/ Register

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

Pinned C/Shaft Sprocket for FZR 3LN3-5-6-7 & Zeal

Discussion in 'Yamaha 250cc In-Line 4's' started by maelstrom, Jan 18, 2015.

Page 5 of 9
  1. Joker

    Joker See "about me" for contact details. Contributing Member

    Messages:
    2,737
    Likes Received:
    1,399
    Trophy Points:
    798
    Joined:
    Feb 2, 2014
    Gender:
    Male
    Location:
    Switzerland
    My Bike:
    SV1000SK3
    Interesting....

    By the way, I had a chat to another couple of mechanical engineers at work today about the sprocket to get some further perspective.

    The general consensus was that because the sprocket is not "loose" but a keyed fit on the shaft AND the torque is in the direction of rotation, there should be minimal issues with the 2mm gap. It was also suggested any spacer should be on the outside face of the sprocket otherwise the chain is likely to wear down one side of the sprocket (given the OEM orientation).

    I acknowledge that that's just another couple of opinions given nobody has attempted dynamic calculations, but both agreed if there was ability for the sprocket to "quiver" side to side while torqued it would be a different story.

    I'm not sure if that information is particularly valid to some, or if it helps, but it certainly makes me more comfortable with my initial impressions. Again not to say anyone is wrong or right, just trying to add some kind of engineering perspective to the discussion.

    Side note is I'm getting a mate in Atlanta to call JT sprockets directly for me to see if he can get through to engineering and ask some questions. Be interesting to see if that gets us closer to some answers...
     
    Joker, Jan 29, 2015
    #81
  2. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,108
    Likes Received:
    3,477
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    There is a nut, tab washer and a thread on the shaft for a reason. The purpose of a tab washer is to hold a tightened nut in position, not to hold a loose nut in position. If the latter were the case then there would be no need for a nut; a simple circlip and thrust washer would suffice. The engineers at Yamaha know what they are doing.

    Also torque is in both directions. Under deceleration the inertia of the forward moving motorcycle is pushing against the braking force of the engine via the drive train.

    You could be correct about which side the sprocket should face, shoulder in or shoulder out, but no one has given any solid evidence about this. Alignment needs to be determined from the rear sprocket mounting face. I get the impression from Mr @HiveFleetAbyss that the shoulder goes inwards on his Zeal. It only remains to be seen what the 3LN3 owners conclude but thus far it seems that they also think it is shoulder inwards.
     
    Last edited: Jan 29, 2015
    maelstrom, Jan 29, 2015
    #82
  3. Joker

    Joker See "about me" for contact details. Contributing Member

    Messages:
    2,737
    Likes Received:
    1,399
    Trophy Points:
    798
    Joined:
    Feb 2, 2014
    Gender:
    Male
    Location:
    Switzerland
    My Bike:
    SV1000SK3
    Yes both direction of rotation, backwards and forwards in the rotation plane of the sprocket. It would be negligible in the perpendicular plane, if any at all.

    An important point to note here is that my nut was never tight. I took it off by hand with no tools, I basically bent back the washer and loosened it by hand, it wasn't even a strain to do (ie it literally spun off with a twist of the finger, I hardly tried at all). As far as I know it is the OEM sprocket. So either it was removed and reattached at some stage (highly doubt it) or it was originally installed like that.

    Look it's fine (and I mean no disrespect by saying this) to say "Yamaha know what they are doing" but this could easily be a fallacy without having some concrete engineering information behind it. There are masses of people on the internet going around presuming problems with no (or limited) engineering expertise where one may not exist. I'm not saying there isn't a problem here but I have asked several very experienced mechanical engineers (and a maintenance manager) in manufacturing (and I am one myself) and none of us see any major issue with it. Given we haven't done any theoretical calculations but if none of that bears any weight because "it's not exactly the same as Yamaha originally did it and they must have done it for a reason (that we are not entirely sure about)" then that's a perspective some can choose to take.

    Sorry if that sounds blunt, I'm not intending to be a Pr*#k about it - but I believe we need to think outside the box with this a bit, this whole endeavor is based on the assumption of a problem without evidence saying there is an actual problem. I wouldn't be surprised if I speak to JT and they say their calcs are fine and there isn't a problem. Do we need to keep pressing until Yamaha say that?
     
    Joker, Jan 29, 2015
    #83
  4. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

    Messages:
    10,929
    Likes Received:
    6,720
    Trophy Points:
    1,168
    Joined:
    Jun 14, 2012
    Gender:
    Male
    Occupation:
    Between a Rock and a Hard Place
    Location:
    North by NW NSW Oztralia - Tamworth
    My Bike:
    *Kawasaki ZXR250C *Yamaha FZR250R 3LN1 *Yamaha FZR400 *Triumph Bonneville 750 T140V *Triumph Daytona 675 *Triumph Tiger 800XC
    I did ask the Yammy dealer here for a Zeal sprocket and he quoted $80+ so I didn't jump at buying one for experimental purposes when a normal sprocket is $10-15
    The best test would be to buy one and try it , taking into account positioning etc ..... and I was just looking at being able to remove the rubber to reduce the width if necessary

    I guess if we all agree it could/will work Ill get one and give it a go for the 3LN6 ...... just a ridiculous price for a consumable
     
    GreyImport, Jan 29, 2015
    #84
  5. kiffsta

    kiffsta Senior Member

    Messages:
    9,066
    Likes Received:
    6,872
    Trophy Points:
    1,168
    Joined:
    Aug 7, 2010
    Gender:
    Male
    Location:
    Brisbane
    mmm Vulcan, Live Long and Prosper :thumb_ups:

    \\//,
     
    • Like Like x 2
    kiffsta, Jan 29, 2015
    #85
  6. Phil

    Phil Senior Member Contributing Member

    Messages:
    3,613
    Likes Received:
    1,549
    Trophy Points:
    923
    Joined:
    Aug 8, 2010
    Gender:
    Male
    Occupation:
    M C E
    Location:
    Sunshine Coast Qld
    Home Page:
    My Bike:
    Suzuki GT250X7 Kawasaki ZZR600
    Couldn't agree with you more, that is one expensive sprocket.
     
    Phil, Jan 29, 2015
    #86
  7. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,108
    Likes Received:
    3,477
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    Here is the torque setting for the drive sprocket nut taken from the workshop supplement for the 3LN1. This is available on my web page for the 3LN1 carb kit. All motorcycles with a threaded journal on the output shaft require that the nut be tightened against the sprocket.
    [​IMG]
    スプロケット means sprocket
    ドライブ means drive
    6.0 kg m = 43 ft lb
     
    maelstrom, Jan 29, 2015
    #87
  8. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,108
    Likes Received:
    3,477
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    @GreyImport
    You would have to machine 2.75 mm off that very expensive sprocket going by our existing information.
     
    maelstrom, Jan 29, 2015
    #88
  9. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,108
    Likes Received:
    3,477
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    maelstrom, Jan 29, 2015
    #89
  10. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,108
    Likes Received:
    3,477
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    Volunteers Please for the Next Task:

    One thing that needs to be considered is that Yamaha decided to use Zeal output shafts in all of the later 3LN models to save money (@Murdo suggested this a while back). Being cheaper to make a thicker sprocket than a different shaft. They then use this sprocket with the shoulder facing outwards. We need someone to get a $5 point laser from the junk shop and check the alignment on the 3LN3. You need to run the beam along the face of the rear sprocket to determine where the front sprocket outer face would/should be. Of course the rear axle wheel has to parallel to the swingarm pivot before you try this.
     
    • Like Like x 1
    Last edited: Jan 29, 2015
    maelstrom, Jan 29, 2015
    #90
  11. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,737
    Likes Received:
    2,883
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    FZR250R 3LN6
    My local mechanic has a laser chain guide, proper mechanic's tool.

    Of course, I'd need a bike & the sprockets. Not sure how Grey & Grasshopper sorted his one
     
    Linkin, Jan 29, 2015
    #91
  12. Murdo

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

    Messages:
    6,400
    Likes Received:
    4,788
    Trophy Points:
    1,148
    Joined:
    May 4, 2013
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Tamworth, NSW
    My Bike:
    1937 Royal Enfield 250, CF Moto 250 V5, Honda's XL250, CBR250, FT500 plus a few others.
    A piece of string held tight will work too for sprocket alignment.
    Stu, your sprocket nut was probably tight at the factory, but 20 years later it had worn enough to be loose on the shaft.
    Some Honda's use a splined washer with two 6mm bolts to hold the sprocket to the shaft, and sprocket wear along with chewing the shaft splines is a common problem on high mileage bikes. My Maico has a circlip to hold the sprocket on. This I believe is done to help with chain alignment so there is some 'slop' of the sprocket to correct any misalignment.
    The problem with using the thinner sprocket on the later longer shaft is of needing a spacer to get correct alignment and of the reduced surface area of the spline teeth causing increased wear of the shaft.
    All things considered, the thin sprocket will probably last as long as the chain and is a reasonably priced alternative to expensive OEM spares.
     
    • Like Like x 4
    Murdo, Jan 30, 2015
    #92
  13. TechHeadFred

    TechHeadFred Well-Known Member

    Messages:
    1,180
    Likes Received:
    734
    Trophy Points:
    498
    Joined:
    May 11, 2014
    Gender:
    Male
    Occupation:
    IT Systems Engineer
    Location:
    Canberra, ACT
    Home Page:
    My Bike:
    2007 CBF250F, 2004 KLR650, 1992 FZR400, 2 x CB250RS (1980 and 1982),
    Sounds advice from Murdo there.

    Both models of Honda I own have the splined washer and bolts.

    Not being familiar with 428 chains, I'm interested to see if this applies to the FZR400 as well though. Haven't looked at the chain yet!
     
    TechHeadFred, Jan 30, 2015
    #93
  14. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,108
    Likes Received:
    3,477
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    @Murdo
    "Some Honda's use a splined washer with two 6mm bolts to hold the sprocket to the shaft, and sprocket wear along with chewing the shaft splines is a common problem on high mileage bikes."

    I have found this to be the case also. On the bikes with securely fastened sprockets, provided the nut remained tight, there would be no wear of the shaft. It was part of our service procedure to check the nut and tighten if necessary.
     
    • Like Like x 1
    maelstrom, Jan 30, 2015
    #94
  15. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,737
    Likes Received:
    2,883
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    FZR250R 3LN6
    Perhaps with retracing all this, the 520 conversion is a better idea. The only thing to then worry about is the alignment
     
    • Like Like x 1
    Linkin, Jan 30, 2015
    #95
  16. Joker

    Joker See "about me" for contact details. Contributing Member

    Messages:
    2,737
    Likes Received:
    1,399
    Trophy Points:
    798
    Joined:
    Feb 2, 2014
    Gender:
    Male
    Location:
    Switzerland
    My Bike:
    SV1000SK3
    Yep, that's a fair call. I'm probably blind but can you point me where you found that info? I searched through all the manuals and I couldn't find it, but I can read the Japanese.

    Sprocket driveshaft nut. The last part says lock washer.
     
    Joker, Jan 30, 2015
    #96
  17. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,108
    Likes Received:
    3,477
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    Well my bad, I should have asked you first it took me forever to translate the Japanese
    I kept thinking "Now who is that lucky sod who has a Japanese wife?" :)
    The manual supplement for the 3LN1 is on my web page http://www.litetek.co/Carb_Kit_Yamaha_FZR250_3LN1.html scroll down to the bottom and there are some pdf files. I thought Mr Grey @GreyImport had already snatched a copy for the forum library.
    cheers
     
    • Like Like x 1
    Last edited: Jan 30, 2015
    maelstrom, Jan 30, 2015
    #97
  18. HiveFleetAbyss

    HiveFleetAbyss Active Member

    Messages:
    199
    Likes Received:
    97
    Trophy Points:
    128
    Joined:
    Aug 4, 2014
    Gender:
    Male
    Location:
    Brighton, QLD, Australia
    My Bike:
    91 FZX250 Zeal

    Attached Files:

    HiveFleetAbyss, Jan 30, 2015
    #98
  19. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,108
    Likes Received:
    3,477
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    Is it offset like the original part?
     
    maelstrom, Jan 30, 2015
    #99
  20. HiveFleetAbyss

    HiveFleetAbyss Active Member

    Messages:
    199
    Likes Received:
    97
    Trophy Points:
    128
    Joined:
    Aug 4, 2014
    Gender:
    Male
    Location:
    Brighton, QLD, Australia
    My Bike:
    91 FZX250 Zeal
    No its not. As you can see by above image it has that slight raised bit but back is completely flat so could be interesting times ahead.
     
    HiveFleetAbyss, Jan 30, 2015
    #100
Page 5 of 9

Share This Page