So just tossing this out there to see if anyone has had this happen or know what it could be.

Hard starting unless I dump gas down the carb.
I’ve got 70lbs in both cylinders.,
check intake seals, tight as a drum!
spark all day long, strong to boot.
used two rebuilt carbs but get the same results, no start.
totally stumped!

 

You have to pressure test the intake seals and use soapy water, tight means nothing. My guess is a vacuum leak.

 

Yeah did that, leak test bubble free.
Tried two carbs, totally rebuilt and each didn’t change anything.
By the way it just came on out of no where.

 

1 how loose was the Venturi does it fall out when the nozzle is removed

2 how tight is the throttle shaft in the top and bottom bushings you want zero

3 throttle blade wear on the carb body when it’s closing will eliminiate the sip needed for starting

4 float and its location is in play as is carb angle to standing height of the bike

then you have ignition - coil is always suspect but you say it’s working - condenser is a big issue and yes it will spark with a bad condenser

failing battery is also in play have had them work till the plugs are in and it has compression as that takes greater effort from the system to work

pictures of the carb stuff mentioned above could see something you dont

 

A fat chalk stick to diagram the issue in the driveway may help

 

When you did the bubble test, you held 14 PSI for a couple of minutes and kept checking?

Coil is always suspect, whose coil is it?

You say this just started, what was happening before and what were you doing when it started?

Air leaks in the carb will cause havoc, what was on it and what do you replace it with?

 

So to answer John question:

1. the Venturi tube isn’t loose, matter of fact it always easy to drop in but hard getting out. But no on being loose.

2. Bushing for throttle shaft replaced a year ago and still tight.

3. The disk for the throttle is square and adjusted tight, no light when closed.
4. the float is adjusted to 1/4” deep off of bowl edge and a bit to the left, as per manual.

Ill recheck the intake seals again for the 5th time, but more than sure its bubble tight.

after that I’ll try a spare coil I’ve got to see if it makes any different.

Bike was running good about a month ago and than it wouldn’t start.
checked compression in cylinders and found no psi in front cylinder.
found valves out of adjustment and readjusted
and now both cylinders have 70 psi.

It would start one day, and than next it wouldn’t????
Spark plugs are black not burning clean appears very rich.
Unless the carb is set to rich I can’t see that being the issue. The carb idle adjustment screw is only set at 2 1/2 turns off the bottom .

So that where I’m now.

 

If using V Twin coil or something like that, time to move on. Jeff's coils look better, work 1000x better and wire like stock, not backwards like V Twin

Jeff Goorman.
Bulldog Brothers Garage
303-435-3212

bulldogbrothersgarage@gmail.com

 

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[QUOTE=Dan89FLSTC;21495316]When you did the compression test, did you have the throttle butterfly/slide wide open?

70 PSI is too low...[/QUOTE
First adjusted valves, and than did compression test with throttle wide open.