Bike not wanting to rev past ~5k while driving

[FvnnyL3tt3r1ng]

Also, what is that hole on the left side of the engine that goes into cylinder 1 for....That IS supposed to be there right?

I know you can buy 2 or 3 different types of the rings, what's the difference?

[FvnnyL3tt3r1ng]

Is this issue a common thing on these bikes? If so who wants to buy it? I'd like to ride a bike that likes the way I ride it!

[choneofakind]

Yes that hole is supposed to be there. I think it's for drainage or something since it's on the downhill side of the bike when it's on the side stand. There's an explanation somewhere but I forget. Long story short, that hole is fine. .


I still don't think you were at 2T, but as long as you have the right number of links between marks on your cam gears and you haven't messed with the cams at all, you're good.

[FvnnyL3tt3r1ng]

Originally Posted by choneofakind

Yes that hole is supposed to be there. I think it's for drainage or something since it's on the downhill side of the bike when it's on the side stand. There's an explanation somewhere but I forget. Long story short, that hole is fine. .


I still don't think you were at 2T, but as long as you have the right number of links between marks on your cam gears and you haven't messed with the cams at all, you're good.

I was at 2T in the first set of pictures I put up.... The second post with pictures was at 1T...

[Motofool]

Originally Posted by FvnnyL3tt3r1ng

.......Ok I realize now the position of the markings on the sprockets don't matter at TDC. I counted 33 links as the diagram showed...

I disagree; both sprockets may be off the same degree.

If the marks are off, valves cannot be opening and closing at the right moment respect to the position of the crankshaft.

Remember that this is a four-stroke; hence, it takes two turns of the crankshaft to turn the camshafts once.

There are two TDCs': one between exhaust and intake strokes and another between compression and work strokes.

http://www.animatedengines.com/otto.html

Leak test must be run for each cylinder at a position for which all the valves of that cylinder are closed.

[FvnnyL3tt3r1ng]

Originally Posted by Motofool

Leak test must be run for each cylinder at a position for which all the valves of that cylinder are closed.

Hmmm, now I don't remember if I checked for this even though I knew better.....I'll do it again tomorrow; doesn't take long.

[FvnnyL3tt3r1ng]

Originally Posted by Motofool

I disagree; both sprockets may be off the same degree.
If the marks are off, valves cannot be opening and closing at the right moment respect to the position of the crankshaft.

My rockers were all in the same position as chone's picture

[Motofool]

Originally Posted by FvnnyL3tt3r1ng

.....I'll do it again tomorrow; doesn't take long.

"A hissing noise at the carburetor manifold indicated a leak at the intake valve(s).

Hissing at the exhaust, leaking exhaust valve(s).

Hissing at the oil fill or at the engine breather tube, leaking past the rings."

[FvnnyL3tt3r1ng]

Just did the leakdown test again and cylinder 2 tests fine at ~ 35% leakage but cylinder one is still leaking.

I ran the first test on cylinder one and it showed a moderate leak @ 55% but after running the test a 2nd time (I can't remember if I rotated the engine) the test came out to be 80% leak and as I confirmed the rockers were facing each other I hear the air coming out of the petcock vacuum hose. Does this mean my intake valves are too loose?!?! I did set them towards the looser end maybe I didn't feel them out right?????

I'm going to set them a little tighter and see if that doesn't fix the problem. I hope the valve isn't damaged. The tough part is I had planned a valve clearance alignment the same day I started having the problems!!!! And why would my engine run if the valves were bad then all of a sudden stop working??? I guess that little 2 minute period did them in??? I think a valve job would be way easier than replacing the rings right??

[FvnnyL3tt3r1ng]

Ok, I am still running leak down tests because I am finding interesting things.
You can disregard my previous measurements as the leakage % changes as the air pressure does. I think more air pressure = greater accuracy.

Tell me if I've done something stupid.

I unscrewed the intake valve adjusters on cyl 1 and backed them all the way out in order to eliminate the possibility of air leaking because the valves were not seating. I am right in thinking this correct?

Every time cylinder 1 is either at 1F or 1T it says the engine is fine (low leak ~20%) but air is pouring out of the petcock vacuum. Is this ok? I think the valves are fully seated so therefore the only escape is through the petcock vacuum hose correct?

If the above is true ( engine at 1F and 1T both seal air) is my cylinder fine? Did I just do the adjustment out of spec?

The above post (#169) where I state the leakage changes can be explained by the change in air compression. Each time I am running the test air is leaking and draining the tank on my air compressor. So the less air available will show a higher leak rate, or at least I'm pretty sure of it.

[FvnnyL3tt3r1ng]

Looks like with the rocker lobes facing away at 1T the air holds, with the rocker lobes facing inward at 1T their is a moderate leak.... it might just be the exhaust advancing a little bit......

Whatever the case I am going to try and start her now..... crossed fingers

[FvnnyL3tt3r1ng]

Won't start with new valve adjustments + new plugs.

Won't start with fresh gas + new plugs.

I am done working on this for today.

Looks like I'll be taking it apart sometime this weekend. Wee let the fun begin. I just want the problem to be totally recognizable. It seems one of the valves has gone bad, coincidentally right as I plan to do the alignment.

[FvnnyL3tt3r1ng]

Does anyone have a link to the flywheel diagram with explanations? I just realized how close 1F and 1T were today.....

[Motofool]

Originally Posted by FvnnyL3tt3r1ng

Does anyone have a link to the flywheel diagram with explanations?.....

I don't know of any diagram for the alternator rotor.

However, the timing for the valves is as follows:

Inlet valves open at 30 degrees before Top Dead Center

Inlet valves close at 70 degrees after Bottom Dead Center

Exhaust valves open at 70 degrees before Bottom Dead Center

Exhaust valves close at 30 degrees after Top Dead Center

All valves are open during 280 degrees in a symmetrical way.

http://www.cdxetextbook.com/engines/...ngdiagram.html

Link to original page on YouTube.

Crankshaft is 180 degrees.

Range for ignition timing is as follows:

From 10 degrees before Top Dead Center at 1,300 rpm
to 38 degrees before Top Dead Center at and after 4,000 rpm

[FvnnyL3tt3r1ng]

Can I remove/replace the valves without taking the engine out??

[Motofool]

Yes; the tank and radiator need to be removed and the coolant needs to be drained.

[FvnnyL3tt3r1ng]

Is it ok to replace just one valve or do they need to be as a set?

[Motofool]

One is OK.

[choneofakind]

Make sure you don't drop any small parts into the engine. That can be a real pain in the butt to have to fish parts out of your engine.

[FvnnyL3tt3r1ng]

Originally Posted by choneofakind

Make sure you don't drop any small parts into the engine. That can be a real pain in the butt to have to fish parts out of your engine.

I dropped a rocker arm down into the chain funnel. I can't seem to see it anywhere. Can I just drop the oil filter down and have it fall out?

[FvnnyL3tt3r1ng]

Ok, so I finally took my cylinder head off. I don't know what to look for exactly so I'm hoping these pics will help. Feel free to browse the photobucket album for the other pics. http://s799.photobucket.com/albums/y...90/Motorcycle/

I also found red gasoline when I drained the fuel from the tank going into the carbs. Is this rust? The fuel in the carb bowls were normal color....

[FvnnyL3tt3r1ng]

I am letting the oil drain out of the head before I disassemble the valves...

The cylinder walls are smooth and shiny as can be. The piston rings all seem to be just fine.....

[choneofakind]

Originally Posted by FvnnyL3tt3r1ng

Can I just drop the oil filter down and have it fall out?

should work as long as you're sure that's all that's in there. Just take out the filter and reach around in there to find it.

[FvnnyL3tt3r1ng]

Can I take a wire brush to these piston heads? Is it safe to turn the engine over at this point?

[coughing skunk]

Originally Posted by FvnnyL3tt3r1ng

Is it safe to turn the engine over at this point?

Yes.

The red gas is most likely rust. What does he inside of the tank look like? What does the gas in the carb bowls look like? Rusty gas will not will not ignite correctly and is part of the problem. Make sure to flush the fuel lines and clean the carbs before reassembly. Make sure that tank is clean, and think about sealing it with red kote or a similar product. I have had success with por15 as well, my roommate swears by kream..

Also, before reassembly make sure the gasket surfaces are completely clean!! Use some paint stripper on the stuck on gasket and wait a couple of minutes then scrub with a nylon brissled brush. No matter what you do, do not score these mating surfaces.

[FvnnyL3tt3r1ng]

Originally Posted by coughing skunk

Yes.

The red gas is most likely rust. What does he inside of the tank look like? What does the gas in the carb bowls look like? Rusty gas will not will not ignite correctly and is part of the problem. Make sure to flush the fuel lines and clean the carbs before reassembly. Make sure that tank is clean, and think about sealing it with red kote or a similar product. I have had success with por15 as well, my roommate swears by kream..

Also, before reassembly make sure the gasket surfaces are completely clean!! Use some paint stripper on the stuck on gasket and wait a couple of minutes then scrub with a nylon brissled brush. No matter what you do, do not score these mating surfaces.

It's ok to turn the engine over with the tensioner removed?

I think the inside of the tank has flakes of rust floating I'm not sure. I will def. get the tank cleaned out once I have her running again. The fuel in the carbs was fine.

How do I clean the piston heads? Is it too sensitive to use a wire brush?

[coughing skunk]

You can use a wire brush to clean the piston heads. Just be careful and remember it is way easier to take off more carbon than to put back some metal. I would suggest soaking the bores/piston tops with seafoam to help break up the carbon if you do decide to remove it.

I'm not totally familiar with the internals of this motor, but it should be safe to turn the engine with the tensioner removed. Just don't let the cam chain fall into the block.

Cleaning the tank is easy!. Check out this method.

[FvnnyL3tt3r1ng]

Learning how to use the valve spring compressor tool now.....seems way harder than I thought it would be... I put it on (fit over two, but not over one) compressed it many times with much resistance, and nothing happened.

So far the carbon is coming off decently well.

[coughing skunk]

Look real good. While you've got the pistons out you mine as well check if they're within spec. You should do new rings and hone the cylinders before reassembly as well.

When using the valve compressor are you able to push the valve up towards you while the spring is compressed? That is the only way the colletes will come out.. Got some pics?

[FvnnyL3tt3r1ng]

Originally Posted by coughing skunk

Look real good. While you've got the pistons out you mine as well check if they're within spec. You should do new rings and hone the cylinders before reassembly as well.

When using the valve compressor are you able to push the valve up towards you while the spring is compressed? That is the only way the colletes will come out.. Got some pics?

I am gonna order new gaskets, o-rings, and valves as of now. Do I need new rings and to hone the cylinder? What is the process of honing the cylinder?
I'm on a budget and doing this strictly to get the bike back up and running as I am lowwww on cash and in need of a job.

[FvnnyL3tt3r1ng]

New set of rings are $41...

Is it possible my low compression was mostly due to the carbon buildup on the pistons?

[FvnnyL3tt3r1ng]

Originally Posted by coughing skunk

Look real good. While you've got the pistons out you mine as well check if they're within spec. You should do new rings and hone the cylinders before reassembly as well.

When using the valve compressor are you able to push the valve up towards you while the spring is compressed? That is the only way the colletes will come out.. Got some pics?

I didn't try to push the valve up maybe that's what I'm missing....

[FvnnyL3tt3r1ng]

Update: Ok looks like I'm not gonna be ordering much since everything is ridiculously expensive. I may try to reseat the valves I have at the bike shop but I cannot afford all new valves at the moment.

[Motofool]

Originally Posted by FvnnyL3tt3r1ng

New set of rings are $41...

Is it possible my low compression was mostly due to the carbon buildup on the pistons?

No; carbon build up increases the compression readings, since the volume in the combustion chamber gets reduced.

However, carbon can build up between the rings and their piston's seats, compromising their elasticity to press against the walls of the cylinder and to slide up and down within the seats.

Did you put some fuel inside the chambers to see what valve leaks?

"Last thing. We want to test our work. Turn the head so the combustion chamber is up and level. Fill the chamber with solvent or gas. Let it set a minute or two and then shine a light up the exhaust and intake ports. Look for leaks or wetness. There should be none. If there is, take the offending valve back apart and relap it. Then put it together and test it again. The solvent will find the slightest leak. We want NO leaks."

http://www.dansmc.com/valve.htm

http://www.dansmc.com/pistons.htm

http://www.dansmc.com/hone_cyl.htm

[FvnnyL3tt3r1ng]

Originally Posted by Motofool

No; carbon build up increases the compression readings, since the volume in the combustion chamber gets reduced.

However, carbon can build up between the rings and their piston's seats, compromising their elasticity to press against the walls of the cylinder and to slide up and down within the seats.

Did you put some fuel inside the chambers to see what valve leaks?

"Last thing. We want to test our work. Turn the head so the combustion chamber is up and level. Fill the chamber with solvent or gas. Let it set a minute or two and then shine a light up the exhaust and intake ports. Look for leaks or wetness. There should be none. If there is, take the offending valve back apart and relap it. Then put it together and test it again. The solvent will find the slightest leak. We want NO leaks."

http://www.dansmc.com/valve.htm

http://www.dansmc.com/pistons.htm

http://www.dansmc.com/hone_cyl.htm

I will do this and hopefully it will save me a lot of money. The good thing is all the valves *appear* to be straight and so maybe they just require a relap. I will check all the measurements I can tomorrow, right now I am degreasing the cylinder head for the 2nd time as I left the valves in the first time in a rush. There was a lot of gunk and carbon in the exhaust and intank ports so at the very least I'll be able to see any leaks better now. From my leak down test I'm pretty sure I narrowed it down to one of cylinder 1s intake valves.

Should I lap all the valves?

[Motofool]

I would do only what is needed, based on your current situation.

Follow the old principle: If it is working, don't fix it.

Rather than putting a lot of money on an old bike, I would bike a newer bike with minor problems, or just find a replacing used engine.

The strong carbon build up comes from using non-synthetic oil and running the bike for short periods and low speeds, not reaching and keeping high temperatures.

How did you clean the pistons?

[FvnnyL3tt3r1ng]

Right side is front(exhaust), left side is rear (intake)


The gunk exhaust side


Cylinder 1 intake valve (1)


Cylinder 1 intake valve (2)

[FvnnyL3tt3r1ng]

Originally Posted by Motofool

I would do only what is needed, based on your current situation.

Follow the old principle: If it is working, don't fix it.

Rather than putting a lot of money on an old bike, I would bike a newer bike with minor problems, or just find a replacing used engine.

The strong carbon build up comes from using non-synthetic oil and running the bike for short periods and low speeds, not reaching and keeping high temperatures.

How did you clean the pistons?

Well it has gotten synthetic since it's been mine. I cleaned the pistons by soaking them in degreaser and then spraying them with brake cleaner and scraping the carbon off with a plastic wedge.

Hoping this will fix it

[Motofool]

Wow, you have a lot of cleaning to do.

Check that those rings are loose in the pistons.

Try not scratching the aluminum surfaces, especially the valve's seats.

Great work, Justin !

[FvnnyL3tt3r1ng]

Originally Posted by Motofool

Wow, you have a lot of cleaning to do.

Check that those rings are loose in the pistons.

Try not scratching the aluminum surfaces, especially the valve's seats.

Great work, Justin !

They're all loose

And thanks!