How to diagnose carburetor vacuum leaks on your motorcycle


  1. 0
    Posted 01/11/2015 at 7:23 | Permalink

    I have a 2000 Yamaha huge bear 400 where are all of the locations to check
    for vacuum leaks?it runs at a high rpm with choke on ,when I take choke off
    and try to give it throttle ,it back fires then dies.

  2. 0
    Posted 01/11/2015 at 7:49 | Permalink

    I got a 1982 450 honda nighthawk has same problem idles at 3 grand constant
    but every now and then it will jump back down to about 1 where it should be
    i’m guessing the leak isn’t huge because of it jumping back down every now
    and then, but like you I wanted to know how you fixed it I don’t want to
    buy new boots either maybe just tape them up excellent ? would that work ? I
    also don’t have baffles in my exhaust well really there is no exhaust its
    just the header pipes on it right now if I place the pipes back on will the
    idle go down ? 

  3. 0
    Posted 01/11/2015 at 8:09 | Permalink

    85 honda interceptor 700 have this problem with my bike got it tartan out
    vaccum leak and 1 of the cards was leaking gas. ordered new boots and a
    carb rebuild kit. i have the benefit manual and original tool kit can i fix
    these problems myself or should have a professional do it?

  4. 0
    Posted 01/11/2015 at 8:14 | Permalink

    Brother I could use some help,
    Ive been a huge fan of your preside over and what your about. I just jetted my
    carb, runs fantastic at idle and slow speeds but nearly 40 mph 3rd gear and
    higher it whats to back fire and loose power bogges out. Then runs fine
    back out slow speeds.
    Please any suggestions would help

  5. 0
    Posted 01/11/2015 at 8:40 | Permalink

    Hello!, I have a question, I have a kawasaki zzr 250 , year 1992 , and when
    is in idle, the motorcicle stops, if you regulate the idlle less than 2500
    rpm, the engine come slower slower , and then stops, what can happen?

  6. 0
    Posted 01/11/2015 at 9:39 | Permalink

    Thanks for the video! It was very helpful!

    When I open the throttle on my bike, it kills the engine. Is this possibly
    due to an air leak? I used your method of testing and it seems I have a
    leak right after my air box.

    Thanks for any help!

  7. 0
    Posted 01/11/2015 at 10:08 | Permalink

    Nice vid. As always.
    I have a explosion ring visible nearly the boot at the carb facing
    side(forward) on the boot to head.(rear) Bright boom sounds like the
    “cough” when a slide spring is caught or bone idle from age. Only it’s on the
    rear boot. Air leak igniting fuel too soon? or what says ye friend? Much
    appreciation for your vigilant and thorough responses to everybody.

  8. 0
    Posted 01/11/2015 at 11:00 | Permalink

    i got a 300 bayou 4×4 and it starts fine and throttles fine but when i come
    to a stop it quits and the idle is not too low any thoughts what it is

  9. 0
    Posted 01/11/2015 at 11:18 | Permalink

    hi, i have a 86 honda 250sx that start and ides fine but i notice tons of
    gas coming out of the hose that extends from the float bowl. i tartan the
    float and it seems fine. any thoughts?? thanks!

  10. 0
    Posted 01/11/2015 at 12:00 | Permalink

    Howdy just bought a king quad 4wd…Will not start.. Some 1 by-passd the
    fuel pump..Any way it has spark..Did the finger test for compression it has
    substantial compression..Tryn to start with early fluid it wants to
    spark a small but wont fire and appears to be spitting mist back out of
    carb…slightly I’m thinking intake valve adj….You reckon im barking up
    the right tree Danny D

  11. 0
    Posted 01/11/2015 at 12:46 | Permalink

    I have just bought the KZ440 LTD. one of the carbs was leaking naughtily @
    the bowel gasket. So i pulled the carbs apart to check things out. and
    looks like they both need gaskets, 1 needs a new needle. But i noticed the
    diaphram on the top end of the carb; 1 has a hole in it. I’m wondering if
    i need to replace it straight away? Does this make a vacuum leak? What
    will this affect exactly? When i tested the bike it was running ok even w/
    the fuel leak. but i will have to replace the gaskets for sure cause it
    was leaking profusely. Fuel petcock also leaks 8-(

    I just don’t want to throw a ton of money into new parts all at once. I’d
    rather do the vital stuff 1st.
    Fantastic video btw. was super useful.


  12. 0
    Posted 01/11/2015 at 12:53 | Permalink

    Any one have a diagram for fuel lines to carb from petcock. and vac lines
    for a suzuki gs 500f 2007?

  13. 0
    Posted 01/11/2015 at 13:49 | Permalink

    Thank you for your many older bike videos. I own a 1978 Suzuki GS 750,
    which is in really excellent shape. 27 years of loyalty. Vacuum leak video
    helped me so much. I pulled the carbs could but not take out the manifold
    boots due to the bikes age, heat, PB, impact wrench, etc. Sprayed the boots
    with silicone, problem gone

  14. 0
    Posted 01/11/2015 at 14:11 | Permalink

    Have you heard of float bowl flooding?

  15. 0
    Posted 01/11/2015 at 14:48 | Permalink

    I’ve got a ’76 Kz400 with this exact issue. Tested it by spraying some
    throttle body cleaner nearly the boot. So I just ordered two new boots from
    Bike Bandit. Is it pretty simple getting the carbs off to replace these
    boots? I’m a pretty mediocre mechanic lol. 

  16. 0
    Posted 01/11/2015 at 15:18 | Permalink

    Fuck spending thousands in mechanic school when you can watch videos like
    these posted by fellow youtubers spreading knowledge for free

  17. 0
    Posted 01/11/2015 at 16:12 | Permalink

    you, sir, are a genius.

  18. 0
    Posted 01/11/2015 at 16:40 | Permalink

    thanks for teaching me a new method. Do the boots heat up and get softer
    and more air sealed?

  19. 0
    Posted 01/11/2015 at 17:12 | Permalink

    So it will increase in idle only if you have a intake leak? I sprayed all
    nearly intake seals and carb seals and in one spot the idle really
    dropped back down like it was supposed to be? 

  20. 0
    Posted 01/11/2015 at 17:20 | Permalink

    Hey so the same thing pretty much happens to my 82 kz440. except that it
    revs at 8k rpm with choke on start! :( I know that I should start the bike
    as smallest as I can but I gotta start it up to see if what I did fixed it
    or not. What else do you reckon causes this high amount of rev? sounds like
    a massive amount of air from somewhere but i can figure it out

  21. 0
    Posted 01/11/2015 at 18:06 | Permalink

    fantastic vid. I just restored an 80 Suzuki gs450. Try to start it up and it
    revs immediately to red line RPM and bleeds oil. I reckon I have two
    separate problems, but I’d like to take up the rev issue. I’m a technical
    novice, but I’m early to reckon it’s a vacuum leak. Any advice? Thanks.

  22. 0
    Posted 01/11/2015 at 18:24 | Permalink

    it’s sounds like the spit pop I described previous to and my tank is off the
    mounts so it literally jumps a half inch when this happens. Had me a small
    jumpy after a time or two

  23. 0
    Posted 01/11/2015 at 18:39 | Permalink

    Can someone please help me with my pro atv29a, dont judge me lol. But it
    starts and runs perfectly but leaks gas out of the bottom. i found a
    tube that came out awhile back and place it back in place and its been
    leaking ever since. heres my video about it to give you a surpass thought. the
    video is on my preside over but the link is below


  24. 0
    Posted 01/11/2015 at 18:56 | Permalink

    So it will increase in idle only if you have a intake leak? I sprayed all
    nearly intake seals and carb seals and in one spot the idle really
    dropped back down like it was supposed to be? 

  25. 0
    Posted 01/11/2015 at 19:30 | Permalink

    very very helpful, thank you very much!