Question about Harley Davidson XL 1200 R Sporster Roadster Motorcycles

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I have a 97 sportster that pops at idle and pretty much runs on one cyl. for the most part (front cyl.) It has been modified w/je pistons edlebrock heads, compu-fire ignition,thunderheader, mikuni hsr42,and a mild sceamin eagle cam, and a hypercharger. I have checked the pushrod adj. plugs,wires,coil, and replaced the ignition module. Any ideas? Or educated guesses? I do appreciate your time and your help

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  • BUMBL3B33 May 11, 2010

    Have you had a dry compression test? also try a wet one..
    Id have a look at that injector too.


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I'd take a closer look at your coil seen many occasions where either the spade connector is not makeing good contact or the sparkplug wire when you you remove it from coil is it leaving any thing behind?sometimes the metal connector stays in the coil if not do a resistance test on plug wires and ck wires from ignition module to coil i dont think youll find anything with a compresion check but im sure id like to see bumbl3b33 look at an injector on a caurborated bike!

Posted on Dec 18, 2009

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Hav u done a compression chec on that combust chamber other than that its electrical or fuel related-secure a clymer manual for HD-see them in library alot sec629

Posted on Sep 09, 2009

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97 harley davidson sportster 1200 spits, sputters, and stalls

Hi Anonymous, popping, coughing, spitting, or backfiring through the carburator or induction module can be caused by air getting sucked in combustion chamber do bad intake seals leaking. Leaking exhaust gaskets can also be suspect. Remove air cleaner and backing plate, while engine is idling spray WD-40 or Brake Kleen around intake manifold to head area, if RPM's increase you have an intake leak and seals need to be replaced, also spark plugs will be burning whiter than normal. Good luck

Feb 03, 2013 | 2002 Harley Davidson XL 1200 C Sportster...

1 Answer

I have a 30ltr TDI quattro that smokes when it idles for than a few minutes

This car doesn't have coils and wires, it's gasoil. The most likely reason is the piezo injectors are worn. The best way to test is with VCDS
After an overnight stationary period drive the vehicle with cold engine between 1200 - 1600 rpm till the complaint occurs. Constantly read the measured value block 13 and 14 for the smooth running control in the engine control unit. The values of one or several cylinders should noticeably move to positive.

modified injectors A8: with 3.0l, 4.2l TDI from: WAUZZZ4E*7N016685
Replace the injector with the highest deviation and all injectors produced between 1.3.2006 and 30.4.2006.
Example of production date: 060304 stands for 4.3.2006
vcds go to address 01 measured values below
013 Smooth running control1)Cyl. 1 Injection quantity variation[mg/stroke]2)Cyl. 2 Injection quantity variation[mg/stroke]3)Cyl. 3 Injection quantity variation[mg/stroke]4) VacantPermissible values at idle: +- 2,99 mg/strokeA If the permissible tolerance is exceededfirst check injector IQA-IVA adaption values
014 Smooth running control1)Cyl. 4 Injection quantity variation[mg/stroke]2)Cyl. 5 Injection quantity variation[mg/stroke]3)Cyl. 6 Injection quantity variation[mg/stroke]4) VacantPermissible values at idle: +- 2,99 mg/strokeA If the permissible tolerance is exceededfirst check injector IQA-IVA adaption values

Jun 28, 2012 | 2006 Audi A6 3.0

1 Answer

'97 rstd cold start, full choke,, cyl 3&4 do not fire. lots of popping/after-fire from right side till warmed up a bit. once warmed up runs/idles ok. good spark thru all. idle fuel circuit problem or...

low milage tells me most likley the carb is gummed up. You may need to remove and clean out or try some fuel injection cleaner. Use twice as strong as recommended. Your description points to not enough fuel when cold which is when it needs the most. If your handy I would remove the bowl and blow out all chambers and tubes with brake cleaner.

Jul 29, 2010 | 1997 Yamaha Royal Star XVZ 1300 A

1 Answer

Wondering if anyone knows where the adjuster for the carburetor is located on a 2001 1200 Sportster custom

Unless the carburetor has been modified, the only adjustment is the idle speed. The Idle Stop screw is located at the upper right side of the carb. You may have to remove the air cleaner cover to access the screw. Clockwise rotation increases the idle speed. Adjust the idle speed with the engine at full operating temperature.

Jul 15, 2010 | 2001 Harley Davidson XL 1200 C Sportster...

2 Answers


the knocking is probably the connecting rod that is between the piston and the crankshaft....the pop you heard was it breaking. this is major engine repair and needs to be looked at by profesionals.

May 05, 2009 | 1997 Buick Park Avenue

1 Answer

My 1989 vmax has poor compression on the rear 2 cylinders.

You can rule out poor piston rings by doing another compression test, this time with a teaspoon or two of oil in the cylinder. Oil will help seal a piston ring (raising compression temporarily), but will have no effect on valves. I would suggest burnt valves rather than bent. That might explain why only the back two cylinders, they run a little hotter. Under normal circumstances (stock exhaust, sane driving) not hot enough to make a difference but if your previous owner was a clown who knows?

Good luck Nik, those bikes are a lot of fun and pretty reliable when done right.

Jan 15, 2009 | 2002 Yamaha V-Max

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