I have just spent today replacing the cat with a Mivv on my Mutley. It saves an awful lot of weight, and sounds a bit fruity. I look forward to trying it out tomorrow. Fitting the Mivv exhaust system was quite easy, including putting the springs on. The difficult bit was taking the cat off, which was quite a struggle. The workshop manual fails to mention that the rear wheel has to be taken off - that becomes apparent only when the cat is nearly off and fouls the wheel. Then the wheel nut turned out to be a lot tighter than it was when I did it up - it broke my torque wrench (literally) so I had to rush out and buy a breaker bar. With an extension tube on the bar and my son helping, it eventually moved.
I fitted a LeoVince decat and didn't have to remove the rear wheel to extract the cat. None of the guides I read mentioned that either so I wonder if this was something specific to your bike? Nick
I am telling you that as I moved the catalyst box backwards, trying to disengage it from the front cylinder downpipe, it reached a point where it simply would not move any further backwards because it was hard up against the rear tyre. Once I had taken the rear wheel off, it became possible to move the cat a little further back, disengage it from the downpipe, and thus remove it from the bike. So when you say, "The rear wheel doesn't need removing to take the cat off" what do you mean by it? Please let me in on your secret.
I fitted the same decat pipe and a Mivv oval carbon can and did not have to remove the rear wheel, did however raise the suspension to max. ht. prior to removal
Pete, I suspect most people slackened the three nuts holding the front pipe on, rather than remove the wheel. That allows the cat to drop down a bit and therefore clear the rear tyre.
Fitted a Mivv on mine - just had to undo the 3 bolts on the header pipe so that the cat could wriggle back forward and down.
As the guys said, remove 3 nuts from front manifold, springs from rear manifold and cat drops down, no problem.
Many thanks for all the helpful posts. The sequence of steps for removing the cat as given in the workshop manual involves taking the catalyst box off the bike first, then removing the exhaust manifolds from the cylinder heads afterwards. That sequence only works if the rear wheel has been removed. The alternative sequence, not mentioned in the manual, is evidently to unbolt the exhaust manifold from the horizontal cylinder head first. That's fine, provided the three nuts (made of putty) can be undone. And provided you have a replacement manifold gasket ready to hand.
Maybe you could have let the air out of the tyre Pete? :biggrin: (I got someone else to fit mine) There must have been a bad bunch of Suonos as a few did have issues. Mine is 3+ years old and still fine if a little louder than when fitted! It definitely improves the safety of biking.
I put the Mivv onto my Mutley on Friday. By far the easiest way is to remove the front manifold bolts, in fact i removed the front pipe completely. Studs and nuts however, are made of the finest Gorgonzola One stud sheared, one nut was ground off one stud came out completely from the head. The salvageable stud was replaced in order to locate the gasket, the other two were replaced with stainless fittings. Removing the front pipe allows a full range of movement for the cat which came away really sweetly. it is now consigned to the spares box. In all honesty, I expected trouble as this part of the motor cops for all the crap and is hidden behind the exhaust shield so stud extractors and heat guns were at the ready along with replacement bolts / nuts. 2 hrs total.
It was a Suono Pete , Lasted about 7 wks...Ghiblis welded so should be OK! To be honest i like the original over & under end cans , Just a decent de-cat option would have done me and a visit to CJS but i cant be arsed now and will probably get something else soon !
