A forum for owners of Yamaha TTR250 trail and enduro bikes!

Vlad · Newbie

Strange clatter from gearbox on 4,5 gears

TTRHead · Senior Member

Have you checked all the basics? Heatshield, engines mounts, exhaust mounts?

Could be the clutch I guess

Vlad · Newbie

I've put the bike on a stand and tried to accelerate on all gears listening to the engine with a stethoscope. Same sound was from the gearbox. What do you think might be wrong with the clutch? I think if the problem was with clutch the noise would at any gears.

TTRfan · Super Guru

Hi Vlad and welcome to the forum!

You are very brave running the TTR on a stand in the high gears doh

The gears on a TTR are very simple and I have not heard of them getting damaged before. 6th gear is known to wear after long road mileages but that isn't the problem with your gearbox.

I am not sure whether 5th and 6th gear are beside themselves in the cluster but, if so, I can only think that some damage may have occurred in that area.

Unfortunately your TTR would require a complete engine strip to split the cases to examine the gears.

Did any swarf come out when you drained the oil or was there any metal shards in the filter?

Best regards

Brian

PS What part of the world are you from? There isn't anything in your profile to give a clue cry

Gear cluster.jpg

TTRHead · Senior Member

Isn't a small amount of metal dwarf normal? Used to get it all the time on my KTM had it a few times on TTRs

I mentioned clutch as I have had a noise before in the gearbox area I changed the clutch and it stopped it but that's just what has happened in my case

TTRfan · Super Guru

Perhaps swarf is the wrong word because if a tooth has chipped there is more likely to be metal shards. A small amount of swarf is always present on an oil change but I am asking Vlad if he has seen more than the usual in his oil drop since the noise started.

Vlad · Newbie

Hi everyone,

Here is my report of what have been done.

The engine has been stripped apart.

Shift forks and shift cam have been inspected.

Shift forks seem to be worn, but i dont know whether it is critical wear or not. Does anyone have any ideas?

The shift cam doesnt have any obvious wear, however, the spocket does have. However, i barely can feel it with my finger, so i dont think it might affect negatively the operation of the gearbox.