4 into 2 system?

[SteveW]

This is my one, no manufacturers marks on it:

[Orcade-Ian]

Thanks for finding and posting the pictures Steve but I don't think that style would suit me.  If I could be sure that the basic head casting and therefore port positions and angles were the same on 500 and 550 plus the distance to mountings the same, then I might go for the Marving system.

Ian

[Bryanj]

500 and 550 head are identical parts mate, footrestpositions might alter but bracketry is the easy bit

[Orcade-Ian]

Thanks for that Bryan, it's very reassuring if the heads are the same.  Assuming they got the extra capacity on the bores on the 550 - I seem to remember you telling Ted that the cranks were the same. Then that means the deck height is the same so should only need the silencer hanger area possibly needing a couple of extra brackets - there's obviously one needed anyway on the left.  Looking at a pic of the 500, are the rear footrest frame hoops the same on 500 and 550, they look very similar to me?

Ian

[Oddjob]

Not the same Ian, the 500 has solid frame lugs and the 550f has tubular frame lugs. It’s possible the 550 has them slightly lower than the 500 but there’s not a lot in it. Oddly the 550k3 having the four exhausts you’d imagine the level would be the same, it may be the brake pedal is the problem with it not fitting.

[Orcade-Ian]

Morning Ken,
Yes, I've just looked again at a better 500 pic and the rear footrest hangers are like my 350/4 (made of 2 clam-shell pieces on mine). Side stand is much farther back on F bikes - that could be another stumbling block as well as the brake pedal.  Wonder if anyone has put this Marving 4 into 2 on an F series?  Might post on the .net site to see.

Ian

[Oddjob]

Thought they only mentioned not fitting to the K3 not the F series Ian?

The F series had a rear brake pedal that sat much further out to clear the 4 into 1 and also the bigger depth clutch cover, the 550K3 has a really odd looking rear brake pedal which could hit the new system.

[Oddjob]

You could consider this Ian,

https://www.ebay.co.uk/itm/282034589307?hash=item41aa924e7b:g:AA0AAOSw-0xYPrsv

Find a set of Cb500 headers and transfer them onto those silencers. Should be a few headers lying around, it's the silencers that rot, the headers are usually fine, plus you don't know if the new headers are double skinned or not. Something to consider as if they aren't they'll blue quite easily.

[Orcade-Ian]

Thanks Ken,
They do look great don't they?  Were 500 headers separate or need to be chopped off rotten  silencers?  Good shout re the double skinning, I know some like the blueing but not me!  I didn't want to modify this bike too much but having a silencer on each side of any multi is always pleasing to my eye (all four of 'em!)

Ian

[Oddjob]

You'd need to chop off the headers from the rotten silencers, if I was doing it I'd grind the old silencer off as you retain more of the header pipe, rather than just cutting them at the join.

[triplE675]

My 2nd 500 K0 had a 4 into 2 system on it both silencers have rotted out but the down pipes are good Will post some pictures tomorrow if they could be of use.?

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[Orcade-Ian]

Thanks for that possibility,
I might be on to an original silencer but would be happy to see these headers as I am still fancying the 4 into 2 set up sometime, so all options are there then.

Ian

[deltarider]

How about the backpulses to help the breathing of the engine? I always heard 4-2 is the lesser of the three options: 4-1, 4-4 and 4-2, performance wise. Is there any substantiation for this?

[triplE675]

Photo's of 4-2 system downpipe appear to be removable

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[Orcade-Ian]

That's a good point Deltarider which I think from memory has been tried and tested with believable results - might have been an I Mech E paper some years back. However, I don't think I will be entering any TTs or one of those 'how far can you go on a gallon of fuel' competitions.  Wonder if they still do those?

I'll study those pics on a proper screen later and get back to you.  Thanks for those,
Ian