mad dad
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| posted on 24/4/07 at 07:50 PM |
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help please on strange noise....
Thought i had a problem on third gear as i was getting a strange grating noise when driving both on up and down changes.....taken engine out stripped
gearbox and nothing wrong!!!!!!! any ideas what else this could be???? propshaft or back axle??? noise appeard to come from box but everything ok in
fact hardly any wear at all and clutch in good condition...only a slight wear on the first fixed gear on the input shaft (clutch end).. It has pitted
on the faces of the cogs and slight scoring but im told it is not bad enough to create a problem. There is also a bit of wear on the selector blocks
on the cogs which are situated on the output shaft . these blocks are the blocks which fit into the gears on the output shaft locking them into place
once that gear is selected the wear is more scoring than pitting but again i am told this is less than would have been expected for age of
engine.......really confused now as engine and box ok....any thoughts anyone?? Thanks for any help as would like to get sorted while engine out
cheers Andy
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tks
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| posted on 24/4/07 at 08:08 PM |
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bearings??
check bearings clearance..
Tks
The above comments are always meant to be from the above persons perspective.
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smart51
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| posted on 24/4/07 at 09:06 PM |
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Is it a noise when selecting 3rd or driving in 3rd? Is it only that one gear? Is it only at certain RPM?
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mad dad
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| posted on 24/4/07 at 10:06 PM |
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its when selecting from 2nd to 3rd and when you come back down again....can't say its rpm specific but it seems the gearbox and clutch are
ok.............is there anything else that might respond to a possible 3000 - 4500 rpm (possible rpm range) outside the gearbox??
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shortie
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| posted on 25/4/07 at 06:43 AM |
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Andy,
Does it drive fine apart from the noise??
Rich.
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mad dad
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| posted on 25/4/07 at 08:08 AM |
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yes it runs great its just a worrying sound however the latest thought is that maybe the linkage is catching somewhere when 3rd is selected????
i'm not sure how much travel there is in the rods but if one has got bent it may be coming into contact with the prop or uj??? i'm away
from home for a couple of days so cannot check for any marks etc but do the rods move much from anyones experience????
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smart51
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| posted on 25/4/07 at 09:57 AM |
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Is the selector fork for 3rd OK? My fork on 2nd (on my old engine) was so bent the the teeth on the gear wheel started to grind into the fork.
Are the dogs or the slots on 3rd worn? Perhaps they're not engaging cleanly.
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MikeRJ
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| posted on 25/4/07 at 11:05 AM |
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It's worth carefully checking the baulk rings on the Type 9. They can crack and cause poor gearchanges, and eventualy will jam the box in gear
if the baulk ring breaks up.
[Edited on 25/4/07 by MikeRJ]
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Hellfire
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| posted on 25/4/07 at 11:51 AM |
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quote:
Originally posted by MikeRJ
It's worth carefully checking the baulk rings on the Type 9. They can crack and cause poor gearchanges, and eventualy will jam the box in gear
if the baulk ring breaks up.
[Edited on 25/4/07 by MikeRJ]
Good advice Mike except this MK has a Fireblade engine and therefore box. 
Phil
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mad dad
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| posted on 26/4/07 at 05:10 PM |
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Thanks everyone for comments still looking but will probably put engine back at weekend as can't seem to see anything wrong!!!!! still open to
ideas though..selector forks fine, no significant wear on the blocks on the backs of the cogs so its mystery.......cheers
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Catpuss
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| posted on 27/4/07 at 07:40 PM |
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Ususallt grading on a bike gear box is down to one or more of:
loose linkages
chain making gear selection sloppy
slight bend or wear in selector forks
worn gears
possibly worn dogs (the teeth on the cogs).
Bike gear boxes are more sensitive than car ones. Normally its the 2nd gear that goes though as this takes the hardest hammering.
I would say check the forks and dogs again. Espesh the forks for any slight bend.
Of course you will get resonance at certain RPMs so what sounds fine at 3K rpm could sound like a bag of spanners at 4K then fine at 5K.
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