Featured Tiger 90 Rebuild

Discussion in 'Vintage Classics' started by Sir Clip, Feb 6, 2022.

  1. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    Barrel now painted with a high temperature engine paint. the paint says it is all right up to 600 degrees C, but i can’t think that the barrels would get hotter than 250 degrees.
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  2. Chris Little

    Chris Little What weather?

    Jan 11, 2022
    15
    3
    UK
    Are all the fins intact?
     
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  3. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    All the fins on the iron barrel are intact. One is missing from the alloy head.
     
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  4. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    Fitted new guides for cam followers.
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  5. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    Barrel, pistons etc fitted all right. A good afternoon in the workshop.
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  6. The Hon. Clip

    The Hon. Clip New Member

    Jun 20, 2022
    6
    3
    California
     
  7. The Hon. Clip

    The Hon. Clip New Member

    Jun 20, 2022
    6
    3
    California
    I used to have a torque wrench, exactly like the one in the picture. The torque wrench with the giant needle pointing to the setting. I've lost track of it though, and am unsure where it can be...
     
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  8. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    I’m sure it’s gone to a good home, where it torques all day long. :)
     
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  9. The Hon. Clip

    The Hon. Clip New Member

    Jun 20, 2022
    6
    3
    California
    But torque is cheap, if the story is good.
     
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  10. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    The engine is in the frame, but the bike is off the bench as my daily ride has just blown a head gasket. In this pic the head has been placed on the barrel just to keep dust out. Someone has wandered in to inspect the bike. :)
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  11. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
    1,154
    243
    appalachia usa
    #251 speedrattle, Jun 24, 2022
    Last edited: Jun 25, 2022
    just a note on that point set.

    the original 4CA unit you have was plagued with awkwardness. crowded, as you have seen, awkward to time because you have to fudge the points gap, and prone to bounce because of the cam.

    the bounce was an issue, because it caused stray sparks which resulted in preignition and detonation, and killed a lot of engines, as i understand it.

    a slightly later 6CA points plate will drop right in, will allow you to put the condendors somewhere cooler, will let you time each cylinder individually,
     
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  12. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
    1,154
    243
    appalachia usa
    you appear to know exacgly what youbare doing. still, just a note on that point set.

    the original 4CA unit you have was plagued with awkwardness. crowded, as you have seen, awkward to time because you have to fudge the points gap, and prone to bounce because of the cam.

    the bounce was an issue, because it caused stray sparks which caused preignition and detonation, and killed a lot of engines, as i understand it.

    a slightly later 6CA points plate and AAU will drop right in, will allow you to put the condensors somewhere cooler, will let you time each cylinder individually, and will give you as good a points ignition as you can get.

    swap meets are good sources for points plates and matching AAU . look fir one that isnt worn out . many were replaced with EI specifically because they were crap, but there are some good used and NOS still out thrre
     
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  13. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    Thank you @speedrattle, that is very useful info. I will add that upgrade on the to do list.
     
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  14. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
    1,154
    243
    appalachia usa
    maybe i should post all that again to make my lack of tech ability even more obvious
     
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  15. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    The good news is that my daily ride is now repaired, so work can restart on the T90. Just for fun, here is a pic of the blown head gasket, no clues.
    D738F298-404E-449B-B6D9-FC7E52BEFD92.jpeg
     
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  16. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    Pulled the ignition coils out of the (shrinking) box of bits. The resistances on the primary coil (two outer connections) and the secondary (centre HT connection and an outer one) are similar to a working 12v coil. That’s close enough to start, i will put them on the bike and see how good they are when i get it running. Need to clean them first.
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  17. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    The carb that was on the bike is an Amal mk1 concentric 930/22. Spec as follows:
    1 3/16 bore
    928 2.5 slide
    needle with 3 ring marks / three grooves, clip in groove 1
    150 main jet
    needle jet not removed
    pilot jet 20.

    The carb that SHOULD be on the bike is an Amal Monobloc 376/300
    15/16 bore
    376 / 3 slide
    needle type C / clip in groove 3
    180 main jet
    .106 needle jet
    pilot jet 20.

    i’m surprised it even ran.
     
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  18. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    Despite the carb being the wrong spec, it’s been stripped, ultra-sonic cleaned and reassembled.

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  19. Sir Clip

    Sir Clip Senior Member

    Jan 8, 2022
    853
    143
    Exeter
    Although it doesn’t look much cleaner the galleries and internals have been washed and blown through with high pressure air. 38419B0C-33BA-4490-A9B4-8291A332B244.jpeg
     
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  20. Baza

    Baza Elite Member

    Jul 25, 2020
    3,441
    750
    Amazing Grace
    If it was OE I thought it would pass muster.
     
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