Jump to content

cylinder and cylinder head busted. Big bore?


kristianybr
 Share

Recommended Posts

Hey guys!

I'm having a few problems with my bike and was hoping some of you could help me out with a few answers.

Currently I have a Yamaha YBR 125 with a busted cylinder, piston and cylinder head. Appearently one of the valves from the cylinder head had broken of and beat an actual hole in the piston! This is the second time in a year that i have had an engine breakdowm (I suspect it is because I bought a cheap china cylinder and piston).

Now I'm considering to buy a big bore kit and a carb so I won't have to drive the bike so hard all the time.

I heave heard that the yamaha ttr and the YBR has the excact same engine, so I think I'm going for a BBR 150ccm kit originally made for the TTR.
But my concern is the carb. I have found a "Keihin 26mm" carb that is often sold together with the 150cc kit, but I don't really know if it will fit on the bike, with all the hoses.
Is there anything else I should think of before ordering this whole headache?
Could anyone please help?

Thanks for any help! :)

PS! I hope I'm having the right forum etiquette. I don't really spend alot of time posting in English forums, and in the Norwegian ones we always end up caps locking at each other with disrespect..

Link to comment
Share on other sites

If your going for the BBR 150ccm kit you might need more air flow too..

not sure if you could just re-jet your carb to accommodate the BBR 150 kit...an i think the xt125x/r is the same engine too!

​personally i never go with the big bore kits, the other engine components are made for a 125 not 150....but thats my personal opinion :)

Link to comment
Share on other sites

  • Moderator

Really? Your killing YBR 125's, so fitting a high strung sports (hi maintainance) top end is ghe way to go?

Daft, it will die all the same. Ride within the bikes limits.

  • Like 1
Link to comment
Share on other sites

The way you ride it Kristian, youy"ve killed 2 top ends, and the big bore kit will not be as robust as factory spec, i would buy a bigger bike, as then it will not be flat out most of its life,,,

Link to comment
Share on other sites

  • Moderator

Why would it die again?

If I change the piston, cylinder, carb and top. Maybe a new clutch. What would make it die?

Those motors are bomb proof, the ONLY thing that kills them so long as they contain at least some oil is constant wide open max throttle. That will kill any engine

Link to comment
Share on other sites

Right..

If I could buy a bigger bike, I would, but because of the laws in Norway the max size I can drive is a 125ccm with 15hp tops.

I guess I'll find a stock cylinder and a ttr/xt cylinder head..

New cylinder heads for the YBR is seriously 1200€!

Thanks for the answers! :)

Hopefully I can get the bike up and running before summer kicks in properly :)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...