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gearbox death rattle

1793 Views 4 Replies 4 Participants Last post by  thelastbaron
today I messed up a couple of gear changes and started to noticed a kind of clicking/rattling noise when in neutral when stopping at lights. A few miles later, riding along in 5th at 70, I started to lose a lot of power, almost like my clutch was completely slipping, so I dropped to 4th and it was ok again, checked 5th but it did the same thing. slowed down at lights and as I tried going into 2nd and first, the gears were grinding/rattling when changing and after selected, even neutral was chattering whilst stopped.

came off the road and even neutral with the clutch disengaged was rattling, 1st and 2nd both were rattling like mad, but still worked okay... 3rd and 4th didn't seem to make any noise and were responding pretty much normally. 5th was still dodgy, with very little power. rode home almost completely in 3rd gear, with some coasting in neutral, trying to avoid 1st and 2nd at all costs lest my box should lock up

I guess it's something got to do with either the selector drum, selector fork, the dogs on 1st/2nd, input shaft bearings and generally the clutch.

Obviously I need to strip the engine back down to fix the thing, but wondered if anyone experienced something like this rattle in 1st, 2nd, 5th and even neutral ?

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Try tweaking the clutch adjustment first, heck of a lot easier than messing about with the engine.

I'll give that a go, but the clutch does disengage and engage properly, bites around 1/2-2/3 of the way out on the lever. the arm is sitting around 20 degrees below horizontal, so I think it's probably worn plates.

When you say you messed up a couple of shifts,,did you by any chance over-rev the engine?

The loss of power in 5th gear is a bit worrying. Does the oil light ever come on?

yes, I did rev the engine quite high in 4th before going into 5th, but not past the redline, only to about 8-8.5 and it was accelerating nicely all the way up 80mph, when I changed into 5th initially it was ok, but after going for a mile it started to lose power. yes, worrying indeed. but no the oil light never came on.

A few miles later, riding along in 5th at 70, I started to lose a lot of power, almost like my clutch was completely slipping

you should have been revving at about 6 thou at 70

do you mean it was revving high but going slow/er?

these old bikes all clank a wee bit but

summats obviously wrong, what have you been doing to the bike?

any major work/been fiddling about in the guts recently?

yes, I was doing about 6k, when it started to lose power I was still at 6-7k, but the speed fell off to about 45mph, revving higher didn't do anything really. I think it may have dropped to lower revs a while after that but I was kind of worried as there was no hard shoulder and it was a speed limit road (A4 to bath, just before Keynsham)

Engine was out because I had a small spill and cracked a rocker cover, got a few stones in the engine, but luckily it stalled before any damage was done. full strip down and inspection revealed no damage to the bores/bearings or anything else really. I put everything back painstakingly using all the manuals and many photo's and I'm 99.9% sure I put it together right and torqued up accurately. it's done over 100 miles since the rebuild and mostly it's been running very nicely indeed, the gearbox was even smoother than before.

who knows then... I might replace the input/output shaft bearings with new ones because they were not 100% and inspect all the worn parts and swap those out.

just gutted because my garage is miles away in the country and I'll need to walk/bus back after dropping the bike off. need to invest in a trailer for my car.
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