OzVMX Forum
Clubroom => Tech Talk => Topic started by: Graeme M on August 30, 2015, 10:02:44 am
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I took the front wheel off my IT175G the other day to clean out the hub and check brakes shoes and when I reinstalled it I noticed the wheel is not central in the forks. It is off-centre by maybe 10mm or more, sitting very close to the right hand fork leg. I checked it out, took it apart and put it back together, no change. Yet I do not recall ever having noticed that before.
Examining it closely and I can see why it's doing this, it looks like the boss on the brake backing plate is about 10mm too wide and I could fix things by grinding it back by 10mm or so. But that's just silly, surely if the wheel is originally off an IT175 which I believe it is it should fit just fine.
Am I just installing this wheel incorrectly (how? It just bolts on in there) or is it likely this backing plate/hub is wrong for this bike?
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Graeme, if you don't have to stretch the legs apart to get the wheel in, then the backing plate to speedo drive width must be correct. I wouldn't be machining the brake plate if the wheel fits!
Sounds like you might need to re-align the offset of the rim....
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Yep, adjust the rim offset, don't grind anything ;)
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Yes, good point, must be the rim offset. I just measured up the hub and backing plate and it's all exactly correct so it must be the rim. Never even occurred to me!!
Thanks.
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i can take a pic of my backing plate if it helps Graeme
tony
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Thanks Tony, but I have a few spare hubs/backing plates and all are the same. It's the rim offset. Just went and fixed that and not only is the wheel now centred it's now truer!!
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The hubs are pretty much universal for Yammie dirt bikes of that era. Will have 2K7 cast in, in the bottom of the brake drum.
Check the number inside the brake plate. There's a few that are similar, but have slight differences to offsets and the like. For example, TT500 have a very wide fork spacing, so the lug on the forks is very long, and the brake plate is also wider.
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Found that when i was mixing TT & IT bits together,Bigger lump in the centre.
(http://i1260.photobucket.com/albums/ii576/KAB171/fbp_zpsw4s0ca4r.jpg) (http://s1260.photobucket.com/user/KAB171/media/fbp_zpsw4s0ca4r.jpg.html)(http://i1260.photobucket.com/albums/ii576/KAB171/IMG_1661.jpgfbp2_zpsgcvn1shw.jpg) (http://s1260.photobucket.com/user/KAB171/media/IMG_1661.jpgfbp2_zpsgcvn1shw.jpg.html)
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Well it's all good now since I adjusted the offset but I have several old rotten/broken plates/hubs in the shed and I measured them all, including the original off the bike and all match the one on the bike. So it must have been the offset. I had forgotten but I laced up a rim to a good hub that I bought and although I don't recall noting at the time, I mustn't have got it centred. Or it may have been over tightened on one side and has settled over time...
And I finally got to and did some proper testing of the harness and electrics with a decent tester and uncovered a broken wire so now I *think* I may have resolved the ongoing intermittent stopping problems ever since I rebuilt the thing... Only taken me ummm...5 years.
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Thanks Tony, but I have a few spare hubs/backing plates and all are the same. It's the rim offset. Just went and fixed that and not only is the wheel now centred it's now truer!!
And the lesson is.......don't over complicate problems!