1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

Carb question

Discussion in 'XJ Technical Chat' started by Golfbuddah, Sep 24, 2020.

  1. Golfbuddah

    Golfbuddah New Member

    Messages:
    7
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    New Hampshire
    I have a 82 650 rj that idles at 2000 rpm when hot and takes forever to run smooth when cold. There are no air leaks. My mechanic says carbs are not oem but POS Chinese replicas? Previous owner rebuilt them but says they are oem.
    1. How do I find out?
    2. Does anyone have a set?
    3. Are turbo carbs and non turbo interchangeable?
    Thanks Frank
     
  2. dkavanagh

    dkavanagh Well-Known Member Premium Member

    Messages:
    1,301
    Likes Received:
    570
    Trophy Points:
    113
    Location:
    Rochester, NY
    Do you have pictures you could post? Once you have posted 5 messages, your account will be allowed to upload pictures here. There are a lot of knowledgeable folks here who can tell a lot from some good pictures.
     
  3. bigfitz52

    bigfitz52 Well-Known Member Premium Member

    Messages:
    21,283
    Likes Received:
    415
    Trophy Points:
    83
    Location:
    Rural SE Michigan 60 miles N of Motown
    That would help. But before you start messing with the carburetors, have you checked the valve clearances? How many miles on the bike? I'm not aware of anybody making "knock off" Hitachi carbs, so let's see what you have; and it will tell you a lot about "your mechanic." The symptoms you describe are those of a need for valve adjustment and carburetor synch; and it wouldn't hurt to wet-set the floats especially if your previous owner "rebuilt" the carbs.

    A word to the wise: unless you have absolutely unlimited funds, you're going to need to become your own mechanic right quick. You'll quickly go broke trying to maintain a 38-year old bike by taking it to a mechanic. Valve clearances are a prime example. They are absolutely important; the first item of maintenance upon which all subsequent tuning depends; but the process, though simple, is time consuming. Time =$$$. AND it needs to be repeated every 5000 miles, which can get expensive. If your mechanic tries to tell you that the valve clearances are unimportant, find another mechanic asap or buy a service manual.

    Naturally-aspirated 650 Secas (like yours) used Hitachi carbs; the Seca Turbo used completely different turbo-configured Mikuni carbs. They are not interchangeable.
     
    cgutz, k-moe and Rooster53 like this.
  4. Golfbuddah

    Golfbuddah New Member

    Messages:
    7
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    New Hampshire
    Thanks for the info. I will get some pictures and a service manual, i am capable of doing most work. Just limited on time. Bike has 26k.
     
  5. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

    Messages:
    14,626
    Likes Received:
    5,008
    Trophy Points:
    113
    Location:
    near utica, new york
    Yep, show us a couple pics and we’ll tell ya right away
     
    Toomanybikes likes this.
  6. bigfitz52

    bigfitz52 Well-Known Member Premium Member

    Messages:
    21,283
    Likes Received:
    415
    Trophy Points:
    83
    Location:
    Rural SE Michigan 60 miles N of Motown
    We don't need carb pics to tell you to check your valve clearances first, though. (That was why I asked about the mileage)
     
    hogfiddles likes this.
  7. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,854
    Trophy Points:
    113
    Location:
    Great North Woods
    what part of NH are you from Golfbuddah?
    I in the Great northwoods, above the Great Notches
     
  8. Golfbuddah

    Golfbuddah New Member

    Messages:
    7
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    New Hampshire
    I live in Dover. Sea coast area.
     
  9. cgutz

    cgutz Well-Known Member

    Messages:
    1,203
    Likes Received:
    719
    Trophy Points:
    113
    Location:
    SE South Dakota
    If I can check my valve clearances, and replace with proper size shims, anyone can!!!! Just use Bigfitz' very good guide on this site. The first time I did it, when the bike was 20 years old, took a few hours. Now I can do it in hardly any time at all.

    In fact, using this site, I have learned to do all the work on my bike myself. The local dealer and mechanics don't want to even touch the bike.
     
  10. bigfitz52

    bigfitz52 Well-Known Member Premium Member

    Messages:
    21,283
    Likes Received:
    415
    Trophy Points:
    83
    Location:
    Rural SE Michigan 60 miles N of Motown
    Which is a good thing; it's beyond their pay grade. The valve clearance thing is truly no big deal; once they are in spec and the bike gets a few miles on it, they tend to hold. The every-5,000 mile check becomes often nothing more than a check; with an occasional shim swap needed. New bikes with 18,000 mile service intervals often also have their shims under the buckets, necessitating camshaft removal. I'd rather check 'em more often than have to deal with that.
     
    cgutz and k-moe like this.

Share This Page