Jump to content
Sign in to follow this  

05 yz 125 jetting and Vermont.

Recommended Posts

I have a 05 and I can't seem to figure out why it smokes so much and drips spooge I have the timing dialed in and new plug and fresh top end I run 40to1 but still drips and smokes I live in Vermont and am not quite sure what my elevation or temps are but it's getting cold here any advice on this thanks guys

Share this post


Link to post
Share on other sites

crank seal or even the crank bearing could be the reason.

it's not like oily smoke it's defiantly premix my premix defiantly has a distinct smell but good thought I thought this too

Share this post


Link to post
Share on other sites

Premix ratio has little to do with spooge, riding style has a big influence in spooge production, spooge being unburnt premix oil.

When putting in your new piston did you have a look @ the piston clearance?

clearance from the head right the head has been milled not sure how much was done before I got the bike

Share this post


Link to post
Share on other sites

Problem #1 , your engine has been modded, and no concrete information is known. Problem #2 is a "new top end" but you have no idea if you have adequate compression. So right now your just taking guesses at what the core issue is. Your going to need to do some research and do some testing. First as always get a compression gage and tell us what the PSI is, you need about 150+ PSI to indicate a healthy top end. If you know the head has been modified, I suggest throwing it on the shelf and finding a stock head. This way you simply run pump premium fuel and have no worries about excessive modded squish and having the need to run race fuel. Lastly open up the carb and document the current jetting.

Share this post


Link to post
Share on other sites

Problem #1 , your engine has been modded, and no concrete information is known. Problem #2 is a "new top end" but you have no idea if you have adequate compression. So right now your just taking guesses at what the core issue is. Your going to need to do some research and do some testing. First as always get a compression gage and tell us what the PSI is, you need about 150+ PSI to indicate a healthy top end. If you know the head has been modified, I suggest throwing it on the shelf and finding a stock head. This way you simply run pump premium fuel and have no worries about excessive modded squish and having the need to run race fuel. Lastly open up the carb and document the current jetting.

thanks man I will check compression I know it's not the best fix but the local shop gave me a thicker head gasket to try to gain alitt more clearance I will check comp and post results

Share this post


Link to post
Share on other sites

thanks man I will check compression I know it's not the best fix but the local shop gave me a thicker head gasket to try to gain alitt more clearance I will check comp and post results

Problem #3 there should not be a "head gasket" late model YZ's use dual o-rings to seal the head. It's possible you have an Athena aftermarket cylinder and/or a big bore kit. More research on your part. If you have the previous owners contact # I definately advise you get the facts about what was done to your engine.

Share this post


Link to post
Share on other sites

Problem #3 there should not be a "head gasket" late model YZ's use dual o-rings to seal the head. It's possible you have an Athena aftermarket cylinder and/or a big bore kit. More research on your part. If you have the previous owners contact # I definately advise you get the facts about what was done to your engine.

the dual o rings are there still there's a thin metal gasket over them it's stock cylinder head is just milled and it's ported and polished

Share this post


Link to post
Share on other sites

the dual o rings are there still there's a thin metal gasket over them it's stock cylinder head is just milled and it's ported and polished

This is the dumbest "band-aid" that I have heard to date. Sometimes its a challenge to seal o rings on a flat OEM aluminum surface, let alone trying to seal o rings on top of a gasket. That being said, now I strongly suggest you throw that head in the trash and go stock OEM, but it's your bike and your choice. If you absolutely need to lower compression in this situation you can add an extra base gasket.

Edited by Polar_Bus

Share this post


Link to post
Share on other sites

This is the dumbest "band-aid" that I have heard to date. Sometimes its a challenge to seal o rings on a flat OEM aluminum surface, let alone trying to seal o rings on top of a gasket. That being said, now I strongly suggest you throw that head in the trash and go stock OEM, but it's your bike and your choice. If you absolutely need to lower compression in this situation you can add an extra base gasket.

this set up works fine I have been running it for a month now and it went thru a leake down test and 4 compression tests I have maintained 170 psi from the day I put the new piston in

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  

×