Thumper Club Forum
Technical => Bike Problems/Questions => Topic started by: Danny Baker on June 19, 2007, 12:09:41 PM
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I have a GB500 with a Goldstar silencer ...main jet 165. slow jet 50..Ramair filter.
goes great. Have since changed the silencer for another Goldstar one but this has
a bit more of a baffle. The bike is running a bit rich so I changed the main jet to 160
but the tickover is too fast....1900. throttle stop screw wound out and the idle screw makes no
difference in or out. Have now changed the idle jet to 48 and still the same.
Any ideas would be appreciated.
Danny
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Aye Danny,
Put the old 'silencer' back on. ;-)
I have a duc which is strangled above 5 by a baffled 'Goldie' from Armours. The old 'gutted' job is the business, with no gagging at the top end. Just keep about 3k maximum in town.
Sounds as though something else maybe amiss, and I'm not an XBR, GB afficienado, but I'm sure they'll be along in a while to interogate you!!! ;-)
Regards, Bill
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The old silencer was rusty so it went to the scrap heap.
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i've got armours silencers on my norton, stainless goldies. the baffling inside had rusted and collapsed making the silencer almost impassible to gasses.
enter the jack handle! butchered around from both ends until i could see right through, now it has nice stainless outers and almost no inners. the bike pulls and runs miles better.
when enquiring for a pipe for the enfield the bloke from armours boasted that their pipes meet current noise limits. woo-hoo! just what i didn't want. with a pipe like that the enfield would be putting out negative horse power!
350bullet.
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Aye, That man from o'er the Pond, 'bikeseamus', wrote a lovely piece on inserting sharpened punch bars into the nether regions of silencers and by steady, incremental insertion, achieving the nirvana of a mellow bellow without outward evidence of intrusion.
Somewhere in the legislation, bikes of a certain age are permitted to emit more decibals than the current levels permitted by the ACU at race meetings. The legislation is apparently not retrospective! Long may we burble on the overun.
Bye, Bill.
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The fast tickover has nothing to do with the silencer or jet: they have no effect at tickover. So you did something to the carb whilst changing jets. Is there maybe an air leak, or is the slide not dropping?
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I don't think i have done anything wrong with the re jetting....there's not much that can go wrong.
But there is another symptom that happened when the old silencer was on and has since got worst.
The bike pulls well but when you are keeping a steady speed the bike feels like it's running out of petrol
IE. lumpy.
could the head be cracked ???? or is this carberation.
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OK I've fixed the tickover problem.......valve clearances were too big.
still got the kangaroo feeling when keeping a steady speed. Although not quite as bad as it was.
still looking for ideas.
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Surging, or "hunting" at a steady throttle opening is very frequently a lean condition. Does the bike pop through the exhaust pipe upon decelleration with the throttle off after full warm up? ( What does your spark plug look like? They never lie.)
If so, you should fatten up the mixture a bit. Raise the needle with a shim under it or lower the needle clip if the needle is adjustable. As previously mentiones, a leak in the intake system somewhere between the carb and head will lean it out as well. I will also say again that I soak all my old carb diaphragms in ATF for 24 hours when I clean them.
ATF restores their flexibility and responsiveness and adds years to their life. Check these things out and soak the diaphragm before you change the jets again, then see what results. From there, you may or may not have to re jet. Changing too many things at once often confuses the results of any one mod. Step by step is the best way, and it keeps you from having too many jokers in the deck at once. Good luck, and keep us posted.
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New update.....I have found the exhaust is blowing on the left port (2 into 1 pipe)
would this cause it.
I have checked the plug and it's black soot
I will take the pipe off Friday and reseal the exhaust ports....until then I thank everyone for
the help so far.
Danny
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Thumper Club newsletter #1 (Summer 99) has a picture of that GB, mais non?
GC