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acecycleins · 07-06-2010, 08:53 AM

Cuddy or any other 2stroke guys.

My nephew's CR85 has a blow-by issue off the manifold and the expansion chamber. I thought the dealer would hand me the correct parts after ordering them, but I was wrong. They gave me the rubber seals and what looks like a crush washer for a 04 85 Expert.

The original metal joint gasket was cleaned and looks fine and the joint seal was cleaned as well. The questions is: How much seepage should be happening? Before I pulled these things apart you could visibly tell that exhaust smoke was coming from the manifold area. Not huge but absolutely noticable. The parts look fine, but I'm not really a two stroke guy so I was wondering if the $11 worth of raplacement parts will seal the exhaust or if it's rather normal for these little 85's to have this issue.

Are there any other parts other than these two pieces that i should look into replacing (like the manifold itself) or is what I re-ordered going to fix his issue?

Kirk

MOKE1K · 07-06-2010, 12:42 PM

Manifold as in intake or exhaust. How many hours are on the bike that you know of? Is the bike losing power? And finally is it a heavy black sticky stuff that's creeping out? Pics would help although I am sure Cuddy would get straight to the heart of the diag. quicker then I.
Obviously gaskets will leak more when they have been crushed once previously. Check all the mounts to the exhaust and move the head of the pipe to and away from you see how lose it is completely bolted together.

acecycleins · 07-06-2010, 12:56 PM

Quote:

Originally Posted by MOKE1K

Manifold as in intake or exhaust. How many hours are on the bike that you know of? Is the bike losing power? And finally is it a heavy black sticky stuff that's creeping out? Pics would help although I am sure Cuddy would get straight to the heart of the diag. quicker then I.
Obviously gaskets will leak more when they have been crushed once previously. Check all the mounts to the exhaust and move the head of the pipe to and away from you see how lose it is completely bolted together.

Exhaust. No big smoke. Just light in color. No power loss. Just smoke coming off the front of the expansion chamber right at the manifold.

MOKE1K · 07-06-2010, 06:19 PM

Change the gaskets, note how loose is loose for the matting surface's of the exhaust. I am not sure what year I am dealing with but a lot of these pipes are held on with springs initially then require bolts past the main portion of the header.

I'd say your alright without seeing pics. Not also sure how your son rides it but it will load up after the rider putts around for a bit. As you probably know you have to be on the gas for this type of bike to run properly. Replace the gaskets and o rings depending on the last time these peices were replaced, besides it's eleven dollars? Ride it until it really becomes a problem
As long as your servicing it on time properly you should be ok. Good luck.

MOKE1K · 07-06-2010, 06:32 PM

By the way do you keep up regularly with the maintenance schedule? When do they state to replace these items. Tell me you have an owners manual.

acecycleins · 07-06-2010, 06:42 PM

All this is new actually. I've been a street rider for 27yrs. I know enough about 2strokes for fake basics but when I pulled the pipe off it seemed as though there were o rings missing. Not sure, though, bucause this is the first time playing with a tiny motor. The spring certainly was holding it in place and accoding to the manual the torque for the bolts was a scant 7ftlbs. I just want to make sure I have the correct parts before buttoning it up.

pplassm · 07-06-2010, 06:46 PM

In my experience, all racing two-strokes, that is, all bikes having exhausts that are held on with springs, leak to some degree. They may not when brand spanking new, as the pipe end and exhaust spigot are unworn. (Been a long time since I've owned a brand new bike.)

Operational vibrtion takes it's toll on the joint, hence the spring mounting. In fact the engine and pipe mounts and frame flex all probably play a part in flex at that joint.

The only sure way to completely seal the joint is to replace all worn components, including pipe and spigot (probably part of the cylinder on an 85). The isure all pipe and engine mounts are secure and flex-free.

All this may not be worth the price of cleaning with a good degreaser after exery ride.

MOKE1K · 07-06-2010, 07:29 PM

He is correct if it's primarily held on with springs it's going to be lose. It's meant to be that way and will wear in and move more than expected.

An o-ring usually has a visible seat or inlay. Also I have used RTV to overcome a serverly worn matting surfaces. If it's new and has less than 100 hrs, I'd say your fake basics on two strokes is fine and your just worrying about nothing.

acecycleins · 07-07-2010, 07:33 AM

All good then. Just making sure what I'm seeing is normal compared to street bikes. Guess I'm going to have to pony up for a Bultaco to learn some things. Got a friend that is willing to let me have one of his three for about $800. It runs even.

mscuddy · 07-07-2010, 06:34 PM

All racing two-stroke MX bikes leak a little from the exhaust port/headpipe joint. It's like that so the vibration from the motor doesn't manifest itself into cracks and other bad news on the chamber side. I use to double-up the springs on my CR500, seemed to keep the pipe seated better. If you'll notice the whole chamber is rubber mounted, if it were mounted solid the expansion chamber would be toast in a few hours of riding.

07-06-2010, 08:53 AM	#1
acecycleins Founding Member Join Date: Jun 2007 Location: North Georgia Posts: 4,125	My Nephew's CR85R Cuddy or any other 2stroke guys. My nephew's CR85 has a blow-by issue off the manifold and the expansion chamber. I thought the dealer would hand me the correct parts after ordering them, but I was wrong. They gave me the rubber seals and what looks like a crush washer for a 04 85 Expert. The original metal joint gasket was cleaned and looks fine and the joint seal was cleaned as well. The questions is: How much seepage should be happening? Before I pulled these things apart you could visibly tell that exhaust smoke was coming from the manifold area. Not huge but absolutely noticable. The parts look fine, but I'm not really a two stroke guy so I was wondering if the $11 worth of raplacement parts will seal the exhaust or if it's rather normal for these little 85's to have this issue. Are there any other parts other than these two pieces that i should look into replacing (like the manifold itself) or is what I re-ordered going to fix his issue? Kirk __________________ "Slack" - a state of being in which everything flows smoothly.....a frame of mind so at ease that the universe naturally cooperates.

07-06-2010, 12:42 PM	#2
MOKE1K Registered Member Join Date: Jul 2008 Location: Kalapana, Big Island Posts: 3,956	Manifold as in intake or exhaust. How many hours are on the bike that you know of? Is the bike losing power? And finally is it a heavy black sticky stuff that's creeping out? Pics would help although I am sure Cuddy would get straight to the heart of the diag. quicker then I. Obviously gaskets will leak more when they have been crushed once previously. Check all the mounts to the exhaust and move the head of the pipe to and away from you see how lose it is completely bolted together. __________________ "YOU CAN'T BOLT ON SKILL" "The only thing limiting your bike, is you" We survived Bush you'll survive Obama! "the most fundamental fact about the ideas of the political left is that they do not work. therefore we should not be surprised to find the left concentrated in institutions where ideas do not have to work in order to survive." --thomas sowell

07-06-2010, 06:19 PM	#4
MOKE1K Registered Member Join Date: Jul 2008 Location: Kalapana, Big Island Posts: 3,956	Change the gaskets, note how loose is loose for the matting surface's of the exhaust. I am not sure what year I am dealing with but a lot of these pipes are held on with springs initially then require bolts past the main portion of the header. I'd say your alright without seeing pics. Not also sure how your son rides it but it will load up after the rider putts around for a bit. As you probably know you have to be on the gas for this type of bike to run properly. Replace the gaskets and o rings depending on the last time these peices were replaced, besides it's eleven dollars? Ride it until it really becomes a problem As long as your servicing it on time properly you should be ok. Good luck. __________________ "YOU CAN'T BOLT ON SKILL" "The only thing limiting your bike, is you" We survived Bush you'll survive Obama! "the most fundamental fact about the ideas of the political left is that they do not work. therefore we should not be surprised to find the left concentrated in institutions where ideas do not have to work in order to survive." --thomas sowell Last edited by MOKE1K : 07-06-2010 at 06:26 PM.

07-06-2010, 06:32 PM	#5
MOKE1K Registered Member Join Date: Jul 2008 Location: Kalapana, Big Island Posts: 3,956	By the way do you keep up regularly with the maintenance schedule? When do they state to replace these items. Tell me you have an owners manual. __________________ "YOU CAN'T BOLT ON SKILL" "The only thing limiting your bike, is you" We survived Bush you'll survive Obama! "the most fundamental fact about the ideas of the political left is that they do not work. therefore we should not be surprised to find the left concentrated in institutions where ideas do not have to work in order to survive." --thomas sowell

07-06-2010, 06:42 PM	#6
acecycleins Founding Member Join Date: Jun 2007 Location: North Georgia Posts: 4,125	All this is new actually. I've been a street rider for 27yrs. I know enough about 2strokes for fake basics but when I pulled the pipe off it seemed as though there were o rings missing. Not sure, though, bucause this is the first time playing with a tiny motor. The spring certainly was holding it in place and accoding to the manual the torque for the bolts was a scant 7ftlbs. I just want to make sure I have the correct parts before buttoning it up. __________________ "Slack" - a state of being in which everything flows smoothly.....a frame of mind so at ease that the universe naturally cooperates.

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07-06-2010, 06:46 PM	#7
pplassm Founding Member Join Date: Nov 2001 Posts: 3,875	In my experience, all racing two-strokes, that is, all bikes having exhausts that are held on with springs, leak to some degree. They may not when brand spanking new, as the pipe end and exhaust spigot are unworn. (Been a long time since I've owned a brand new bike.) Operational vibrtion takes it's toll on the joint, hence the spring mounting. In fact the engine and pipe mounts and frame flex all probably play a part in flex at that joint. The only sure way to completely seal the joint is to replace all worn components, including pipe and spigot (probably part of the cylinder on an 85). The isure all pipe and engine mounts are secure and flex-free. All this may not be worth the price of cleaning with a good degreaser after exery ride. __________________ Mongo just pawn in game of life.

07-06-2010, 07:29 PM	#8
MOKE1K Registered Member Join Date: Jul 2008 Location: Kalapana, Big Island Posts: 3,956	He is correct if it's primarily held on with springs it's going to be lose. It's meant to be that way and will wear in and move more than expected. An o-ring usually has a visible seat or inlay. Also I have used RTV to overcome a serverly worn matting surfaces. If it's new and has less than 100 hrs, I'd say your fake basics on two strokes is fine and your just worrying about nothing. __________________ "YOU CAN'T BOLT ON SKILL" "The only thing limiting your bike, is you" We survived Bush you'll survive Obama! "the most fundamental fact about the ideas of the political left is that they do not work. therefore we should not be surprised to find the left concentrated in institutions where ideas do not have to work in order to survive." --thomas sowell Last edited by MOKE1K : 07-07-2010 at 02:33 AM.

07-07-2010, 07:33 AM	#9
acecycleins Founding Member Join Date: Jun 2007 Location: North Georgia Posts: 4,125	All good then. Just making sure what I'm seeing is normal compared to street bikes. Guess I'm going to have to pony up for a Bultaco to learn some things. Got a friend that is willing to let me have one of his three for about $800. It runs even. __________________ "Slack" - a state of being in which everything flows smoothly.....a frame of mind so at ease that the universe naturally cooperates.

07-07-2010, 06:34 PM	#10
mscuddy MODERATOR X Join Date: Jun 2007 Location: Next to my still checkin the temp. Posts: 5,444	All racing two-stroke MX bikes leak a little from the exhaust port/headpipe joint. It's like that so the vibration from the motor doesn't manifest itself into cracks and other bad news on the chamber side. I use to double-up the springs on my CR500, seemed to keep the pipe seated better. If you'll notice the whole chamber is rubber mounted, if it were mounted solid the expansion chamber would be toast in a few hours of riding. __________________ A gun is a tool, Marian; no better or no worse than any other tool: an axe, a shovel or anything. A gun is as good or as bad as the man using it. Remember that.