motor issue

406atvracer38 · 04-10-2011, 07:07 PM

last year i installed big bore kit ran great.this year starts runs not same power.performed leak down test at 60%.fond leak coming from vent and out inspection hole for timing marks.this is from my rings or cylinder wall right?or is there some crankcase seals that would cause this?please any help still out there.

LEOGM5150 · 04-11-2011, 09:37 PM

my guess would be rings. how many hours are on it? any smoke out the tail pipe? if it is your rings it will smoke. how about you valve clearances? when is the last time you checked them. how many times have they been shimmed? could be loosing compression through valves guides and seals.

hook me up with some more details maybe i can help you out.

406atvracer38 · 04-11-2011, 10:11 PM

Hi leo I think your right it does smoke a little.It has many hard hours.my valves are spot on i check them twice a season.it starts rite away.my issue is I have compression coming out my vent,dainplug, or hole where you check timing marks.I was gonna check compression but forgot my gauge at work but had the leakdown tester and air.the only place air is leaking is where i previosly descibed.also it shows 60% leakage.also i had it dyno tune last weak and only had 37hp and there commit was engine damage.I think Im gonna have to tear it down and inspect.

LEOGM5150 · 04-11-2011, 10:50 PM

i am guessing rings. maybe valve seats or seals. if it has many hard hours even with the best maintenance it is probably time for fresh rings (maybe a piston) and a good valve job. at least valve lapping seats and seals. if there is any cupping of the valves i would replace them also. it sounds like you have a nice build it would be sad to see it go kaboom! piston, rings and a valve job or even a new head is much cheaper than an entire engine build. a good cylinder honing should go along with new rings and or a piston.

i know very little about case gaskets so that may be another issue but if it runs good just losing power and compression and building crank case pressure and smoking. i would start with rings and gaskets and while you have the top end off, inspect or have inspected the valves and head. just my 2 cents.

jmthepred · 04-11-2011, 11:41 PM

yep , tear it down and go through it. piston , rings and bore. fresh valves and seals.

406atvracer38 · 04-11-2011, 11:53 PM

last spring head was gone thru when installed 558bbk.I run alot wide open throttle,dunes,racin ect.hard to believe rings only lasted 1 season,but i have abused it also i quess its happiest at WOT.looks like i have work to do.gonna measure taper on cylinder and check over head again, if cyl. checks out gonna just hone and ring it.thanks for responding Leo

LEOGM5150 · 04-11-2011, 11:59 PM

no problem. it sounds like you know your stuff. i hope it is just a hone and re ring job. please let us know what you find good or bad. it can help a lot of people in the future.

have you ever been out to killpecker sand dunes 10 miles north of rock springs wyoming? they are the largest living sand dunes in north america. 2nd largest living sand dunes in all the world.

406atvracer38 · 04-13-2011, 12:33 AM

I have been a auto tech for 22 years this stuff is not the same! No I have not been to killpecker but funny enough me and my buddy were just discussing this last week.we usually ride st.anthonys.how far from st.anthonys approx?sounds like my kinda place to ride!

LEOGM5150 · 04-13-2011, 01:01 AM

i have not been to saint anthony it is 250 miles to the west of me. the killpecker sand sunes are about 300 miles to the south of me. it is much faster for me to get to the killpecker sand dunes. to get to saint anthony i would either have to drive through yellow stone park at 25 mph or go all the way around.

killpecker is 675 miles from polson. saint anthony is 388 miles from polson. so it would be a lot longer trip. i hear saint anthony dunes are great, but i have never been so i cannot compare. what i can say is i have never seen a place on earth like the killpecker sand dunes, best riding i have ever seen in my life. i have rode in a dozen different states and a bunch in mexico and baha california. i still have never rode anywhere so amazing and so vast. even if it is a once in a lifetime ride i think every one should make it there once.

04-10-2011, 07:07 PM	#1 (permalink)
406atvracer38 Member Join Date: Jan 2008 Location: polson Posts: 54	motor issue last year i installed big bore kit ran great.this year starts runs not same power.performed leak down test at 60%.fond leak coming from vent and out inspection hole for timing marks.this is from my rings or cylinder wall right?or is there some crankcase seals that would cause this?please any help still out there. __________________ 06 TLD,wisco 12.5-1 piston,nicholas cams,nicholas carb mods,twin air intake,procom cdi and rectifier,Aaen pipe,pro armer nerfs,trailtech x-bars and clamp,13/38,pro gel grips,fullflight +2 A-arms,RAD +2 rear hub spacer,TM designs front chain slider for 13t problem,engine Ice,NGK iridium spark plug,holeshot xcr's,radiator scoops,hpd dampner,triple rate springs and revalve from wiigstyleracing,450r carb,honda m/c with streamline lines no t-fitting,

04-11-2011, 09:37 PM	#2 (permalink)
LEOGM5150 Senior Member Join Date: May 2006 Location: Powell Posts: 4,616	my guess would be rings. how many hours are on it? any smoke out the tail pipe? if it is your rings it will smoke. how about you valve clearances? when is the last time you checked them. how many times have they been shimmed? could be loosing compression through valves guides and seals. hook me up with some more details maybe i can help you out. __________________ come on over and check out our new site http://www.polarisproriders.com/ 2007 OUTLAW 525 IRS 2001 400 TWO STROKE SCRAMBLER

04-11-2011, 10:11 PM	#3 (permalink)
406atvracer38 Member Join Date: Jan 2008 Location: polson Posts: 54	Hi leo I think your right it does smoke a little.It has many hard hours.my valves are spot on i check them twice a season.it starts rite away.my issue is I have compression coming out my vent,dainplug, or hole where you check timing marks.I was gonna check compression but forgot my gauge at work but had the leakdown tester and air.the only place air is leaking is where i previosly descibed.also it shows 60% leakage.also i had it dyno tune last weak and only had 37hp and there commit was engine damage.I think Im gonna have to tear it down and inspect. __________________ 06 TLD,wisco 12.5-1 piston,nicholas cams,nicholas carb mods,twin air intake,procom cdi and rectifier,Aaen pipe,pro armer nerfs,trailtech x-bars and clamp,13/38,pro gel grips,fullflight +2 A-arms,RAD +2 rear hub spacer,TM designs front chain slider for 13t problem,engine Ice,NGK iridium spark plug,holeshot xcr's,radiator scoops,hpd dampner,triple rate springs and revalve from wiigstyleracing,450r carb,honda m/c with streamline lines no t-fitting,

04-11-2011, 10:50 PM	#4 (permalink)
LEOGM5150 Senior Member Join Date: May 2006 Location: Powell Posts: 4,616	i am guessing rings. maybe valve seats or seals. if it has many hard hours even with the best maintenance it is probably time for fresh rings (maybe a piston) and a good valve job. at least valve lapping seats and seals. if there is any cupping of the valves i would replace them also. it sounds like you have a nice build it would be sad to see it go kaboom! piston, rings and a valve job or even a new head is much cheaper than an entire engine build. a good cylinder honing should go along with new rings and or a piston. i know very little about case gaskets so that may be another issue but if it runs good just losing power and compression and building crank case pressure and smoking. i would start with rings and gaskets and while you have the top end off, inspect or have inspected the valves and head. just my 2 cents. __________________ come on over and check out our new site http://www.polarisproriders.com/ 2007 OUTLAW 525 IRS 2001 400 TWO STROKE SCRAMBLER

04-11-2011, 11:41 PM	#5 (permalink)
jmthepred Senior Member Join Date: Sep 2004 Location: brokeass mountain Posts: 5,612	yep , tear it down and go through it. piston , rings and bore. fresh valves and seals. __________________ Sign up at bigborepredators.com Visit the bigborepredators

04-11-2011, 11:53 PM	#6 (permalink)
406atvracer38 Member Join Date: Jan 2008 Location: polson Posts: 54	last spring head was gone thru when installed 558bbk.I run alot wide open throttle,dunes,racin ect.hard to believe rings only lasted 1 season,but i have abused it also i quess its happiest at WOT.looks like i have work to do.gonna measure taper on cylinder and check over head again, if cyl. checks out gonna just hone and ring it.thanks for responding Leo __________________ 06 TLD,wisco 12.5-1 piston,nicholas cams,nicholas carb mods,twin air intake,procom cdi and rectifier,Aaen pipe,pro armer nerfs,trailtech x-bars and clamp,13/38,pro gel grips,fullflight +2 A-arms,RAD +2 rear hub spacer,TM designs front chain slider for 13t problem,engine Ice,NGK iridium spark plug,holeshot xcr's,radiator scoops,hpd dampner,triple rate springs and revalve from wiigstyleracing,450r carb,honda m/c with streamline lines no t-fitting,

04-11-2011, 11:59 PM	#7 (permalink)
LEOGM5150 Senior Member Join Date: May 2006 Location: Powell Posts: 4,616	no problem. it sounds like you know your stuff. i hope it is just a hone and re ring job. please let us know what you find good or bad. it can help a lot of people in the future. have you ever been out to killpecker sand dunes 10 miles north of rock springs wyoming? they are the largest living sand dunes in north america. 2nd largest living sand dunes in all the world. __________________ come on over and check out our new site http://www.polarisproriders.com/ 2007 OUTLAW 525 IRS 2001 400 TWO STROKE SCRAMBLER

04-13-2011, 12:33 AM	#8 (permalink)
406atvracer38 Member Join Date: Jan 2008 Location: polson Posts: 54	I have been a auto tech for 22 years this stuff is not the same! No I have not been to killpecker but funny enough me and my buddy were just discussing this last week.we usually ride st.anthonys.how far from st.anthonys approx?sounds like my kinda place to ride! __________________ 06 TLD,wisco 12.5-1 piston,nicholas cams,nicholas carb mods,twin air intake,procom cdi and rectifier,Aaen pipe,pro armer nerfs,trailtech x-bars and clamp,13/38,pro gel grips,fullflight +2 A-arms,RAD +2 rear hub spacer,TM designs front chain slider for 13t problem,engine Ice,NGK iridium spark plug,holeshot xcr's,radiator scoops,hpd dampner,triple rate springs and revalve from wiigstyleracing,450r carb,honda m/c with streamline lines no t-fitting,

04-13-2011, 01:01 AM	#9 (permalink)
LEOGM5150 Senior Member Join Date: May 2006 Location: Powell Posts: 4,616	i have not been to saint anthony it is 250 miles to the west of me. the killpecker sand sunes are about 300 miles to the south of me. it is much faster for me to get to the killpecker sand dunes. to get to saint anthony i would either have to drive through yellow stone park at 25 mph or go all the way around. killpecker is 675 miles from polson. saint anthony is 388 miles from polson. so it would be a lot longer trip. i hear saint anthony dunes are great, but i have never been so i cannot compare. what i can say is i have never seen a place on earth like the killpecker sand dunes, best riding i have ever seen in my life. i have rode in a dozen different states and a bunch in mexico and baha california. i still have never rode anywhere so amazing and so vast. even if it is a once in a lifetime ride i think every one should make it there once. __________________ come on over and check out our new site http://www.polarisproriders.com/ 2007 OUTLAW 525 IRS 2001 400 TWO STROKE SCRAMBLER