Mike_H)
#### Post date: [26 June 2026 13:28 UTC](https://forum.motoguzziclub.co.uk/t/fuel-filler-cap-v7-850/24108/8 "2026-06-26T13:28:17Z")
You could do the ‘EVAP delete’ so that the tank vents to atmosphere, then there won’t be any tank pressure differential. 🙂
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### Author:  [@twinpot\_shocker](https://forum.motoguzziclub.co.uk/u/twinpot_shocker)
#### Post date: [26 June 2026 14:54 UTC](https://forum.motoguzziclub.co.uk/t/fuel-filler-cap-v7-850/24108/9 "2026-06-26T14:54:04Z")
I’ve now found out what an EVAP delete is so thanks, I will be following up 👍