Thumper Club Forum

Club House => Chatter => Topic started by: manxie on October 06, 2019, 04:05:18 PM

Title: Bullet Zorst
Post by: manxie on October 06, 2019, 04:05:18 PM

I bought a second hand (done 50 miles) hitch ocks silencer of a 2017 Bullet. Fitted it to my 2012 bike, straight swap. On initial start up it struggled to fire but seems ok now? It does backfire on the over-run quiet loudly.

Now, looking at their website the silencer for the `17 bike is different to the earlier model (part numbers)? It is only the rear silencer I`ve swapped so not disturbed and sensors. Both bikes EFI models. Any ideas? 

Thanks fellas.

Title: Re: Bullet Zorst
Post by: themoudie on October 06, 2019, 04:46:05 PM

Aye Steve,

Air leak into the exhaust system at the join between the silencer and exhaust pipe. Sucking air (oxygen) in on the overun/closed throttle causing unburnt fuel to ignite in the silencer. Change of back pressure  may also initially confuse the EFI. Use some exhaust assembly paste to ensure a good seal if you haven't done so already. If a leak still persists, then a sleeve manufactured from a tin can, exhaust assembly paste and the use of a jubilee clamp, instead of an exhaust clamp might help. Exhaust clamps do not always give a 360 degree all round pressure on the joint and can allow a leak through the expansion slit/s on the silencer, if they align with the gap in the exhaust clamp.

However, this may be all ***** :-[ as I have never had to deal with EFI's!  ;)

I am sure that the sage's will be along to give chapter and verse on 'Thunder Guts'.  ;)

Regards, Bill

Title: Re: Bullet Zorst
Post by: manxie on October 06, 2019, 06:58:34 PM

Thanks Bill. I used exhaust paste but maybe exhaust clamp not right? I`ll give it another dose of looking at  ;) It sounds a lot better though. Hopefully you`re right about the ECU adjusting to the different exhaust pressure, it does seem to be a bit better now  ;D

Yet again, thank you Bill for your input, it is appreciated.

Cheers, Steve.

Title: Re: Bullet Zorst
Post by: Propellor on October 06, 2019, 07:26:43 PM

Most likely air getting in as Bill said. Probably at the pipe to silencer joint but don't discount the head joint either. I'm no expert on fuel injection either but one would assume a leak after the lambda sensor wouldn't be an issue to the fuelling but a leak before the sensor might.

Title: Re: Bullet Zorst
Post by: manxie on October 06, 2019, 07:41:28 PM

Quote from: Propellor on October 06, 2019, 07:26:43 PM

Most likely air getting in as Bill said. Probably at the pipe to silencer joint but don't discount the head joint either. I'm no expert on fuel injection either but one would assume a leak after the lambda sensor wouldn't be an issue to the fuelling but a leak before the sensor might.

Thanks Prop. It was fine until I changed silencer so the only joint disturbed was after the lambda sensor. It`s not a major issue and is still an ace bike  :D just needs a little tweek  ;)

Thanks, Steve.

Title: Re: Bullet Zorst
Post by: xbally on October 07, 2019, 06:52:12 PM

I seem to recall they all do that if I remember correctly-used to have an 09 EFI which i kitted out with correct *itchcock's exhaust and silencer...

Title: Re: Bullet Zorst
Post by: manxie on October 07, 2019, 11:01:13 PM

Quote from: xbally on October 07, 2019, 06:52:12 PM

I seem to recall they all do that if I remember correctly-used to have an 09 EFI which i kitted out with correct *itch*******'s exhaust and silencer...

Thanks for that. I had a nice little run out on it tonight just as darkness fell. I did about 20mls and I think it only backfired four time  ;) Got followed by the police through town, I was just over tickover to keep the noise down …. they didn`t stop me  ;D ;D