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748 Alloy Subframe

Discussion in '748 / 916 / 996 / 998' started by Bullitt, Sep 25, 2017.

  1. Hi all,

    I've bought an alloy subframe, used obviously, the seller assured me that it was straight... however, as with most items - you pays your money, you takes you chances..

    Now, I think it's ok but I have a question for those perhaps more aware than me:

    Do the lower fixing points on the frame sit at different heights meaning that if the frame was sat on a level surface in the correct orientation, the frame would rock? If it turn it on it's back it's level and doesn't rock.

    Cheers!
     
  2. Hi mate. Don't think the lower mounts are offset. Measure the hole centres on the frame itself to check.
    If in doubt, I can measure the centres on mine tomorrow.

    Cheers, ian
     
  3. The caliper I have won't reach centre to centre. But I did measure the distance form the lower to the upper fixing using some string and the length is the same on each side. So, I have no idea now...

    It doesn't look bent or stressed at any point, so I'll have to fit it up against my frame next time I get a chance! Weird..
     
  4. Just checked my monoposta alloy subframe and the main fixings a level and in line. Sounds like your seller has been less than honest. Andy
     
  5. Seems that way Andy. Shame, I asked everything before hand and he assured me it was ok. Plenty chat before taking the cash - zero chat after I asked him about it. Guess it's the world we live in now...

    I'm sure I can have it fixed though, so not all is lost.
     
  6. So I got in touch with the seller and he is being very honest with me, so thats a good thing. He pulled out another frame from a different company (DM) and it seems to be the same - ie when on a flat surface it rocks just the same as the one have. Is this correct?

    I have video's but I can't upload them...
     
  7. I got given a 9*6/748 standard BP subframe a year or 2 back off a kind forum member, that "rocks" the same and I asked him the same question, he said he had never noticed and it had always been fine. To be honest it's still on the shelf, i've not tried to fit it. If i get chance i'll try to put a vid up.
     
  8. So I have re-checked my early 2000 (not braced), 748R, 1.6M mono sub frame in all planes and it does not rock. The 2 upper and 2 lower main fixings holes are in line horizontally and the vertical spacing between the lower and upper fixing holes are equal. Is the sub frame you bought OE or after market ? If aftermarket, could that be the problem ? Sound like you are going to need to flex your muscles :punch:. Andy
     
  9. It's really hard to photo. If I put the subframe on a flat surface and push down on the back right with subframe facing me with tank/seat part towards me, the front left lifts up about 3mm.
    IMAG1780.jpg
     
  10. @Android853sp I don't think it's an aftermarket item. There are some engravings on the frame - MT 34-0 iirc...

    @Cream_Revenge, Thanks for that. Sounds similar to mine however: On a flat surface, with both rearward lugs for the rubber screws flat, the front right (if looking at the frame long ways, front to back) lower fixing point is raised away from the surface, probably by about 3mm.

    This is peculiar.
     
  11. Finally, I got around to looking at this again.

    So, hopefully the pictures explain all...

    When on it's back, completely level and does not rock at all. When on it's front there is a gap of about 4-5mm when it is level (with a spirit level) at the left side of the frame..

    I have to say, there appears to be no damage to the frame.

    So, what's the verdict. Have I been had, or is it ok?

    IMG_1370.JPG IMG_1366.JPG IMG_1367.JPG IMG_1368.JPG IMG_1369.JPG
     
    #11 Bullitt, Oct 5, 2017
    Last edited: Oct 5, 2017
  12. Been used by a bloke with one arse cheek far heavier than the other who only rides round right hand turns.
     
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