Sportster odd engine noise

Help,
Been chasing this noise since we updated to the 1250. Coming from the front cylinder, sounds like a clackety sound not quite a knock . it is more pronounced when the engine drops below the idle rpm like when you go to pull out from a stop sign and as far as i can tell it basically goes away at road speed, no indication of it just the normal tick sound. We thought at first we had a lifter going bad so we swapped them out. Still have the problem. At normal idle speed you know something is not quite right but it is not as pronounced. I read on another post somwhere if the exhaust pushrod were mistakenly put into the intake that it would make some wierd noises.Right now that is what i am thinking. Also this engine has the stock cams installed an the cam cover has never been taken off.Any suggestions here would be greatly appreciated.
Tim

The intake & exhaust pushrods are not the same length, the intakes being slightly shorter, so if you got 'em mixed up, that could be your problem.

Couple other things which come to mind is the design of the pistons & if the cylinders were properly matched to them. Normally forged pistons are used in that application & they have to be set up "loose" since they "grow" as they heat up - they'll rattle like a bucket of bolts cold. Stock pistons are cast using a different alloy & they don't expand like forged.

And the ONLY way to get the piston-to-wall clearance right is to use torque plates on the cylinders. They'll be out-of-round just sitting on the workbench but you don't care about that - what you want to know is what the exact dimensions are when they're installed - torque plates duplicate the stresses put on the cyls. when they're installed & the heads are torqued down.

Thanks Art,
These are forged pistons and they are installed in nik-a-sil coated aluminum barrels . they were supposed to be matched set, but who knows ,Actually CPpistons and Millenium barrels(Revolution Performance). Hot or cold this noise is always there and it seems to be more rpm related the way it sounds to me.The more rpm the quieter
Thanks Tim

If they came from NRHS, no doubt they were matched - from someone else I couldn't say. (I've been to NRHS & know their work).

Then your thoughts about an intake pushrod being where an exhaust pushrod should be & vice-versa may very well be right - sounds valvetrain related & once an engine with forged pistons gets warmed all the way up, the piston "slap" sound should be gone.

At the risk of starting a "dreaded oil thread", I need to make a point about those "Nik-A-Sil" cylinders - you may recall Chevy tried that & it didn't work - remember the Vega? Cylinders worn out-of-round in 30,000 miles & blue (oil) smoke out the tailpipe? Porsche did get the process to work, but in a liquid-cooled engine, not air-cooled.

H-D aluminum cylinders "grow" as they heat up & with forged pistons too, the piston-to-wall clearance WILL change. And due to the basic V-Twin design, the pistons try to turn sideways in the cylinders - there's a "rocking action" which tends to wipe oil right off the cylinder walls. You can't stop the wear, but you can sure slow it down, with precise machine work & a high quality heavy grade oil. You'll never see the day I use anything less than SAE 50 oil in a Sportster engine - 60 weight in hotter weather & I even have some SAE 70. Multi-grade car oils will get wiped right off the cylinder walls in a H-D engine & the Nik-A-Sil coating will not hold up.

NRHS has gone to Axtell for 1250 cylinders & you can get both ductile iron & aluminum with sleeves - because of the problems with the Nik-A-Sil process. But you can still make the Nik-A-Sil cyls. last a good while - IF you use a high quality straight-weight oil so there's always a good coating between the pistons & the cylinders.

Thanks, Chuck !! Busy, busy, busy with all kinds of crazy stuff, but I do have to check in periodically to see what y'all are up to

thanks again Art, As for the nik-a-sil cylinders i guess we will see,they have a lifetime warrenty.As for the oil i use strictly Mobil 1 vtwin 20w50 every 2500 miles. Also if your interested check out the Revolution Performance web site . Performance Parts for Harley-Davidson and Buell – Revolution Performance
Tim

Art,
When i checked the pushrods on the front head every thing was correct but when i pulled the front push rod and blue compressed air thru i got some kind of sludge out of it, go figure , oil has been changed since day 1 every 2500 hundred miles with filter. Put it back together and changed oil and ran it and sure enough the noise has disappeared.

Glad it was that simple, Tim !!

Some comments on oil though - I'm not a salesman for Red Line Oil & stand to gain nothing if you use it, but when I tested Mobil I in a Sportster, the oil temps were higher than I'd ever seen before & taking a Sportster-based (race) engine apart after using Red Line for a year, there was no sludge, no carbon deposits & no measureable wear - cleanest engine I've ever seen.

People say synthetic oils can handle higher temps than conventional & while that's true, the "additive package" is the primary concern - friction modifiers, detergents, etc. do not last long in a hot engine & "sludge" forming is an end result - the additive package can be useless in 1000 miles. Interesting tidbit - I spoke @ length with a chemical engineer @ Mobil & she said a guy in the Dept. who rides a Harley uses Valvoline SAE 50 (conventional) Racing Oil - same as I started using in 1969 & still do in some applications. The guy uses Mobil I in his car, but not in his bike & that really says something.

The Red Line I use in some applications carries a multi-grade rating (20W50, 20W60, etc.) but it's not multi-grade - it can just carry the designation since it can pass the "cold-flow" tests. Red Line 20W50 is actually SAE 50 straight-weight, 20W60 is SAE 60, etc. (which will flow as well as a 20 weight cold) & the formulation is VERY different from Mobil I - which I will never use again. A lot of people like it & that's fine, but after using several different oils in several different applications for 40 years, the only oils I'll put in a Harley (or any other air-cooled engine) are straight-weight Valvoline Racing oil or Red Line synthetic.

One more thing is that there are 2 versions of the Valvoline - the newer silver/gray jug for applications with a catalytic converter & the "not street legal" black jug original formula - which is what you want for a Harley. The difference is the anti-wear agents in the original will mess up a cat converter as they burn off during the normal combustion process - but a H-D engine needs those additives.

Art ,
The oil i changed to after this was Klotz synthetic straight 50w for v-twin. Any thoughts or comments.
Tim

Tim, I'm not familiar with the Klotz brand, but I did look around the website a bit. I like the SAE rating & know a "straight-weight" synthetic oil can flow better cold than a conventional oil (including multi-grade), but there's not much detail on the Klotz site & papers like these on Red Line's site give far more info:

http://www.redlineoil.com/whitePaper/motoroils.pdf

http://www.redlineoil.com/pdf/4.pdf

I'm not a chemical engineer but I used to work for one & while real-world testing is far better than lab tests like the "4-ball wear test" one manufacturer brags about (irrelevant to a H-D engine), the formulation of any given product for a given application is crucial.

Not to say that Klotz doesn't make excellent products, I just don't have enough info. I'll stick with what I know works until I see proof that something else works better. Scored cylinder walls, trashed pistons, etc. I can't afford & I learned my lesson trying something (Mobil I) that a lot of people said was great.

Check oil temps & if possible, take the engine apart - get the micrometers out to see what's been going on inside. Theory is one thing, but wear patterns on the parts may tell you something quite different.