Bike Starts Up Good, Not Always Though

My bike starts up good every time, except sometimes.

Not sure if this is only, but from what I can remember, once I drove at 60mph for an hour. Parked the bike and a half hour later it goes, na, na, na, na, na, na, na.
Friend said, what's that about? Na, na, na, na, na, na, na, na, na, na.
From what I remember, when it doesn't start, you hit the starter with throttle off, and when its turning over, I roll on the throttle and about half way open it starts.
When it fires up, it is very low rpm and when you give it full, then builds up quick.

Why does the bike start very good, but sometimes it doesn't start right up?

Thank you,
Chris.

 

Time to pull the rack for a good cleansing, set fuel levels, bench sync', running sync' & then either color tune, or plug chops, to get your mixtures right.

 

If it needs all this, why does it start right up almost every time?

Chris.

 

Sounds like the fuel is getting hot and expanding in the float bowls. Could be flooding slightly and that's why the long crank and you have to open the throttle to get it to start.

MY 2Cnts
MN

 

I just got back from a restaurant. I saw a friend with a motorcycle and he told me the same thing.

He had me feel the carbs when I first got there. They where cold. When we came back, they where warm.

He explained that when driving, the fuel going through the carbs make it cold. After sitting, the heat of the motor heats up the full carbs and the fuel expands and floods.

I will open the throttle when this happens to let in more air to see if this is the problem.

Thank you,
Chris.

 

How many miles on the bike?

How many have you put on it?

When were the VALVE CLEARANCES last checked?

When were the carbs last serviced?

You asked for advice. The advice you were given is solid, if a bit incomplete. If you don't want to believe it, don't.

Valve clearances need to be checked every 5000 miles, after the initial check at 3000. Carbs need to be re-sync'ed after any valve shims are changed. Carbs need to be cleaned, adjusted and sync'ed every 10K miles (after a couple of valve adjustments.)

How much of this critical maintenance has been ignored on your bike?

 

How many miles on the bike? *7,2000

How many have you put on it? *2,000

When were the VALVE CLEARANCES last checked? *Don't know, got the bike 2,000 miles a go.

When were the carbs last serviced? Don't know.

You asked for advice. The advice you were given is solid, if a bit incomplete. If you don't want to believe it, don't.

Carbs need to be cleaned, adjusted and sync'ed every 10K miles
*OK, this means I'm not ready for a carb service for another 3,000 miles.

How much of this critical maintenance has been ignored on your bike?
*None, as far as I can tell. Just changed the original tires so they may be one thing.

 

You are thinking about miles for service needed.

You really should be thinking about the wrath of time and how that effects certain parts of that bike.

 

I thought valves get out from use, not from sitting.

MN-Maxims, I'm jealous you have so many square XJ's. That's one reason I liked the XJ's so much. I didn't really think about it when I bought mine, not until I got home did I realize mine was round.
Chris.

 

The valves don't get tighter from sitting. It's the PO that probably never took it back in to get the valves set. You should pop the valve cover off and double check to see where you are at so you know they are not tight. Hate to hear you burned a valve because you thought the last guy had done what he was supposed to. As a general rule don't assume any thing on these bikes. Most of the guys who bought them back in the day would not spend the money to get the maintenance done at the shop. Also there was not a forum like this for support to help guys that could have done the work themselves.