Jump to content
Sign in to follow this  

Yamaha YZ 250 1998 Rebuild

Recommended Posts

This will be my first rebuild and hopefully everything goes to plan. Brought the bike last year May its my first mx bike :bonk: still completely standard. From the beginning the bike will foul 2 plugs every hour. Fitted a new wossner piston and still did the same found out it was my crank seals. So I figured if im going to split the case I can just aswell do a complete rebuild of the bike. My shopping list so far is: Powder coat the frame, chain and sprokets, new footpegs, spraying the motor, tyers, bearing and seals etc. Here is a few pics of the bike

When I brought the bike

IMAG0396.jpg

IMAG0393.jpg

My piston with only 2 hours on it :smirk: running too rich ? Current jetting Main 170 pilot 48 needle clip 2nd Running 1:40 air screw 2 1/2 turns out and my altitude is at sea level .

SAM_0068.jpg

My reed valve with no stoppers is this normal ?

SAM_0075.jpg

Worn power valve stopper

SAM_0071.jpg

Think my power valve is well matched with my barrel??

SAM_0063.jpg

Head carbon at exhaust port side

SAM_0065.jpg

Where my power valve started touching my piston

SAM_0066.jpg

Share this post


Link to post
Share on other sites

Current state of my bike

SAM_0073.jpg

SAM_0062.jpg

SAM_0061.jpg

Will hopefully get the project done by the end of march.

Share this post


Link to post
Share on other sites

Great photos. I'm glad you posted the pv rubbing the piston pic. YThis will be good to show others who wonder what it looks like.

Share this post


Link to post
Share on other sites

Great photos. I'm glad you posted the pv rubbing the piston pic. YThis will be good to show others who wonder what it looks like.

RCannon

What do you think I should do? tap a screw in the powervalve stopper or use steel putty on the worn part? How much do I need to file my power valve?

Share this post


Link to post
Share on other sites

Nice looking bike! Good luck on your project, make sure to give us lots of picture!

Share this post


Link to post
Share on other sites

Small update on the project. Progress is slow at the moument between my work and studies. New parts arrived today

FMF powercore2 and main bearings

Bellville-20120222-00014.jpg

Is there a reason why the clutch side main bearing looks like this ?

Bellville-20120222-00011.jpg

Crack in my frame :bonk: will get it welded up this weekend

Bellville-20120222-00009.jpg

Is my frame bent?

Bellville-20120222-00008.jpg

Bent subframe will sort it out this weekend

Bellville-20120222-00010.jpg

My shopping list just gets longer and longer by the day lol guess thats the way these projects go

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...