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TXT 50 Boy - intermittent clonking noise coming from the gearbox

Featured Replies

Hi Chaps,

Wonder if anyone out there has any wisdom on this one. My lad has a 2000 TXT Boy 50. It run well but eversince we've had the bike, its made a random clonking sound in the gearbox, as though a free bolt is being kicked around in the box. It happens now and then but the bike (thankfully) seems unaffected by it. I've drained the oil and theres no obvious metal particles. I think the only option is to split the casing and see whats going on before it goes bang. Before I do, anyone go any ideas what it could be and if it should be of concern?

Kind regards,

Wayne.

Hi Chaps,

Wonder if anyone out there has any wisdom on this one. My lad has a 2000 TXT Boy 50. It run well but eversince we've had the bike, its made a random clonking sound in the gearbox, as though a free bolt is being kicked around in the box. It happens now and then but the bike (thankfully) seems unaffected by it. I've drained the oil and theres no obvious metal particles. I think the only option is to split the casing and see whats going on before it goes bang. Before I do, anyone go any ideas what it could be and if it should be of concern?

Kind regards,

Wayne.

Haven't got a clue, Wayne, but I agree you should check it out. The on/off nature of the clunk is disconcerting and asymptomatic noises are the hardest to diagnose.

Jon

  • Author

Haven't got a clue, Wayne, but I agree you should check it out. The on/off nature of the clunk is disconcerting and asymptomatic noises are the hardest to diagnose.

Jon

Thanks for the reply Jon. One idea I had was to install a magnetic drain plug in the hope whatever is washing about will stick to the magnet. The current drain plug has no magnet. I've just ordered a drain plug with magnet from GG. Only problem was, GG didn't know if theres any difference between drain plugs of the full size bikes and the Boy 50. They're sending me a drain plug for the full sized bikes.

I'll give it a go, but I can see a strip down.

Any idea Jon, how easy it is to split a Boy 50 box? Don't suppose you have one of your excellent videos showing strip down steps?

Kind regards,

Wayne.

Thanks for the reply Jon. One idea I had was to install a magnetic drain plug in the hope whatever is washing about will stick to the magnet. The current drain plug has no magnet. I've just ordered a drain plug with magnet from GG. Only problem was, GG didn't know if theres any difference between drain plugs of the full size bikes and the Boy 50. They're sending me a drain plug for the full sized bikes.

I'll give it a go, but I can see a strip down.

Any idea Jon, how easy it is to split a Boy 50 box? Don't suppose you have one of your excellent videos showing strip down steps?

Kind regards,

Wayne.

Wayne,

I checked on: http://www.trialspartsusa.com/tech.html and they have some good written info but no videos (Jim Snell does the excellent how-to videos, he's much more handsome than me...) on how to split the 50. My personal experience with the 50/70 is very limited as they are rare in the my area.

As I remember, the engine takes normal tools to service other than the thin-wall socket for the clutch, which can be fabricated. I'm not aware of any unique problems with disassembling or assembling the 50/70 series engine.

I always have some small, strong magnets stuck to the toolbox lid so I can drag one of them through drained oil if I need to check for unusual transmission particles. As for the magnet drainplug, the magnet sticks out a little so be sure there is clearance inside the case when the plug is tightened.

Jon

  • Author

Wayne,

I checked on: http://www.trialspartsusa.com/tech.html and they have some good written info but no videos (Jim Snell does the excellent how-to videos, he's much more handsome than me...) on how to split the 50. My personal experience with the 50/70 is very limited as they are rare in the my area.

As I remember, the engine takes normal tools to service other than the thin-wall socket for the clutch, which can be fabricated. I'm not aware of any unique problems with disassembling or assembling the 50/70 series engine.

I always have some small, strong magnets stuck to the toolbox lid so I can drag one of them through drained oil if I need to check for unusual transmission particles. As for the magnet drainplug, the magnet sticks out a little so be sure there is clearance inside the case when the plug is tightened.

Jon

Bugger! Got the drain plug of the full size bike...as predicted, it doesn't fit because of the magnet...magnet colides with something in the box. GG have now sent me the correct plug for the bike.

Still not sure what the clonking noise is though...more investigation required.

Cheers,

Wayne.

Before you go pulling it apart, my son's new GG50 also has an intermittent clunking noise which I found to be caused by an intermittent drive chain misalignment on the bottom run of the chain. The intermittent misalignment is due to the chain tensioner slipper causing the lower chain run to move left and right. The clunking happens when the chain starts to ride up the sprocket teeth, then jump back down into the correct position again.

  • Author

Before you go pulling it apart, my son's new GG50 also has an intermittent clunking noise which I found to be caused by an intermittent drive chain misalignment on the bottom run of the chain. The intermittent misalignment is due to the chain tensioner slipper causing the lower chain run to move left and right. The clunking happens when the chain starts to ride up the sprocket teeth, then jump back down into the correct position again.

Thanks for that. Unfortunately, it also happens when stationary :( More investigation required...

Cheers,

Wayne.

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