J&P Community

   I have had this issue since last year...I put new top end on,new carb,lapped valves,new gaskets.When I throttle up I beleive I can hear a loss of compression somewhere.At idle bike sonds awesome,puttin round sounds good,when I open her up hit good for few seconds then falls on front wheel....I dont see any cracks in heads or cylinders or anything like that.Can  it be from cases somehwere?Even sound through pipe is different from back,just dont have the deep sound like the back one does unless idling.By the way it is an 81 ironhead....I ask of any suggestion as I really love this bike but am gettin ready to ditch it and go back to my truck......

   Put baby powder on cylinders and nothing blew,could maybe be a cam issue???The oil pump went out is what started this whole top end ordeal so maybe be a lobe gone?????

 have you run a compression test on both cylinders? that's where to start. if you can figure out which one has the problem, then you can tear that one down to find the problem

Framer,

The Ironheads have solid lifters. You may just have a tight one on the front cyl. I'd run em all again. After a build, you should adjust them all again after the initial run-in.

 just ran compression test.150 both cylinders.how can I check cams without pullin cam cover off???

  Pulled the lifter out of the cylinders I coud get,both back and exhaust on front.The one on front has a ring wore in the roller on it but havent looked at cam.feels good just the grove worries me..The exhaust valves were clos to same adjustment on the screws but the front intake was out way more than the rear intake.......

 Put it back together and still same thing,I even left lifters just a little on the loose side.I swear I hear a leak when I throttle up but cant find where.With 150 psi on boh cylinders exact I am stumped..It is chargin good but battery is kind of crappy ,would that cause an issue???

Then you might want to do a 'leak-down' test......

You can also measure cam lift at each exposed pushrod, while slowly rotating the motor.. 

 shoot air in the cylinders?I was going to do that tomorrow.Can anyone tell me what jets I should be running in an S&S E?

 I have 64 and 295 in my '77 (.020 over, couple of hundred feet above sea level, high humidity)

When you had the lifters out, did you run a mike on the lifter and the blocks to ensure they were in spec (I had to replace my lifters last winter - 3 were definately out-of-spec and 1 was border line - funny thing, the blocks made out of alunimum were fine the lifters made out of steel had to be replaced)?

Another question, when you built the top end, did you replace any of the guides?  if so, with steel or . . .? (thinking of a guide moving - stuck to the lifter when it heats up)

hope this helps

 no didnt mic the lifters,will do that tomorrow,checked guides and springs last time I had heads off and tehy seemed fine.Just something simple I think and cant figure it out.When I crack the throttle it hits good then loses all oomph and is just kinda there....

   Should I be able to hear air when I spin the motor over by hand?Sounds like a hissing or gurgling down by base of cylinders somewhere cant tell where it is coming from....By the way the plugs are out also.....

Framer,

  Did you have the cams out of it? Have you checked for a vacuum leak at carb manifold? What do the spark plugs look like after a hard run and it messes up. Take a plug wrench with you, and shut it down right when it happenes, coast to the side of the road, and pull the plugs.

 plugs look carboned up but starting to turn back tan after I reset timing,leak was a pushrod cover.Could that affect it any cause that started when the power loss did.also should I be static timing off the line or the little dot before the line??

  No Framer, a push rod cover leak won't cause a power loss. I think on your bike, you time it on the dot, but check your manual. I still think you may have a tight valve adjustment. Book says barely discernable play, cold. When an Ironhead heats up, the valve adjustment tightens. If you're too tight to begin with, when it gets hot, they'll leak. My philosophy is: If you can't hear them when the engine's cold, they're too tight.................