103 Upgrade Gone Wrong
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Joined: Dec 2007
Posts: 12,084
Likes: 829
Want to help you, but without compression test numbers, and a leakdown test, along with any cylinder head flow numbers, I'm at a loss at this point.
Could be so far out of tune, ie timing, fuel curve, that is what is causing your lack-luster performance.
Mighty easy to push out 105-110 hp and 115-up ft/lbs from a tame 103"er.
Scott
Could be so far out of tune, ie timing, fuel curve, that is what is causing your lack-luster performance.
Mighty easy to push out 105-110 hp and 115-up ft/lbs from a tame 103"er.
Scott
Want to help you, but without compression test numbers, and a leakdown test, along with any cylinder head flow numbers, I'm at a loss at this point.
Could be so far out of tune, ie timing, fuel curve, that is what is causing your lack-luster performance.
Mighty easy to push out 105-110 hp and 115-up ft/lbs from a tame 103"er.
Scott
Could be so far out of tune, ie timing, fuel curve, that is what is causing your lack-luster performance.
Mighty easy to push out 105-110 hp and 115-up ft/lbs from a tame 103"er.
Scott
HDF Community Team
Joined: Jun 2006
Posts: 12,776
Likes: 2,607
From: san antonio
In addition to compression and leakdown test data, it would also be good to know who bored cylinders and fitted pistions (you should have been provided a sheet showing the four axis measurement at top, center and bottom of bore), KB pistons but which ones? hypereutectic or forged? domed or flat top?, and who ported the heads and what was done, i.e., were the heads decked? what is the chamber volume? What head gasket thickness?
The compression test data won't help without the details of the build. This sort of diagnosis via the internet is difficult at best, so the more detail you can provide the more help you can expect.
Last edited by djl; Nov 7, 2011 at 11:09 AM.
Cruiser
Joined: Oct 2011
Posts: 164
Likes: 0
From: Keyser, WV
In addition to compression and leakdown test data, it would also be good to know who bored cylinders and fitted pistions (you should have been provided a sheet showing the four axis measurement at top, center and bottom of bore), KB pistons but which ones? hypereutectic or forged? domed or flat top?, and who ported the heads and what was done, i.e., were the heads decked? what is the chamber volume? What head gasket thickness?
The compression test data won't help without the details of the build. This sort of diagnosis via the internet is difficult at best, so the more detail you can provide the more help you can expect.
The compression test data won't help without the details of the build. This sort of diagnosis via the internet is difficult at best, so the more detail you can provide the more help you can expect.
Good luck
Have you checked for sumping?
In addition to compression and leakdown test data, it would also be good to know who bored cylinders and fitted pistions (you should have been provided a sheet showing the four axis measurement at top, center and bottom of bore), KB pistons but which ones? hypereutectic or forged? domed or flat top?, and who ported the heads and what was done, i.e., were the heads decked? what is the chamber volume? What head gasket thickness?
The compression test data won't help without the details of the build. This sort of diagnosis via the internet is difficult at best, so the more detail you can provide the more help you can expect.
In addition to compression and leakdown test data, it would also be good to know who bored cylinders and fitted pistions (you should have been provided a sheet showing the four axis measurement at top, center and bottom of bore), KB pistons but which ones? hypereutectic or forged? domed or flat top?, and who ported the heads and what was done, i.e., were the heads decked? what is the chamber volume? What head gasket thickness?
The compression test data won't help without the details of the build. This sort of diagnosis via the internet is difficult at best, so the more detail you can provide the more help you can expect.
One additional point, I use an LCD oil level and temperature dipstick on my bike, which since the build, has developed a leak, pushing oil into the display area of the dipstick head. Didn't matter much to me since the display stopped working some time back and I planned on replacing it anyway. Could this be because of increased pressure in the crankcase caused by a ring failure? I guess the compression check will verify that, huh? You guys are making me look at things a lot closer. Thanks, ...Don
Last edited by gnirtsnod; Nov 7, 2011 at 01:46 PM.
Ultimate HDF Member
Joined: Feb 2007
Posts: 7,663
Likes: 7
From: Northeast Ohio
There is just so many things in your information that lead to more questions. First, the tune is waaaaay off if only getting 29mpg and having to baby it to get into the 30's. Most 120 inch engine still easily get 40+ mpg so your 103 has a real problem. A way rich tune will wash down the cyl walls, not allowing the rings to seat and this then leads to blow by which you indicate by the statement of oil out the exhaust or possibly unburnt fuel. Also by the pressure in the crankcase. Pull your dipstick, smell the oil, is it black? Smell like gas? - Rich tune. Get the tests done that others have indicated to at least have a starting point.
Cruiser
Joined: Jul 2011
Posts: 210
Likes: 1
From: Pacific Northwest
Blue smoke means burning oil. Gray smoke means rich mixture.
Last edited by pnw_hd_rider; Nov 8, 2011 at 09:45 AM.
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Ultimate HDF Member
Joined: Feb 2007
Posts: 7,663
Likes: 7
From: Northeast Ohio
How would blow by or rich mixture have anything to do with oil coming out the exhaust? Burning oil has nothing to do with compression rings. Oil scraper rings (in the bottom groove) don't have to 'seat' the way compression rings do. Excessive piston wash does not effect the ability of oil scraper rings to do their job.
Blue smoke means burning oil. Gray smoke means rich mixture.
Blue smoke means burning oil. Gray smoke means rich mixture.
Lets see if I can get this right. You are right, blue smoke out the exhaust means burning oil, but grey smoke indicates water vapor (this was not a water cooled v-rod)
, and black smoke means unburnt fuel.You are correct, oil scraper rings do not seat the same as compression rings, but if the cyls are washed down with fuel, there is initially no lubrication which will allow the walls to be glazed smooth and the oil control rings will not work either, as well a the compression rings allowing blowby which will increase crankcase pressure resulting in oil being forced throught he intake system in the cyls for burning and also oil not being scraped off the cylinder walls, thus being being burned. If crankcase pressure is high enouhg oil can even be pushed down through the valve guides and burnt. Oil scraper (oil control) rings are designed to leave a certain amount of oil on the cylinder wall with each pass, this lubricates the compressin rings, the pistons and prevents seizure.
Also excessive piston wash as you call it will eventually lead to piston skirt wear and piston slap, which leads to rocking of the pistons which leads to poor ring seating and further oil problems.
Hmmmmm,
Maybe I have had it wrong all these years.
I think not - the easiest way to damage a new build is to tune it too rich, it will lead to an engine that performs poorly due to compresion and leakdown issues and to one that will use oil.
There are other things that also could be wrong such as a compression ring in upside down. As with any internet diagnosis, without all the facts, all we can do is throw out possibilities.
OK, I am ready to learn more !
