Thumper Club Forum
Technical => Bike Problems/Questions => Topic started by: Happy Daze on July 03, 2008, 07:23:01 PM
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I find myself drawn to a Madras 500 and may pick one up over the winter. The only thing putting me off is the power. As I'll hardtail and girder it, i won't need a huge increase, but i was hoping to make about 28-30 hp. I was thinking a bigger carb, probably a mikuni, and free up the filter/exhaust. Would this be enough,or would i be looking at more serious work?
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standard 500 is 22bhp (apparently).
a free flowing exhaust and a fiddle with the standard carb will get at a guess 4 bhp more, the standard pipe kills it.
to give you an idea a 500 with pipe and carb fiddle is almost the same as an xt600, just with the power comming in differently.
you'd be surprised just how enjoyable bugger-all horse power is! i don't enjoy my cbr600 as much as i did my 350 enfield.
30 bhp requires more serious work such as gas flowing and cams. i'd leave the compression alone unless you want to throw some serious dosh at a roller big-end.
i'd build it with the carb and pipe done. if you want more then do the work. they are so easy to work on its untrue. removing the head can be done in about 1/2 hour including removing the tank, carb and pipe.
bullet350
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Frankly it is not worth it. It is clearly not the right bike for you if it needs that level of work to make it "right"
just my 2p
Steffan
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Allegedly the newer low emmisions engine when fitted with the factory "highway kit" makes that sort of power.
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Thanks, 26hp would be better, and i would be bending up a stainless straight through anyway. As that engine is a thing of beauty, I could be well on the way to getting it right. It doesn't seem like much work to me as i would love to get a bike "just right". I'd love a Rudge Ulster or a big JAP twin or single, but looking at the prices, i think the madras bike has got a lot going for it. Especially considering spares and things like metal fatigue. Anyway, building bikes is fun.
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Allegedly the newer low emmisions engine when fitted with the factory "highway kit" makes that sort of power.
Sounds good. I went to the RE site, but couldn't find out what exactly the "highway kit" is. Can you shed any light?
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i think the highway kit is a bigger carb, different silencer and different air filter.
if you're building a chop then i'd stick an amal concentric on it- the mikuni copy carb looks worse than crap.
my bullet ran really well with a goldie silencer (any fairly free pipe will do) a concentric carb with an open bell mouth.
if you're doing serious miles then put an old brit style air filter on it to prelong engine and carb life, otherwise an open bell mouth (looks and sounds the nuts anyway).
i tried just a straight pipe like the 30's rudge sprinters but found it flat as a kipper, some sort of silncer is a must in terms of good running.
bullet350
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Exhaust back pressure required to assist cylinder filling with air/fuel mix.
This rusty red pipe on the top of the pile is what you're after:
(http://www.thumperclub.com/photos/2004/birdinapipe.jpg)
Makes a 'tweet' sound! ::)
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Thanks, 26hp would be better, and i would be bending up a stainless straight through anyway. As that engine is a thing of beauty, I could be well on the way to getting it right. It doesn't seem like much work to me as i would love to get a bike "just right". I'd love a Rudge Ulster or a big JAP twin or single, but looking at the prices, i think the madras bike has got a lot going for it. Especially considering spares and things like metal fatigue. Anyway, building bikes is fun.
MMM bending up a stainless.. do you take on work? ;)
R
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MMM bending up a stainless.. do you take on work? ;)
R
[/quote]Not very often to be honest as i am incredibly lazy. Also I'm living in Ireland at the moment.
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About the silencer. It is in mind to drill sme holes in a copper pipe, block the inside end of it, then braze on a dish washer to the outside end and braze it into the pipe.
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(http://www.thumperclub.com/photos/2004/birdinapipe.jpg)
Is the collective noun for exhausts a nest? Or have I made a grammatical tit of myself again?