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

mariaKaigiwnis · Member

TTR-250 loud tick sound after rebuild

Christos · Veteran Member

Sounds like valves or timing chain stretched or chain tensioner not deploying fully. Does the ticking lessen or disappear when warmed up?

mariaKaigiwnis · Member

I never left on for long enough to check if the noise settles down because whatever it is it sounds not good blankstare . I will try and keep it on for 10 minutes and see. What do you mean the timing chain being stretch? Can a really stretched timing chain cause this kind of sound? Thanks!

Christos · Veteran Member

I had to replace the chain, similar noise but not so loud. The following link will help you, it is from the group's page. Recheck the timing, the tensioner, I hope the correct torque settings were applied during the rebuild. Did you check the cams for wear? Was it within the specs?
ttr250.com/Removing_Cylinder_Head/TTR_head_removal.htm

mossproof · Super Guru

It sounds like a cam chain rattle to me too. Are both the chain sliders in the correct positions and in good condition?

Ttboof · Senior Member

mossproof wrote:
It sounds like a cam chain rattle to me too. Are both the chain sliders in the correct positions and in good condition?

Agree check the chain is tight when you take the top cover off . It's easy to muck up the chain guides

Dan-in-a-Van · Veteran Member

I had a Honda Dream that had a similar sounding "click". It was a bent valve stem. One of the valves would stick open and then click shut as the piston came up. I had a spare head so I swapped it and fixed the problem before I found the valve stem was bent.

mariaKaigiwnis · Member

Hello again. First of all i would like to thank everyone for the suggestions and the interest! I opened up the top end again to check for a last time that everything was correctly in place. Clearences were correct, timing was correct and cam tensioner was doing the job. So i took off the cylinder to check the new piston only to realize that it was broken. I replaced it with original parts and now the motorcycle seem to be working as its supposed to! No sound coming from the engine and compression test showed 175psi! biggrin

mossproof · Super Guru

Glad you found the cause and solved it. Thanks for completing the story.
Which bit was broken? Rings?

mariaKaigiwnis · Member

I think that the rings were ok. What i hadn't noticed before was that the piston had a slight groove on the center. So when the first combustion occurred that small groove was the lowest point of the piston's surface, most of the energy was transferred there, and as a result cracks formed on the piston. I have some assumptions but i am not completely sure what was the cause of the noise. After i replaced it both the noise and the oil burn(which was crazy with the cracked piston biggrin ) went away and now i am happy again! aww aww

TTRfan · Super Guru

Wow - where did you source the new piston so that other owners might be warned please?

mariaKaigiwnis · Member

A mechanic found it for me, he told me that it was a knock off and that it wont last as long as the original but i will be safe for at least 100k km(oops). So i dont know the exact source but given that it costed 50€ it shouldn’t have been high quality. Initially i wanted to replace it with the original part but my country has huge import taxes and the price was sky rocketed. Finally i got my lesson😇. Cheers!