Exhausted! Muffler problem

NZeta History Forums Help ! Exhausted! Muffler problem

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August 13, 2016 at 3:37 pm #1380

oldmgs
Member

So, thought I was on the home straight with the Nzeta, but not so.

I have a 502 engine in a 501 frame.

A few weeks ago I picked up a nice shiny new muffler in Prague, and I already had a new 502 front pipe. I thought fitting them would be an hours work,; silly me.

Problem is that the front pipe fouls on the right hand support for the stand – the 501 has the stand that goes across the scooter with a foot on each side, while as far as I can tell all the 502s have a single side stand on the left.

When I got the scooter it had a very bodged up exhaust system that attached on the left – and blocked the kick start. The pipe went round in front of the stand cross member. Obviously I want to have the muffler on the right where it should be.

So what to do? Anyone fitted a 502 engine in a 501 frame?

I thought perhaps I could get a single right hand 501 pipe but the fittings are different and I think the angle of the exhaust port would not be right.

Simplest would be to cut off the right hand stand bracket and fit a side stand on the left – does anyone have a spare side stand? And how does the side stand attach? Can I somehow use the left hand stand support bracket that is already there?

I could try and get a new pipe made up, but tricky without a pattern, and as I said the one I have goes to the left.

Any advice gratefully received.

Douglas

August 14, 2016 at 3:43 pm #1381

Blair
Member

Hi Doug

Oh buggar, that is a bit of a problem.

I have a similar experience, but I have a Jawa 175 barrel (I am pretty sure) on my 502 engine.  The single exhaust port come out pointing to the left a bit… whereas the 502 barrel should have the port pointing directly forward.

All 502 Nzetas have the exhaust mounted on the left, but 502 Cezeta’s were still on the right.

I made a header to fit mine and had to avoid the side stand, kickstarter and gear linkage.. was not the easiest thing but is done.  You may be able to do something similar, I ended up routing the header between the engine and behind the side stand bracket.. which is not as big as the 501 stand bracket.

501’s are twin exhaust and come out on angles right and left of centre… so no a 501 header will not work even if you cut off the barrel fittings of the 502 one and weld on the correct flanges.

The header diameter is smaller on the 501 as well.. cannot remember the sizing but is around 4-6 mm less I think.

Might be easier to make a header than cut and weld a new side stand setup, especially if you are already painted?

If you end up selling your 502 exhaust, I’d buy it off you if you like.

 

August 14, 2016 at 4:27 pm #1382

oldmgs
Member

Thanks, all useful info. Spent some time lying on my back staring at the set up and was struck by an idea – cut the bend out of the header pipe and insert a longer length of flexible stanless exhaust pipe and route it in front of stand cross member as the original was. The pipe is 40mm and I have  been looking at local suppliers but so far closest is 38mm – although there is 40mm available on ebay and elsewhere. I shall visit them tomorrow and discuss. There are also a couple of local custom bike exhaust builders, but would mean trailering the bike there.

Cheered myself up by bolting on the trailer hitch/spare wheel carrier I picked up in Prague. That fitted!

Cheers

Douglas

August 15, 2016 at 12:10 pm #1383

Jim
Keymaster

Isn’t that just typical…as Blair said my 502 has the exhaust on the left hand side and I didn’t know there was a difference in pipe diameter between the 501 and 502 although the 502 silencer does look a lot larger than one of the 501’s.

Good idea with the flexible stainless Douglas.

Looks like you will finish just as I start my 501…

August 15, 2016 at 1:05 pm #1384

oldmgs
Member

I had assumed that 502s had the exhaust on the right like Cezetas so my “bodged” system is just the badly made NZ original I think. No proof but I do suspect my 501 frame was originally fitted with the 502 engine. But who knows.

Anyway good news is that for $40 I have a length of flexible hose and two clamps that fits the pipe nicely. Not going to look pretty and once I have it on the road I may take it to a bike exhaust specialist and get a proper header made up..

Cheers

Douglas

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