Suzuki GSR Slip On Fitting Woes

[jrich123]

Afternoon All,
I purchased a used Akrapovic GP Series Megaphone slip on off fleabay for my GSR 750 2014 the other day.

On attempting to fit at the weekend the inlet pipe diameter on the slip on is some 2-4 mm too small with standard exhaust gasket.

However the slip on fits onto the cat pipe quite easily with no exhaust gasket.

I did fit the slip on pipe (albeit temporarily to the cat pipe), started her up all worked fine but as predicted there was a small leak as no gasket fitted.

Now my questions are...
Should there be a "slim line" (smaller) version of the exhaust gasket?
Or
Do I have to take the slip on can to an exhaust fabricator to get them to expand the pipe at the joint end (I guess this is possible with this titanium can?)?

I have refitted the standard at present and all is fine.

Any advice on the above is greatfully received.

Thanks,

[Jazoli]

Just use a bit of clear silicone sealant to seal the gap or a bit of exhaust paste, most slip on's don't use the standard gasket in my experience and just clamp onto the existing exhaust.

[cmaguire]

There is an installation guide on the Akrapovic website.
No mention of gaskets and clamp at cat pipe and hanger both 22Nm.

With the increase in noise they probably aren't too bothered by a slight leak at the join.
I would use exhaust paste, not keen on the silicon suggestion due to the heat.
If it is a real piss-fit then you could use aluminium foil to wrap around for a makeshift gasket.

[jrich123]

Cheers guys much appreciated.

On searching for silicone gasket (I too was dubious at first!) it seems this product is widely recommended in US circles...

https://www.ebay.co.uk/itm/RTV-Silicone-Permatex-U...

Any experience of using this stuff?

Must admit the home made foil gasket does not sound like a bad idea! Cheap and could work

[cmaguire]

jrich123 said:

Cheers guys much appreciated.

On searching for silicone gasket (I too was dubious at first!) it seems this product is widely recommended in US circles...

https://www.ebay.co.uk/itm/RTV-Silicone-Permatex-U...

Any experience of using this stuff?

Must admit the home made foil gasket does not sound like a bad idea! Cheap and could work

Looks OK, you could also use a bead of that or exhaust paste on the foil as you wrap it to create a better gasket if the gap is too big to get a secure fix without a gasket of some sort.

[CAPP0]

I've used the silicon seal on a V8 car (twice, once each side ), I was sceptical too when I first heard about it but if you search eBay there are loads of people selling high-temp silicon exhaust sealant. Works, too.

[Mr2Mike]

CAPP0 said:

I've used the silicon seal on a V8 car (twice, once each side ), I was sceptical too when I first heard about it but if you search eBay there are loads of people selling high-temp silicon exhaust sealant. Works, too.

Though not a good idea if the system uses an oxygen sensor.

[Prof Prolapse]

My CBR exhaust is about 10% Firegum. Doesn't Leak mind... Well not there least...

[Moulder]

Is the gasket a silver hoop? If so you can usually peel these like an onion, either the remaining layer or the first one you peel off should be able to be used as a gasket with the new pipe.

[jrich123]

Thanks All, really appreciate the comments and suggestions.

I guess there is an oxygen sensor in the system but the sensor (if there is one) sits well before the join between the slip on and the cat pipe. So logic would tell me the silicone sealant would not affect the oxygen readings – please correct if wrong though!

This is the gasket in question, I did buy a new one thinking the Akrapovic would require it but I used the new gasket to refit the standard slip on back on (I discarded the original one on there – I know I should have kept it!) Looks like you can peel the layers as per the area circled in red..



Anyone else peeled back an original gasket before or would you stick with the silicone sealant? Must admit I am inclined to try the silicone sealant first with this stuff below, anyone used it before?

[cmaguire]

Those graphite standard gaskets are mesh reinforced and the graphite falls to bits if you bend it.

I don't fancy your chances.

If you were to use foil to make a gasket you can use a paintbrush to apply a thin film of your silicon or exhaust paste to it.as you wrap.

[Moulder]

Peel it, sounds like you don't need it anyway if it does come apart. A vertical cut through the first layer and it should peel away, then repeat until the right size or use one of the peelings.

[CAPP0]

Mr2Mike said:

CAPP0 said:

I've used the silicon seal on a V8 car (twice, once each side ), I was sceptical too when I first heard about it but if you search eBay there are loads of people selling high-temp silicon exhaust sealant. Works, too.

Though not a good idea if the system uses an oxygen sensor.

jrich123 said:

I guess there is an oxygen sensor in the system but the sensor (if there is one) sits well before the join between the slip on and the cat pipe. So logic would tell me the silicone sealant would not affect the oxygen readings – please correct if wrong though!

Provided you're not smearing silicon all over the o2 sensor (and why would you/how could you?) then I can't see any issue with that at all, unless Mike knows something we don't?

[Mr2Mike]

CAPP0 said:

Provided you're not smearing silicon all over the o2 sensor (and why would you/how could you?) then I can't see any issue with that at all, unless Mike knows something we don't?

Standard silicone sealer leaches out silicon which coats O2 sensors and stops them working, it doesn't take much to do this. In an exhaust you get reversion pulses with every engine cycle, so even if mounted downstream of the sensor it's still possible to get contamination. If you have to use silicone sealer use the stuff that is marked as "sensor safe" e.g. Permatex Ultra Copper RTV.

[CAPP0]

Mr2Mike said:

CAPP0 said:

Provided you're not smearing silicon all over the o2 sensor (and why would you/how could you?) then I can't see any issue with that at all, unless Mike knows something we don't?

Standard silicone sealer leaches out silicon which coats O2 sensors and stops them working, it doesn't take much to do this. In an exhaust you get reversion pulses with every engine cycle, so even if mounted downstream of the sensor it's still possible to get contamination. If you have to use silicone sealer use the stuff that is marked as "sensor safe" e.g. Permatex Ultra Copper RTV.

Well, every day's a school day! Thanks.

I only used it on a carbed Rover V8 where there were no lambda sensors, although I have another project on the go currently which DOES have sensors, so I'll bear this in mind.

[jrich123]

Morning All – Thought I’d give an update on this.

RTV copper silicone sealant seemed to work a treat so I’d recommend that.

After running Akrapovic megaphone for a few days the sounds is quite addictive but when you just want to cruise along it can become a little tiresome with the popping on over run – but generally happy with it.

However there seems to be a slight issue from what I’ve noticed. Cold idle on start up seems very lumpy oscillating between 1-2k for until I take it for a quick spin then settling down to normal idle around 1.5k, also when the bike is warm on start up there seems to be a lumpy idle until I give it a few revs.

With the standard exhaust the above does not happen… I refitted the standard slip on and it was back to normal.

Also the so called “herky jerky” (as our state side friends call it) seems more pronounced and noticable with the Akrapovic can… maybe its my imagination!

If you’ve not heard of this herky jerky before here is the link to it https://www.gixxer.com/forums/236-05-06-gsx-r1000/...

My questions are, what could be the cause of the idle issues and pronounced “herky jerky”?
Do these aftermarket cans effect the low speed running due the little to no back pressure they produce?

I did a search but cannot appear to find any related topics

Cheers for your help and advice!

[CoolHands]

Probably running too lean as all engines do these days. Needs a ecu retune or flash or whatever.

[jrich123]

OK cheers Coolhands.

Could well be the cause, was planning to change the plugs at some point so the plug condition will be the tell tale sign of lean running.

Also I forgot to mention the fuel ecomomy was significantly better with the Akrapovic can, which surprised me no end - however this could be the symptom of lean(er) running?