Ironhead 72 dies when clutch let out all the way

[psycho]

friend bought 72 sporty didn't run ,I went through hole bike.everything looks ok. idles and revs up on lift put on ground once clutch is out all the way bogs down dies,pull in clutch hit start button fires right up.

[bustert]

if it sat up that long, you may have fuel issues. an engine requires very little power to rev on its own as it only over-comes internal resistance but once on the ground, more power is needed to over-come the load.

[rivethog]

2 questions.
#1- Does the bike roll easily in neutral with the engine not running?
#2- Are you absolutely positive that you're taking off in 1st gear?

[psycho]

will get going if clutch not let out all the way,carb was hot tanked gone through, new gas.pushrod adj.checked,points adj both lobes 18-20,timed .gone through everything triple times one of those gremlins.

[psycho]

spins easy on lift going through all gears ,thought might be tranny no play output sprocket

[bustert]

a bath is a good idea and is better than snake oil fixes. there is one other issue that a gunk bath sometimes does not fix. the carb has air passages as well and if plugged, will cause mix problems. on a carb that is suspect for blockage, i will use a acid base coil cleaner to dissolve any bloom, a gunk bath and hot like you did is a good idea, followed by an electro-clean bath or a dawn detergent boiling water bath and then blown out with air. sadly, some carbs become trash!!!

[psycho]

I agree 100% ultrasonic with dawn and acid bath done and blown out,thinking might be carb is shit

[piniongear]

Originally Posted by psycho

friend bought 72 sporty didn't run ,I went through hole bike.everything looks ok. idles and revs up on lift put on ground once clutch is out all the way bogs down dies,pull in clutch hit start button fires right up.

It really sounds to me like it may be an issue related to learning how an ironhead runs.

First of all, if the bike has sat a long time without being started (like 6 mos to a year or more) then the first thing you want to do is drain the primary and transmission oil.
See how much comes out.
Refill with 24oz of 60wt oil, the same as the engine uses. This is a 1972 so it has the transfer valve.

Then look in the oil tank and make sure it is up to the full level.
Next, start the bike and let the engine warm up for 3 or 4 minutes.
Push it down the driveway with the engine running in neutral and jump aboard.

While the bike is still rolling forward, blip the throttle and put it in first gear.
The bike will most likely jump forward so just give it some throttle and ride it around the block.

When you return, the clutch should work much better.
Let us know the results.
pg

[psycho]

nice try been building, racing ironheads since late 60's,when I said been through everything I mean everything clutch works fine all fluids replaced before startup.this is a gremlin !!!!!!!!!!!!!!I came on this forum as a last resort,it has three other top notch ironhead gurus stumped.

[Wooley]

Originally Posted by psycho

friend bought 72 sporty didn't run ,I went through hole bike.everything looks ok. idles and revs up on lift put on ground once clutch is out all the way bogs down dies,pull in clutch hit start button fires right up.

sounds like the low speed mixture needle or passages aren't clear. No load it runs fine but add partial to full load and it can't get enough fuel and stalls.