ATVNewbie
Newbie
- Joined
- Mar 28, 2009
- Messages
- 1
- Reaction score
- 0
- Points
- 0
Hello,I just bought my 1st ATV...A 1993 Yamaha TimberWolf 250 2x4,paid $25.00 not running,discovered the cam chain was off and stretched,Put a new chain on and runs,but smokes something awful,The guy I bought it from(which he only owned it for a few months)told me it was a 2 stroke, meaning I should pre-mix the gas....I know it has a oil filter and oil pump and I've never seen a 2 stroke with valves and camshaft etc.(I have a repair manual on order).Is this a 4 stroke and the guy is an idiot??Is that why its smoking so bad?It has pre-mix in it now.I just dont want to seize the motor up.Also does anyone know what the valve lash should be set at?Any help would be greatly appreciated. 
Thanks
Thanks
- Joined
- Jun 1, 2004
- Messages
- 7,856
- Reaction score
- 2,048
- Points
- 2,103
- Location
- sudbury on
- Country
- Canada
- Snowmobile
- 2016 apex xtx
2011 apex xtx
2009 phaser rtx/x
1997 et410t/r
1988 vk 540
ok. there are a couple of things you need to check besides the valve lash.
you need to do a compression check to make shure that the valves did not get hit. if it is low, you will need to tear the head off to replace the valves and maybe the piston depending on the damage.
it should not have pre-mix in it at all. that might have been how he was raising the compression so it would run with badly sealing valve or shot piston rings. it will smoke with pre-mix in it untill it is all cleared out.
check that the oil pump is working by losening the banjo bolt for the oil line going to the head. should be on the right side of the head. if it is not, oil pump is full of debris and most likely broke the plastic drive gears in the bottom end (based off of my experiance with yamaha motorcycles).
here is a pic of the valves still in the head that i bent in my xt350 when the timing chain broke in it last fall.
bottom end damage from broken chain
is it smoking like this? this one is smoking from assembly oil and glazed rings. it started clearing up later. it came to the house in 3 milk crates. looks not too bad now.
you need to do a compression check to make shure that the valves did not get hit. if it is low, you will need to tear the head off to replace the valves and maybe the piston depending on the damage.
it should not have pre-mix in it at all. that might have been how he was raising the compression so it would run with badly sealing valve or shot piston rings. it will smoke with pre-mix in it untill it is all cleared out.
check that the oil pump is working by losening the banjo bolt for the oil line going to the head. should be on the right side of the head. if it is not, oil pump is full of debris and most likely broke the plastic drive gears in the bottom end (based off of my experiance with yamaha motorcycles).
here is a pic of the valves still in the head that i bent in my xt350 when the timing chain broke in it last fall.
bottom end damage from broken chain
is it smoking like this? this one is smoking from assembly oil and glazed rings. it started clearing up later. it came to the house in 3 milk crates. looks not too bad now.
