Question about 2004 Harley Davidson XL 1200 C Sportster Custom

1 Answer

Harley twincam 120 sounds like spark knock on accel after reaching 2500 rpms

Just installed 120 kit /happend after dyno was done / tryed new cams and lifters / still same noise

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  • Harley Davidson Master
  • 41,865 Answers

Hi Tom, and the usual suspects are:
1. Fuel octane rating too low.
2. Faulty spark plugs.
3. Incorrect spark plug for the kind of service.
4. Excessive carbon deposit on piston head or in combustion chamber.
5. Ignition timing advanced due to faulty sensor inputs (MAP, CKP, CMP)
Good luck.

Posted on May 28, 2015

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Posted on Jan 02, 2017

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SOURCE: new pips

No.Although, it is a common practice to de-tune bikes at the factory so that they meet emissions requirements. All new injected HD's can expect a 4-6% increase in horsepower and 2-3% increase in torque just by dyno tuning the bike straight off the showroom floor. If you're riding a Low with a carb, then you do not need to have it re-jetted for slip-on's. If you're changing the exhaust from where it bolts to the engine, then yes you should. Dyno tuning is not as useful on carbureted bikes compared to injected ones, in fact I could tune a carbureted Low just as easily with an Exhaust Gas Analyzer as a dyno and save you $300. You're probably not that interested in minor differences in horsepower if you're doing slip-ons rather than a whole Screaming Eagle Stage 2 kit. Bolt 'em on and ride...

Posted on Nov 20, 2008

  • 218 Answers

SOURCE: 2003 Harley Davidson Sportster 1200 Custom Tachometer kit

The only idea that i can come up with is that you dont have a good ground..or the guage was bad when you bought it..i hope this..Keith

Posted on Jul 02, 2009

REDOIL
  • 355 Answers

SOURCE: knocking sound during acceleration

I WOULD CHECK TIMNG AND MAKE SHERE YOUR GETING OIL TO UPPER END WHEN THEY DID UPGRADE DID THEY UPGRADE CAM BEARING TO IF NOT YOU COULD HAVE DONE MOTOR DAMAGE SEEN LOT OF THIS CANT USE STOCK BEARING NO NO OR YOUR LIFT IS TO HIGH FOR THE MOTOR ORAPLACATION HOPE THIS HELPS

Posted on Aug 13, 2009

  • 99 Answers

SOURCE: AT IDLE MY 2005 HARLEY FATBOY HAS A INTERMITTENT

better check for proper fuel flow weather their is no water penetrating in the fuel while in idle it can give problem 2nd thing is better check weather the spark plug are ok or not even sometime it can also cause problem so if required change the spark plugs or it is better you check in to an authorized Harley Davidson service station

Posted on Jun 29, 2010

jagjeffery
  • 318 Answers

SOURCE: valve noise after installing a big bore kit in my

Did you adjust the push rods?

Posted on May 08, 2011

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Engine knock hard over 2500 rpm


Does the oil light come on or the knock occur during the engine warm up after a cold start?
There could be a couple of problems causing the issue. You could have an oil pressure pump or pump pressure regulator sticking. I would have a mechanical oil pressure gauge installed and verify oil pressure at idle and 2500 rpms to make sure oil pressure is in normal ranges.
You could also have excessive piston rod bearing, crankshaft bearing or cam shaft bearing wear that will cause oil pressure to drop too low to prevent the rod knock your hearing at 2500 rpm.
You said a knock and not a ticking noise,so I don't believe a lifter is the issue at 2500 rpm.
Start with the oil pressure check and go from there.
Let me know.
Regards,

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Knocking sound during acceleration


I WOULD CHECK TIMNG AND MAKE SHERE YOUR GETING OIL TO UPPER END WHEN THEY DID UPGRADE DID THEY UPGRADE CAM BEARING TO IF NOT YOU COULD HAVE DONE MOTOR DAMAGE SEEN LOT OF THIS CANT USE STOCK BEARING NO NO OR YOUR LIFT IS TO HIGH FOR THE MOTOR ORAPLACATION HOPE THIS HELPS

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Large knock at start up.


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New pips


No.Although, it is a common practice to de-tune bikes at the factory so that they meet emissions requirements. All new injected HD's can expect a 4-6% increase in horsepower and 2-3% increase in torque just by dyno tuning the bike straight off the showroom floor. If you're riding a Low with a carb, then you do not need to have it re-jetted for slip-on's. If you're changing the exhaust from where it bolts to the engine, then yes you should. Dyno tuning is not as useful on carbureted bikes compared to injected ones, in fact I could tune a carbureted Low just as easily with an Exhaust Gas Analyzer as a dyno and save you $300. You're probably not that interested in minor differences in horsepower if you're doing slip-ons rather than a whole Screaming Eagle Stage 2 kit. Bolt 'em on and ride...

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