5hp flathead smoking?

jbe24jg

jbe24jg

New Member
#1
#1
I built this wards/gilson for last years build off and I put this 5hp briggs in it. I honed the cylinder put new rings it did all the gaskets but it smokes like a :censure:. Its aluminum bore and sounds killer. The first oil change there were a few little specs of metal but nothing major and now the oil is fairly clean. Here's a video. When you first starts it hardly smokes, but as it runs it smokes more and more.
Mini bike smoking? - YouTube
 
creia

creia

#2
#2
Sounds like the cylinder wall is excessively worn (over-sized, tapered, and/or out of round) and oil is getting past the rings.
Before you installed the new rings and honed:
1. Did you check the piston to cylinder wall clearance?
2. Did you check the ring end gap?
Michael
 
creia

creia

#4
#4
directdrive said:
I read somewhere you're not supposed to hone cool bores.
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Not correct. The preferred practice is to always hone when installing standard (cast iron) rings even in "Kool Bores" (aluminum cylinder). It is imperative, however, that the correct TYPE of honing stones are used, as they are different grit for the aluminum bores and the iron bores. If you use the wrong ones in a Kool Bore you will really damage the cylinder wall. What you might be referring to is when you install "chrome" rings in a Kool Bore- In that case Briggs states NOT to hone.
Michael
 
5horsebriggs

5horsebriggs

New Member
#5
#5
creia said:
Not correct. The preferred practice is to always hone when installing standard (cast iron) rings even in "Kool Bores" (aluminum cylinder). It is imperative, however, that the correct TYPE of honing stones are used, as they are different grit for the aluminum bores and the iron bores. If you use the wrong ones in a Kool Bore you will really damage the cylinder wall. What you might be referring to is when you install "chrome" rings in a Kool Bore- In that case Briggs states NOT to hone.
Michael
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I though you must use chrome rings?'i honed and used Crome rings, mabye thats why my cylinder wall got torn up
 
creia

creia

#6
#6
5horsebriggs said:
I though you must use chrome rings?'i honed and used Crome rings, mabye thats why my cylinder wall got torn up
Click to expand...
Not correct. You do not "HAVE TO" use chrome rings. But if you do, NO HONING as per Briggs specs. In addition, did you use honing stones specifically made for aluminum? It sounds like you might have used stones made for a steel lined cylinder and THAT is what probably "torn up" your cylinder wall!?:doah:
Michael
 
5horsebriggs

5horsebriggs

New Member
#7
#7
creia said:
Not correct. You do not "HAVE TO" use chrome rings. But if you do, NO HONING as per Briggs specs. In addition, did you use honing stones specifically made for aluminum? It sounds like you might have used stones made for a steel lined cylinder and THAT is what probably "torn up" your cylinder wall!?:doah:
Michael
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I didnt hone it i bought it from 125 and it was already honed
 
directdrive

directdrive

New Member
#8
#8
American Powersport does sell chrome Wiseco pistons. What threw me was it states you use Raptor3 rings with them. I was under the impression chrome piston/chrome rings with kool bores. Michael is right, I read that the wrong honing stones will gall the cylinder walls. You have to use fine stones specific for the kool bores.I learned something. Thanks.
 
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creia

creia

#9
#9
directdrive said:
American Powersport does sell chrome Wiseco pistons. What threw me was it states you use Raptor3 rings with them. I was under the impression chrome piston/chrome rings with kool bores. Michael is right, I read that the wrong honing stones will gall the cylinder walls. You have to use fine stones specific for the kool bores.I learned something. Thanks.
Click to expand...
You are confusing chrome (plated) PISTONS and chrome RINGS. With an aluminum cylinder ("Kool Bore") engine the former is an absolute MUST , while the latter is an OPTION.
Sidebar- Chrome RINGS are basically used as a "band aid" to extend the lifespan of a "Kool Bore" engine with a worn bore that will help to increase compression and reduce oil consumption. It is a cheap, however temporary, alternative to re-boring oversize and having to purchase and oversize piston/ring set. It is simply buying you a little more time.
Michael
 
125ccCrazy

125ccCrazy

Well-Known Member
#11
#11
how were the valve guides? if the intake is excessively worn you my be sucking oil past the stem... also if the rings are not installed correctly you could be pushing oil into the chamber..

5horsebriggs said:
I didnt hone it i bought it from 125 and it was already honed
Click to expand...
I thought that was determined you didn't check the ring end gaps and used a non chrome piston?
 
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5horsebriggs

5horsebriggs

New Member
#12
#12
125ccCrazy said:
how were the valve guides? if the intake is excessively worn you my be sucking oil past the stem... also if the rings are not installed correctly you could be pushing oil into the chamber..


I thought that was determined you didn't check the ring end gaps and used a non chrome piston?
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That's what i thought but reading what crea said added to my
Suspicion lol
 
125ccCrazy

125ccCrazy

Well-Known Member
#13
#13
5horsebriggs said:
That's what i thought but reading what crea said added to my
Suspicion lol
Click to expand...
as bad as the piston and wall looked either the end gaps were too tight, a ring was broken during installation or the piston galled to the cylinder from lack of lubrication, extreme heat, using a non chrome piston or all of the above....
 
jbe24jg

jbe24jg

New Member
#15
#15
I did use the correct grit honing stones however and used cast iron rings and Im sure that I counter rotated to rings. I didn't check the ring gap or cylinder bore. That valve have the correct clearance but I'm not sure about the guides. It runs like a top and always starts and I really dont want to scrap it for a predator.
 
creia

creia

#16
#16
jbe24jg said:
I didn't check the ring gap or cylinder bore.

You really HAVE to do that before installing new rings. If the cylinder wall is worn past specs, tapered, or out of round, installing new rings will not accomplish anything and it will still be an oil burner (smoke).
Michael
Click to expand...
 
Richard Trotter

Richard Trotter

#17
#17
Before tearing the motor down, try running a lower oil level. Filling the crankcase clear full works ok if you never rev over 3600 RPM. At higher RPM, a full motor will try to push oil out the breather tube and into the carb. Remove 1/2 cup and try it again.
 
creia

creia

#18
#18
Richard Trotter said:
Before tearing the motor down, try running a lower oil level. Filling the crankcase clear full works ok if you never rev over 3600 RPM. At higher RPM, a full motor will try to push oil out the breather tube and into the carb. Remove 1/2 cup and try it again.
Click to expand...
Great suggestion Richard. That is the accepted practice on the Briggs Raptor engines as well. It appears in the video he posted, however, that the engine is even smoking during idle and low rpm?:shrug:
Michael
 
jbe24jg

jbe24jg

New Member
#19
#19
in the video I hardly rev it over 2000 due to the awful screech of the starter clutch (thats next on the to do list). How high should the oil be in relation to the oil fill hole?
 
Clayon

Clayon

#20
#20
Very good info here. :thumbsup: Another possibility, did you check the cylinder for ovality? Use a telescoping gauge and micrometer, measure in 4 spots 90 degrees from each other. That will tell you if your cylinder is oval.

Edit: Sorry, I missed seeing that Michael already mentioned checking if your cylinder is out of round.

Sent from my iPhone using Tapatalk
 
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