1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Help Cam chain question

Discussion in 'Yamaha 250cc In-Line 4's' started by ajb0235, Jan 20, 2021.

  1. ajb0235

    ajb0235 Active Member

    Messages:
    13
    Likes Received:
    3
    Trophy Points:
    173
    Joined:
    Jul 31, 2011
    Location:
    Leeds UK
    image.jpeg image.jpeg I'm checking everything, valve clearance ,valve timing because the bike has been stood for a long time, and I have no history, other than 33000 k from new 1989.
    My concern is the way the cam chain sits on the sprockets. It sits very high on the teeth, with plenty of daylight between the teeth and the chain.My concern is that the wrong chain has been fitted at some time. However it doesn't look as if the engine has been split, and everything checks out apart from 1 inlet valve where the clearance is below the 0.004 lower limitat 0.003".

    Is this cam chain/sprocket clearance normal?
     
  2. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    4,264
    Likes Received:
    2,840
    Trophy Points:
    923
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
  3. Frankster

    Frankster See the World before you leave it Staff Member Premium Member Ride and Events Crew

    Messages:
    2,883
    Likes Received:
    1,489
    Trophy Points:
    823
    Joined:
    Nov 19, 2013
    Gender:
    Male
    Location:
    Melbourne
    My Bike:
    Spada, VT250F & ZX2R
    Not sure what bike that is, but the cam chain on a ZXR will often sit up like that until the cam-chain tensioner is released/activated and you turn the engine over a few times (manually). If it's like that with the tensioner on, then I think you have a potential problem.
     
    • Agree Agree x 1
  4. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

    Messages:
    4,215
    Likes Received:
    2,473
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    MT09SP, GSXR250R GJ73A
    Yeah sitting up on the teeth is not good, it can jump a tooth like that. And yes the tensioner being out can do that. You likely need to pull and reset the tensioner. When it is out, make sure the crank and cams are on their timing marks. You can then try to rotate either cam a little to get the chain sitting right. Just make sure all the slack goes on the inlet side, you might have to pull the inlet cam to achieve this.

    make sure the cam caps are fully seated. I find it helps to set the exhaust cam in position and bolt it down first.
     
  5. jmw76

    jmw76 Well-Known Member Premium Member

    Messages:
    592
    Likes Received:
    276
    Trophy Points:
    348
    Joined:
    Mar 12, 2017
    Gender:
    Male
    Location:
    Melbourne, Australia
    My Bike:
    Honda cbr250rr mc22 road + 1 track, Honda RC 162 tribute bike, Honda Spada Vt250, Honda CBR900RR
    Hi Guys,

    I am late to the party I know, but is that the right chain for the application???? It isn't something silly like a silent chain being used where a roller chain should be used? That would certainly explain it sitting high.

    Peter.
     
  6. Bobbyr

    Bobbyr Member

    Messages:
    16
    Likes Received:
    7
    Trophy Points:
    13
    Joined:
    Jan 7, 2021
    Gender:
    Male
    Location:
    United Kingdom
    My Bike:
    1989 FZR 250 R 3LN 1991 TZR 250 R 3XV
    My FZR 250 is the same, although I don't know if this is normal. Removing the tensioner did not cause the chain to sit lower in mesh with the teeth though. strange one
     
  7. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

    Messages:
    4,215
    Likes Received:
    2,473
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    MT09SP, GSXR250R GJ73A
    FZR cam chains are the morse type and not roller type. ZXR's use a (tiny) roller chain.
     
  8. 2valve

    2valve Well-Known Member

    Messages:
    584
    Likes Received:
    212
    Trophy Points:
    323
    Joined:
    Oct 12, 2016
    Gender:
    Male
    Location:
    Glen Innes Australia
    My Bike:
    1985 Yamaha SRX 250
    I'm far from being a expert , but it's like the chain has stretched. I had the same problem with one of my old race pushbikes back in the day's. A new chain was fitted , and problem was resolved.

    It does look weird though sitting so high. To me it should be well seated into the sprocket , i'f my main drive chain was sitting that high on the sprocket , i wouldn't ride the bike.
     
  9. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

    Messages:
    4,215
    Likes Received:
    2,473
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    MT09SP, GSXR250R GJ73A
    Can we have a wider angle shot of both cams, the chain, and pictures of the timing marks please? With good lighting?

    If in doubt, remove tensioner, cams & reset the timing. Fit and bolt exhaust cam first and inlet second. All chain slack to go on inlet/tensioner side.

    If fitting a new chain (open ended with joining link) measure the whole length of the new chain, and compare to the old one when removed, along with flex in the plates when held sideways. Might surprise you how much they stretch.
     
  10. Bobbyr

    Bobbyr Member

    Messages:
    16
    Likes Received:
    7
    Trophy Points:
    13
    Joined:
    Jan 7, 2021
    Gender:
    Male
    Location:
    United Kingdom
    My Bike:
    1989 FZR 250 R 3LN 1991 TZR 250 R 3XV
    exactly, when I noticed mine was like this the first thing I though was that someone has installed an incorrect chain for the cam sprockets. I've never seen anything like this before on any motorcycle or car cam chain.
     
  11. ajb0235

    ajb0235 Active Member

    Messages:
    13
    Likes Received:
    3
    Trophy Points:
    173
    Joined:
    Jul 31, 2011
    Location:
    Leeds UK
    Have a look at pinned post"how to replace your FZR250 cam chain without splitting cases" by linkin, on this forum. Pictures of the cam chain sitting on the sprockets are very much like mine. If there is anyone out there who has their motor out at the moment have a look at the cam chain. I'm coming to the conclusion that they are all like this. Mine hasn't had a replacement chain.
     
  12. ajb0235

    ajb0235 Active Member

    Messages:
    13
    Likes Received:
    3
    Trophy Points:
    173
    Joined:
    Jul 31, 2011
    Location:
    Leeds UK
    image.jpeg image.jpeg image.jpeg MHere's a few more pics.
    I've removed the inlet cam now to re-shim 3 valves. I require 2 X 175 shims and 1x 170 shim. Has anyone in the UK got these? I would swap for 3x180 shims that I have removed.
    Prices for new shims are crazy here. Has anyone tried lapping the shims down on 400 wet or dry paper to remove a small amount?
     
  13. Gen

    Gen Well-Known Member

    Messages:
    154
    Likes Received:
    123
    Trophy Points:
    248
    Joined:
    Aug 16, 2014
    Gender:
    Male
    Location:
    50 K's from South Australia, in NSW
    My Bike:
    blown CBR250r
  14. Murdo

    Murdo The Good Doctor Staff Member Premium Member Ride and Events Crew Contributing Member

    Messages:
    5,800
    Likes Received:
    4,368
    Trophy Points:
    1,148
    Joined:
    May 4, 2013
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Tamworth, NSW
    My Bike:
    1938 Royal Enfield 250, CF Moto 250 V5, Honda's XL250, CBR250, VT250F2, FT500 plus a few others.
    Lapping the shims is usually the last resort, but if you do make sure you grind down the side with the numbers on them so you do not get confused in the future.
     
  15. ajb0235

    ajb0235 Active Member

    Messages:
    13
    Likes Received:
    3
    Trophy Points:
    173
    Joined:
    Jul 31, 2011
    Location:
    Leeds UK
    Yes, I lapped mine down using 600 wet orderly paper and WD40. I only had 3 shims to do, and only 2 or 3 thou to remove. Success!
     

Share This Page