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BS38 alternatives

Discussion in 'The Garage' started by peanut, Apr 7, 2017.

  1. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

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    I've been looking to buy a spare set of late BS38 carbs for my 79special ll for nearly 3 years now and I've only seen 2x sets advertised on UK ebay . They are like hens teeth over here.

    Are there any viable alternatives I cound use from another more contemporary bike late 1990s early 2000 ? i don't mind doing a bit of modding if necessary .
    i am not really interested in going the VM route I'd rather stick with cvs but I'm open to suggestions especially from someone who has actually used them
     
  2. 650Skull

    650Skull Dinosaur Lives Top Contributor

  3. angus67

    angus67 Welder's penetrate deeper!!

    What about ninja carbs? There is a thread around here somewhere.........
     
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  4. timbeck

    timbeck XS650 Junkie XS650.com Supporter

    I just fired up my new project bike today for the first time.. I'm using the Ninja EX500 carbs. It started on the second kick, scared the crap out of me because I never figured it to start on the second kick. I believe the carbs played a large part of the quick start up. They are also nice and light weight.
    tim
     
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  5. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

  6. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

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    yeah they look really nice but the problem is I don't have a spare set of carbs to send him ...that is the problem. I'm looking for a spare set of carbs so that every Spring i have a spare set of clean carbs to swop and the bike is never stood unused due to being without carbs .

    i've been looking at at some of the later 4x pot models and wondering if say the 1996 XJ600 could be made to work or the 2003 XJR1300
    Mikuni 5ea210 h163 etc They are cheap as chips and only 15 years old and parts are plentiful.
     
  7. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

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    mmm good suggestion thanks . I hadn't considered them because they are so small bore . I will look into them but I would rather use something a little more modern as these are still 25+ years old and mostly knackered .
     
  8. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

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    wow are we digging up old past threads now 2M ?
    As I said in my post above I'm not looking at VM carbs only CV ;)

    I dismissed the Amals after some further investigation and chatting with the manufacturers for some 6+ months. After initial promises of developing a plug n play set for XS650 they couldn't be bothered to look into making some inlets and choke linkage
     
    Last edited: Apr 8, 2017
  9. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

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  10. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

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    great link thank you g.
    I'll peruse this afternoon whilst I am babysitting the MIL :rolleyes:

    I had hoped to find a more modern alternative which will be inmuch better condition cheaper to buy and spares much more plentiful . I suspect that the EX500 will turn out to be a similar expense and pita as the BS38
     
  11. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    They are by all accounts a good upgrade, a bazillion were put on years and year of Kawi's. I did a refresh of a set on my nephews ninja, they were easy to do. Nothing wrong with BS34's either.....But the kawi are more advanced.
     
  12. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    p.s. Mr Riggs has a set in use for over a year now, THAT'S say'n something!
     
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  13. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

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    well.......... if Mr Riggs says they are ok they must be lol:laugh2:

    I just did a bit of reading up and it turns out that the UK version of this bike was called GPZ500 and they are fairly common. used carbs are a little cheaper than BS38s and were produced into the early 2000s so it should be possible to get a set in good condition.
    ideally I wish to have 2x identical carb setups so that I can clean and adjust one set and always have a set on the bike .
    There are plenty of early BS34s available but in very poor condition and I would need to buy 2x sets plus parts which would work out very expensive and leave my current BS38s redundant
     
  14. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

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    Are the EX500 carbs really at the same centres as the XS650 ?
    presumably the venturi are a smaller diameter so you'd need some new rubber inlets to suit.
    I have a chance of 2x sets of GPZ500 (EX500) carbs and just need some confirmation about fitting before I hit the ebay button:D
     
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  15. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

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  16. aldo5468

    aldo5468 Redleg XS650.com Supporter

    Yes, they are on same centers - that's one of the reasons these carbs make such a good swap on our 650's. They fit stock Yamaha inlets used with BS34's, but if changing carbs anyway, good opportunity to inspect your old stock inlets and replace if necessary. If you do go this route, make sure you relieve the top bracket enough to give decent clearance from the frame downtube; otherwise you'll get a lot of unwanted vibration transmitted into the carbs.
     
  17. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

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    thanks for the tip about clearance. I'll compare with my BS38s that are coming off and alter the GPZ500 bracket . Luckily I get very little vibration on my bike
     
  18. I have CVK carbs on my 750 big bore they perform really good. Sell those 38 on ebay.
     
  19. Aussie

    Aussie XS650 Enthusiast

    Sell me your 38's ;-)
     
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  20. peanut

    peanut XS650 enthusiast & inveterate tinkerer XS650.com Supporter Top Contributor

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    :D:D you couldn't afford them :D

    Seriously they will stay with this bike and eventually be sold with it when I fall off the perch. its a very original unmolested bike .

    In truth these BS38s are no better than any other carbs . its all about being absolutely meticulously anal when cleaning and setting them up to get them to work properly. I thought that I was a very attentive person when it comes to mechanical stuff but these carbs are a nightmare to get set right and require a new level of Defcon 1 anal attentiveness. :cussing:

    If you look at the minute size of the fuel jet and air emulsion drillings in the Pilot jets and realise that that is pretty much all the air the engine needs to run at idle ....you begin to realise how even the very tiniest of air leaks can cause starting, running and snap throttle problems.
     

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