left engine rpms falling back

[xXxBurnStuffxXx]

my sportster 1800 (1998) is having a problem when i accelerate. when i take it out like every week i keep having the same problem. the first time i run at full throttle after a weeks rest it run fine for about a minute or two. the the left engine drops down to about 4-5000 rpms... then 2 seconds later trys to pick back up to 7-8000 rpms. but once again gets knocked back down to 4-5000. eventually it wont even try to get back up there and will stay at that speed. what are some problems that could be occuring and try to run me through the process to fix this. pleaseee help!!

 

[JoeZ]

Spark or Fuel.

I would think spark in this case. It is kinda hard to test with both engines running, so you'll have to just start the port engine and test for spark. Make sure it is strong and that the plugs look good. Also check compression since you'll have the plugs out anyway.

Let us know from there and we'll start to narrow it down.

 

[xXxBurnStuffxXx]

im not too sure how to check for compression... isnt there a certain tool i need?

 

[JoeZ]

Yes...you can get it at any automotive store. The Super Walmart on 41 should have one as well (I went to Venice High)

 

[xXxBurnStuffxXx]

well.. i cant really test the compression now... because the left engine wont turn over. BUT when i press the button i hear a click. i dont think this is low battery because it was just charged and the right one turns on. also about a month ago i had a new electric starter put in...