Question about Harley Davidson XL 883C Sportster Custom Motorcycles

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I have an 86 sporster 883 that someone did the 1200 upgrade on years ago. Ive been having a problem with front cylinder fouling out the plug. ive cleaned and rejetted carb and still having same issue. how can i be sure im having a valve,valve guide or seat problem?

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  • Harley Davidson Master
  • 41,660 Answers

Hi Anonymous, I would definately do a leak down test, it will let you know if you have a ring or piston problem, air noise coming out of the crankcase breather, valve seat problem, air noise coming out of the intake or exhaust ports. What it will not diagnoise is a failed valve seal usually from improper installation or rotating engine before lifters bleed down. When a valve seal comes off the guide it turns from an umbrella into a pump. You should have noticed slight smoking out of the front cylinder exhaust pipe. Good luck

Posted on Apr 20, 2015


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Posted on Jan 02, 2017

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SOURCE: crf 250 not running correctly

Dear Wivs 1 hi I am vortash I am thinking this just might be your battery or your magneto , the bike is firing but has not got enough power to sustain it . Most bikes run off the mag once they have started so it should also run off the battery for a while , if the mag was down provided the battery was charged .So sounds like the magneto hasn't charged it , most modern mags have a detachable rectifier or is attached to a rectifier somewhere on the bike . Check the output if you have a multimeter ,if you have a 6volt system it should be producing approx 8-9volts DC , a 12 volt system should produce between 13.5 14.5 dc voltage . I am sure this bike was produced with both depending what market ie USA . Europe , etc
hopefully this will show you if you have a problem there .. However another symptom similar to what you have described is due to a cracked Cylinder sleeve , as it attains an explosives compresion the power is lost from the cylinder hence the bike stops .. you can test this simply by holding a sharp pin on the cylinder face roughly half way down and tracing around the cylinder if the pin finds a crack it will stop abruptly ... indicating it's posistion .
I have disscounted the obvious ie: fuel as you say that you have thouroghuly checked out the fuel system and providing this bike has not been modified in some way I think you have covered most of the area I would . hope this is of help Regards Vortash

Posted on May 14, 2009

  • 4565 Answers

SOURCE: kelhin 40mm cv carburettor harley 1200 xls

No sweat. Screw the idle mixture screw in until it "bottoms out". Do not tighten or you will damage the screw. Back the idle mixture screw out about three turns. Install carburator and check for proper operation.
When you get the bike running, allow it to warm up and then adjust the mixture for highest smoothest idle. Set idle speed to about 1000 rpm with the throttle stop screw.

Posted on Oct 06, 2009

Testimonial: "cracking "

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SOURCE: wat size single carb will power a 86 xr 600 rfvc engine ,

Hi Mate, The XR twin carbs were made '85 - '87. You can not fit a single carb to a twin port inlet manifold. If you were considdering swopping to a single carb cylinder head on the motor, that should fit the motor... BUT... the bike frames are different as to the position of the rear shock which will be smack bang in the way should you try to fit a single carb on a twin carb frame. If you got head problems and find it hard to get a replacement head, try a XR or XL 500 /600 or a GB500 /600 twin carb head.

Posted on Feb 15, 2010

  • 496 Answers

SOURCE: i have a 2004 vstar 1100 classic that backfires on

what you need to is pull a plug and see what it looks like this will tell what you need to do to your jetting. yes this could be a lean backfire it could also be fat. if your plugs are looking white your lean if they are back you fat. you need to get the bike fat before you lean it out. the first set in jetting is to get your bike to pull hard under full accl. once you have that then you can work out your idle. don't forget about your air/fuel screw. the air/fuel IS a part of everything from idle to full wide open. do you have pipes and a air filter? the best people to call is factory pro. they make jet kits and i have learned a lot from those kats.they know there poop and can get you set up right. remember to set your rear cyl just a little fatter then the front it will help with cooling. If you need more help please feel free to call me at the shop C.C. Motorsports (361) 885-7787
Good luck

Posted on Apr 29, 2010

  • 1 Answer

SOURCE: valve timing marks

hey,i have an xlh 883 89 model and i removed the camshaft cover out and one of the camshafts fell off cause the cover was stuck and had to make big pressure on it. i m trying to match the timing marks! is there a mark on the crankshaft sprocket? cause i m seeing a small dot that doesn t match to the other marks. i made it TDC from the inspection hole too, but the marks that have on the book aren t like the marks that i have on the cams how is exactly the camshafts timing? thanks

Posted on Jun 01, 2010

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3 Answers

Only running on rear cylinder

You are Not getting spark to ur front cylinder. Swap your spark plug, if not then replace your front plug wire. if this is still not the problem ad you are sure the coil is good then look into the wire that gives the coil signal to fire

Apr 22, 2014 | 1985 Honda VT 500 C Shadow

1 Answer

Weak firing on 883 sporster

Hi Anonymous, and the usual suspects are:
1. Plugs in bad condition or partially fouled.
2. Spark plug cables in bad condition or leaking.
3. Spark plug gap to close or to wide.
4. Faulty ignition coil, module and or sensor.
5. Battery nearly discarged.
6. Damaged wire or loose connections at battery terminals especially the ground cable at BOTH ends, ignition coil, or plug between ignition sensor and module.
7. Intermittent short circuit due to damaged wire insulation.
8. If your bike has a CKP sensor you must leave both plugs in
head and check for spark with a 3rd plug. Good luck.

Mar 12, 2013 | 1993 Harley Davidson XLH Sportster 883

1 Answer

I got a 1991 hd xlh883 sporster i had the timming repair and set and the carb set and still have no power in 5th gear only what do i need to look for?

If your engine has good compression and the carb and ignition timing is set correctly, you should be alright. The question did the bike have power before you had anything done to it? The 883's of late do not have the power the 883's of years ago had. The EPA is to blame for that. You may want to check the size of your front and rear belt pulleys. Someone may have changed them and put "international gearing" on the bike to keep the revs down at highway speeds. This will make the bike feel extremely sluggish in 5th gear.

Good Luck

Jun 04, 2011 | Harley Davidson XL Sportster 883...

1 Answer

Just purchased a 2001 sportster 883. Where is the steering lock located?

Seems to me that the steering lock is nothing more than just a loop on the frame and the front end that you put a pad lock into.

Oct 27, 2010 | 2004 Harley Davidson XL 1200 R Sporster...

1 Answer

Can someone tell me what the function of a bank angle sensor is and if it is making a rattling noise is it bad.

normally it warns you things are about to start scraping the deck,the switch could be the mercury type and that wront rattle,check for loose,broken brackets,etc as my 02 883 sporster used to vibrate a bit at certain revs

Jul 05, 2010 | 2002 Harley Davidson XL 1200 C Sportster...

2 Answers

I had a 1989, 883 engine rejugged to a 1200 three years

It depends on the kit you used to increase the engine size. You cannot simply bore the jugs and put stock 1200 cc pistons in them and then use your original 883 heads. Now, the question is who made the kit and was it designed to be used with unaltered 883 heads.

The problem arises for the smaller combustion chamber of the 883 head compared to the 1200 head. The 1200 head has a much larger combustion chamber resulting in a stock compression ratio of about 9.4 to 1 or thereabouts. If you use stock 1200 piston with an 883 head, your compression ratio will be approximately 12 to l so I've been told. I've never done that. Now, every time I've ever converted an 883 to 1200 and used the original heads, I've always used Weisco pistons designed for that specific application. So, the point is that you may have too much static compression on the engine.

There is another problem that could be causing this as well, vibration. Your older Sporty does not have the rubber mounted engine, therefore your battery is subjected to a lot more vibration. Also, since you've changed the pistons in your engine, your rotating assembly may not be balanced as well as it should be increasing the vibration.

Now, I usually tell people that the average battery life is about two years due to the vibration problem and heat. I have lots of friends that buy a new battery every two years just so they don't get left stranded.

Whenever buying a new battery, always get the highest cold cranking amps (CCA) that you can find and keep a battery tender on it all the time. This will increase your battery life as much as possible.

Good Luck

Jun 30, 2010 | 1993 Harley Davidson XLH Sportster 883

1 Answer

Misfiring until warmed up

One thing I noticed right away is you say full choke for 6 miles, WOW, that might be your cause, one of the spark plugs is gas-fouled. Change out the plugs, let the bike warm up some before you drive it so you don't have to use the choke/enrichener knob as much as you do. Let me know how that works out. BTW, I warm up my carburated HD until no choke is needed before I ride away, it can and does take some time.

May 27, 2010 | 2003 Harley Davidson XLH Sportster 883...

1 Answer

2005 sporster 1200 custom running like **** missing cuts off after warming , then will start up and run 5 minutes later?

Sounds like you're fouling your plugs with the enricher. If you leave your enricher on the entire time during the warmup, you may be fouling your plugs. The enricher is very rich so I usually leave the enricher on just long enough to get the engine to where I can keep it running with the throttle grip. Go light with the enricher.

Apr 22, 2010 | 2000 Harley Davidson XL 1200 C Sportster...

3 Answers

My 95 harley sporster has no spark

if you origionaly started running on one cylinder that's promising sounds like it your timing also check your magnito.... lisa

Dec 28, 2008 | 1993 Harley Davidson XLH Sportster 883

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