Hard start after sitting

Been awhile since I've been on but I've been doing more riding that wrenching! The question pertains to my dads 86 Radian. I know, its not a XJ but it shares the same carbs with one and I figure its close enough that you all should be able to help me out.

The issue arises after the bike has been sitting for several days. It just plain doesn't want to start, if you sit there and crank and crank it will gradually hit a lick, then a little more and eventually it will start and idle, but don't touch the gas till its warmed up or it will stall. I think it isn't getting fuel because a quick shot of ether and it hits right off. Also, if you start and ride it every day it starts fine.

Now before you give me the spiel, I'm no stranger to the platform. I've adjusted the valves, cleaned and rebuilt the carbs more times than I care to count, set the float levels and synced it over the past several years. This is the last little hurdle I need to get over and it will be a great bike.

So where do I start? I already pulled and disassembled the carbs to make sure they weren't dirty. Do the pilot mixture screws have anything to do with it? I appreciate any help or suggestions. Thanks.

 

The Radian is pretty much an XJ. Updated XJ550 engine in a XJ550 Maxim Frame. Other than the unique cosmetics and tank, it's a parts-bin bike (and a good one too).

The float bowls will dry out after a few days of sitting. Set the petcock to PRIme so the float bowls fill before starting.
The XJ series does have to warm up before you can ride. Mine needs about 3 minutes in warm weather, and a bit longe when it's below 50ºF (and I know how cold it's been in Ohio lately since I'm there now).

When you pulled the carbs, did you replace any of the rubber parts?
Did you clean the enrichment jets in the float bowls?

Pilot mixture screws should be set to 2 1/2 turns out as a baseline, and tuned from there (usually they will end up at 2 3/4 turns out).

 

If your bike won't start after sitting for a couple of days, there's an easy solution: ride it every day!

 

I had this problem, but on a different bike and for a different reason. Check your oil as well, make sure the fuel is not going past your carb into your crank case. The last thing you want to do is grenade the engine.

If the oil smells like gas, then it could be a stuck float with a mixture of a bad Petcock gasket. I had to replace my petcock gasket and clean my carb. Easy fix, but replacing the gaskets to the transfer case was a pain. Fuel will weaken the gaskets and bearings in your engine, causing all kinds of trouble. I doubt it's that... but you never know.

Hope your crank is clean. That's the last thing you want.

 

Like k-more said, set the peacock to prime for 15-20 seconds an see if that helps. I've had the same problem but usually it after a couple of weeks. 2 off 3 days seems fast unless something is leaking.

 

I've tried setting it to prime. Doesn't seem to make a difference.
I always let them warm up before riding, the issue arises on trying to get it to initially start so it CAN warm up!
By rubber parts what do you mean? When I rebuilt them they got new fuel mixture O-rings, float needles and bowl gaskets. I didn't actually break the rack apart to replace the fuel rail orings.
I did clean the enrichment circuit. Pulled them and cleaned them again yesterday. Didn't see anything suspicious but it did act like it wanted to fire in 20* weather yesterday. Never actually did though.

 

I was waiting for this answer, because that was my solution also! If it was mine it wouldn't be a problem. The old man is a fair weather rider!

 

I'll definitely check that just in case. I just rebuilt the petcock last year so I don't think its leaking.

 

Try jumping it with a car battery. Maybe your battery is losing power while sitting. I keep mine on a battery tender any time It's in the garage.

 

Will jumping the bike with a car battery harm it? Are you talking about trickle charging the bike battery from the car battery? Or start the car, plug them both to each-other and turn over the bike?

I heard very bad juujuu will arise if you do that. I could be incorrect, I am extremely electrically ignorant.

 

20 degee weather is a hard start for me with out using starter fluid, 30 degrees easy
could be the fuel or motor is just to cold.
I do not ride below 35 degrees do not like hitting ice from snow banks melting and refreezing

edit
oil should also be correct wt for the colder weather start

 

DO NOT start the car , just hook up the battery with jumper cables.
a battery tender on the bikes battery is what you need for cold weather starts and the proper weight oil for the cold weather.
but you should remove the battery for the winter and put it on a tender in the warmth of your house

 

Break the carb rack today, replace throttle shaft seals, and fuel rail 'rubbers'. Go to Church with them, cause in a month or so when the weather really turns nice you don't want to be fiddle fudging with running/ idle issues.

http://xjbikes.com/forums/threads/in-the-church-of-clean.14692/

 

A battery tender keeps the batery from discharging to the point that is becomes an ex-battery. It should not be hooked up when you start the motorcycle as it is only rated for 2 amps max (typical) and can be damaged by excessive current draw when starting.