I have a mild 196cc with 0.020" billet rod, ft honda 1mm rings, billet 6619 fw,18lb springs as well as the usual stage 1 stuff. I noticed that if I free rev the bike with the wheel off the ground there is small amount of blue smoke. Is this from the rings not sealing, sloppy valve guide or another cause? I would assume if it was rings it would smoke even at idle but this is only under a hard rev.
Blue smoke on hard rev
- Thread starter MDDoodleBeast
- Start date
- Tags blue hard rev smoke
Might be rings not sealing, could be too much oil foaming up and getting sucked into the carb ( depending on your induction system )
Its really hard to screw these things up if you honed it and assembled it correctly.
Get a load on it and run it.
These narrow rings seal well but you have load them down. ( really all builds need to break in under a load for best seal )
I build engines out of junk with used rings and gaskets.
I run them up on a load and they seal back up.
One on my snow blower was seized for a year, but its a decent running engine with no smoke....
Hmm...
You could get a oil control ring wedged in the groove ( but the engine will feel very tight ) from improper assembly.
Once the ring is damaged and the liner scored they will smoke a bit but they still run.
Its really hard to screw these things up if you honed it and assembled it correctly.
Get a load on it and run it.
These narrow rings seal well but you have load them down. ( really all builds need to break in under a load for best seal )
I build engines out of junk with used rings and gaskets.
I run them up on a load and they seal back up.
One on my snow blower was seized for a year, but its a decent running engine with no smoke....
Hmm...
You could get a oil control ring wedged in the groove ( but the engine will feel very tight ) from improper assembly.
Once the ring is damaged and the liner scored they will smoke a bit but they still run.
I may switch back to conventional and continue to try and seat the rings further. I have maybe 7 hours of runtime on this build 4 of which were 300ft dirt drags. I am getting a 22mm mikuni for Christmas as well as an hour/tach so that would rule out the carb issue. Everything spins freely and I clocked the rings correctly. Can't remember if I put the numbers on the rings up or down so that also could be it. May buy new rings and redo break in if the smoke persists. Hate to build a strong motor and have it leak and not take advantage of the compression.
If it runs good just live and ride.
The oil control on the Honda piston is so good its very dry on the top of the liner.
I add a bit of oil for lubricity to my fuel and remove the oil seal from the intake.
How much blow by?
It might seal up yet.
Clocking the rings is not as big a deal as its made out to be.
It does not hurt anything
Eventually they rotate around the piston in a random manner.
Sometimes they line up and you might notice a puff of smoke in a high hour engine.
On big diesels with proper instrumentation you can see a temperature spike and drop as the rings line up and drift apart.
The oil control on the Honda piston is so good its very dry on the top of the liner.
I add a bit of oil for lubricity to my fuel and remove the oil seal from the intake.
How much blow by?
It might seal up yet.
Clocking the rings is not as big a deal as its made out to be.
It does not hurt anything
Eventually they rotate around the piston in a random manner.
Sometimes they line up and you might notice a puff of smoke in a high hour engine.
On big diesels with proper instrumentation you can see a temperature spike and drop as the rings line up and drift apart.
If your end gap exceeds .012 you will start to get some significant blow by.
if you got that with a stock ring you need to file fit and over size and try and get around .005 ( less gets risky )
Upside down ring was suggested to explain the smoke and that sounds reasonable.
But if it still runs good who cares?
That scraper ring upside down might even improve the lubrication of the top liner.
Clone bore Honda bore not really important as long as its round, clean and that gap is right.
Once you hit that .012 number your as loose a reasonable person should build an engine at.
Loose is fast, but hard to seal, so you want the file fit ring.
Tight gap on the rings is risky, but if your loose you can come under the factory spec a little on the 1mm ring set.
Where clones fall down is the bore is not square to the deck.
Sometimes the bore is tapered or barrel shaped.
You need to check these against the Honda OEM spec for new parts and decide if you have a bad block and need to bore it oversize.
But if you have a decent block and its used and starting to get a bit sloppy that's actually a good thing.
Loose does not blow up near as often as tight.
As long as your rings seal up good, your guides are tight and you have clearance in your rod ( new is almost always tight and risky ) you can get lots of power from a clone on the cheap and it will not blow up on you.
Even outside the spec with a galled up crank cleaned, some scratches in the bore and rings in the .008 -.012 range you can still have a great running engine that should not be too leaky or smokey.
I made some engines I still use as daily utility engines that were blown up junk.
And they outperform because they tend to have some better parts in then like the Z4M piston or 14cc heads.
if you got that with a stock ring you need to file fit and over size and try and get around .005 ( less gets risky )
Upside down ring was suggested to explain the smoke and that sounds reasonable.
But if it still runs good who cares?
That scraper ring upside down might even improve the lubrication of the top liner.
Clone bore Honda bore not really important as long as its round, clean and that gap is right.
Once you hit that .012 number your as loose a reasonable person should build an engine at.
Loose is fast, but hard to seal, so you want the file fit ring.
Tight gap on the rings is risky, but if your loose you can come under the factory spec a little on the 1mm ring set.
Where clones fall down is the bore is not square to the deck.
Sometimes the bore is tapered or barrel shaped.
You need to check these against the Honda OEM spec for new parts and decide if you have a bad block and need to bore it oversize.
But if you have a decent block and its used and starting to get a bit sloppy that's actually a good thing.
Loose does not blow up near as often as tight.
As long as your rings seal up good, your guides are tight and you have clearance in your rod ( new is almost always tight and risky ) you can get lots of power from a clone on the cheap and it will not blow up on you.
Even outside the spec with a galled up crank cleaned, some scratches in the bore and rings in the .008 -.012 range you can still have a great running engine that should not be too leaky or smokey.
I made some engines I still use as daily utility engines that were blown up junk.
And they outperform because they tend to have some better parts in then like the Z4M piston or 14cc heads.
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Ring end gap was 0.004" prior to piston installation. It is a genuine honda t3 flattop zm4 with honda rings in a clone motor. Once again not entirely sure whether the rings were installed numbers up or down. However I believe the motor makes pretty good power for what it is and the aftermarket cam and carb I have coming should get me where I need to be.
I understand that you are saying the parts are not perfectly compatible and am in no way taking offense to what you have said. I prefer criticism so I can become better on the next build. I know you will consider this idiotic and abuse but I wanted to show you what I was talking about . Doodlebug burning oil and shooting flames - YouTube
The engine sounds lazy, like the cam is out one tooth.
I have not seen a central machine clone in????
A decade I would guess, I am not saying they do not exist anymore but central machine was one of many communist era factories that made all kinds of different engines.
Some were privatized and became new companies and some just closed up.
Your first clue the central machine products were off was the extra thick liner they used ( I think it was a left over from some other product ).
And the soft lifters that would wear out ( also a rotation issue at play ).
You know now that I think about it I have a central machine in the shed, I bought it on a 25 dollar loony deal as a return ( had a bad crank and worn out cam/lifter ).
I bought it for the electric start kit and ended up just tossing some parts at it and guess what its decent pump engine ( just need to find a pump to screw on to it ).
Its a blue cone too, and the emission data suggests it was made in 03 or something so I guess it was sitting around at tool town for decade before being sold and blowing up.
Repair cost ZERO, I never even changed the gaskets, but I did modify the pull start to except a John deere gater water pump pulley and now it can run an alternator and water pump if I ever find one.
This is the internet fellows so anyone can say and prove anything.
I have not seen a central machine clone in????
A decade I would guess, I am not saying they do not exist anymore but central machine was one of many communist era factories that made all kinds of different engines.
Some were privatized and became new companies and some just closed up.
Your first clue the central machine products were off was the extra thick liner they used ( I think it was a left over from some other product ).
And the soft lifters that would wear out ( also a rotation issue at play ).
You know now that I think about it I have a central machine in the shed, I bought it on a 25 dollar loony deal as a return ( had a bad crank and worn out cam/lifter ).
I bought it for the electric start kit and ended up just tossing some parts at it and guess what its decent pump engine ( just need to find a pump to screw on to it ).
Its a blue cone too, and the emission data suggests it was made in 03 or something so I guess it was sitting around at tool town for decade before being sold and blowing up.
Repair cost ZERO, I never even changed the gaskets, but I did modify the pull start to except a John deere gater water pump pulley and now it can run an alternator and water pump if I ever find one.
This is the internet fellows so anyone can say and prove anything.
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I was the first person in Canada to import and sell the Z4M piston.
I had them before the Honda dealer network here and I got a great deal of pleasure playing mind games with the dealer about where I got them and how I could sell them for less than a third the price of the long skirt 1mm rings they had in stock.
There is nothing wrong with them, they do not cause any problems in Honda or clone 196cc engines and if installed correctly they a great upgrade for any engine.
I had them before the Honda dealer network here and I got a great deal of pleasure playing mind games with the dealer about where I got them and how I could sell them for less than a third the price of the long skirt 1mm rings they had in stock.
There is nothing wrong with them, they do not cause any problems in Honda or clone 196cc engines and if installed correctly they a great upgrade for any engine.
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