501 dont start when hot!!!

_alex_ · Feb 10, 2005

hello,

well after all that idle troubles,now the bike after hot it wont start

,it starts pretty well when cold.
i must go down climbing to get it started.
the valves is checked,and so all the rest...electrical?mechanical?

pls any advice...

alex

Taffy · Feb 11, 2005

the bikes need to run lean/leanish for them to restart succesfully. a 'hotstart' button on other machines simply adds air in to the stream to lean it off.

have you got a small pilot jet in it yet-what size?

regards

Taffy

fitz · Apr 10, 2005

Mine won't start hot either

I have a 98 FC501. starts 1st or 2nd kick when cold. Valves were just checked recently and should be pretty good. But after 20 minutes of riding, the bike won't start unless it's cooled down for literally 2 hours. Not good when riding in the sticks in the middle of no where.

How do you make it more "lean"? Which screw and which direction on the carb does it go?

Fitz

oldberger · Apr 10, 2005

Re: Mine won't start hot either

fitz said:
I have a 98 FC501. starts 1st or 2nd kick when cold. Valves were just checked recently and should be pretty good. But after 20 minutes of riding, the bike won't start unless it's cooled down for literally 2 hours. Not good when riding in the sticks in the middle of no where.

How do you make it more "lean"? Which screw and which direction on the carb does it go?

Fitz

2 screws on clutch cover side of carb, big one with visible spring sets the idle speed (will also affect hot starting) smaller one is the mixture screw. mixture screw should be somewhere between 2-2 1/2 turns out from closed (screw in clockwise until it stops then c clockwise 2 1/2 turns to start). mixture screw clockwise from here to lean mixture c clockwise to richen.

Also have a look at throttle needle for wear against needle jet. Change if worn or try lowering needle by raising the clip one notch.

There is a hard start guide in the download section which goes into more detail if all seems OK to that it is time to strip, clean and replace worn carb parts.

If all this fails PM Taffy the fuel expert

oldberger :roll:

coronaberg · Apr 10, 2005

no start

Sounds like you are not sure of your valves I would check them again!

berger · Apr 10, 2005

Most of the time I found you have not got the right starting routine down. You can try mine, it seems to work well on most Bergs.
1) pull in the manual decompressor
2) open the throttle (skip this if you have a FCR)
3) kick the bike threw 5 times ( clears out the old and perculated fuel charge as well as drys the plug)
4) bring it up to TDC
5) release the manual decompressor
6) give it a FULL strong smooth kick (make sure the kick lever is all the way to the top, dont cheat it)
7) If it does not start after the second kick, repeat the entire process

FC501EAST · Apr 10, 2005

Hi, _alex_ ..........
My '98 fc starts 2-3 kicks cold, 2-3 kicks hot, no problems. OEM Dellorto
PHM40ZS carb is set up as follows :
Needle : K51, second clip up.
needlejet : 270DR
Main jet : 172
Pilot jet : 35
Start jet : 45
Float needlejet : 300
Mixture (small) screw : 1 3/4 to 2 1/4 turns out.
Idle (Large Head) Screw : 5 to 5 1/2 turns out, gives idle at approx.
1650-1675 rpm.
I tried dropping pilot jet to 33, but made it harder to start cold and hot.

Start routine cold is turn on fuel, flip up choke, hands off throttle,
bring motor to TDC, kick through quickly and smoothly, FULL stroke.
Hot start is same, except leave choke off. Mine starts this way hot even
after being dropped :roll: !!
FWIW, I am at sea level here in Maine, only about a mile from the coast.
If you are at altitude, your carb settings will probably be a bit different.

Taffy · Apr 11, 2005

as coronaberg says, check those tappets again. also retrace anything you've done and check it through.

the web site has a 'hard start' procedure you can download.

how long since you changed the spark plug? try snipping off about 1/4" of the HT lead at each end and starting all over again using mastik this time to keep water and corrosion out.

check the decomp cables.

when it is running try to get it really warm and THEN adjust the air screw.

just ideas.

Taffy

fitz · Apr 12, 2005

Still won't start when hot

Thanks for all the ideas guys. I've adjusted the valves, adjusted the air and idle screws as per all the suggestions. The spark plug is clean. One mechanic suggested the magneto is getting hot and a bike won't start when the magneto is too hot.

Anyone have any comments on magneto's???

husabutt · Apr 12, 2005

If the stator (magneto) was going out it would more than likely give you trouble hot and cold.

Has it always done this or is this something new?

Do you use the choke to start it cold?

fitz · Apr 12, 2005

Hard to start hot

yes - I use the choke when cold. ususally starts in 5 kicks or so.

It starts ok as long as it's been running under 10 minutes. After that, it won't start until completely cooled down.

husabutt · Apr 12, 2005

Has it always done this? Alex I mean Fitz?

fitz · Apr 12, 2005

Hard to start

No - just in the past 30 hours of riding. Maybe even 20 hours of riding.

husabutt · Apr 12, 2005

If you have more than 150 hours on the bike I would get a complete carb rebuild kit as the needle and seat may be worn causing a too rich condition which will give you hot start problems.

Next have the coil and stator tested.

Make sure the valves are adjusted as stated previously.

When you get the carb apart be sure to get a magnifying glass and note all the jet sizes. Please post them.

Remember when kicking absolutely do not touch the throttle. Safety wire your right hand behind your back if you can't help yourself from twisting the throttle when kicking

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501 dont start when hot!!!

_alex_

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