Not a cold start problem

[Shadowform]

In fact its the complete opposite!
Morning guys, Let me start by saying that this is only my second bike and the first one is still in boxes in my garage, not to say that I know nothing about them just that my mech experience is primarily limited to cars although i am very quick to pick up a wrench and figure **** out! So here's the skinny, its an 85 500 shadow, runs very good since reworking carbs, and by reworking i mean; disassemble, clean out the lovely fuel jelly(its not that good on toast BTW), soak, blow out, re-soak, re-assemble. It now starts instantly with only minimal choke, and runs 100x better. Very responsive, no hesitation, very nice.
The problem comes 10 minutes later when I shut it off, it will not restart until its
cold again regardless of choke or throttle positions. Is this a valve issue? Are they expanding with the heat and then not seating once its warm (and I say warm because the gauge works and never gets past the first section of the cool side) thus not allowing compression?

Other notes: Exhaust is 1/2 missing no muffler or further
Standard airbox w/filter
No know mods

Thanks in advance
Steve

[John Hopkins]

The exhaust could be part of the problem as could overheating, Oil, oil filter clean, coolant circulating, fan working, feel the exhaust headers as soon as you start the engine are the both hot, check the plugs and make sure the air filter is clean..

I don't think I would be looking at the valves but if the bike has been standing a long time maybe engine sludge has blocked some of the oilways and needs some flushing oil run through it for a few minutes, at least if it comes out filthy it will tell you how much it needed doing..

John.

[tubes_rock]

If you don't shut it off and just ride it for an hour, does the performance drop off after the engine heats up, or will it run all day until you shut it off?

How do your spark plugs look? Are you running way too lean? Without the back-pressure of mufflers, stock 1980s Honda jetting will have you running in a dangerously lean zone. Be careful running it like that if you have stock jets.

--Justin

[Razorbackkid]

Inspect the coils.

[Scrapdog2grand]

check to see if you have spark when this happens. ^ may be ignition related.

["Captain D"]

Tune up???
When was that done last???
Check thecoilsfer cracks...
Sticky;what to check when my Bike won`t start???

[ernie12b]

this sounds like the vt500 hot start problem. this is common and is a combination of things. first the bike is over 25 years old. The coils are located over the front jug so they get hot and tend to get weak when old and hot, the starter motor gets hot on the back of the engine causing it to draw more current (starter rebuild helps alot) then the battery needs to be strong even a little low will leave you waiting for it to cool. I could bumpstart my bike hot all day long but no chance with the starter. after rebuild of the starter and new battery it would usually start fine. another problem is you need to ride quite a bit at highway speed to recharge the battery after starting. 3 or 4 short hops can drain it alot. yes it would crank quite a bit when hot but not start.

[Inferno]

Did you reset your floats?
You said you had knowledge of cars...

Remember vapor lock in the old days (say 70's or so)?
I know on a Solex carb, the heat from the engine could cause a low float to evaporate the fuel before it's able to fire (when hot starting) and a high float would boil over.

Smell the exhaust when it won't hot start. The degree of raw gas smell will help.

[Shadowform]

Thanks to all that have responded, I didn't want you to think i was ignoring you but with the holiday visitors and all, I haven't been able to really get away to check the items mentioned. I will say though that the battery thing sounds like the possible issue because i do only start it for short periods to warn it up and when I reconnect the charger/conditioner it is only at about 25-35%, this is after a few attempts to restart it, but its pretty low regardless. So thanks again and happy holidays to all. I will update on any progress after family leaves.

[95shadow1099]

Check the battery voltage while starter is crankin with a digital multimeter. It should be 12+ key off, AT LEAST 11.8 key on (not crankin) and HAS TO BE 10.5+ while crankin engine or it will not fire. My 750 has an un-known age battery in it, it apparently is weak. I done some checking the other day and found it's turning over at a seemingly "fast enough" rate not to be a dead battery, although it's only about 10.1/10.3V while engine is rotating..... You can literally crank it for 30 sec continuous and it will not fire. This is cold/hot, doesn't matter. It has good charging system, 14.1+ at all rpm''s while running.

Here's my point, it will start/fire IMMEDIATELY with ANY additional charger/jump box on the battery. I have a big "roll around" one, 12V 2Amp is sufficient to make her start. With additional "juice" connected, it's something like 11.4/11.6 at crankin.....enough to fire the plugs.

I haven't bought a new battery, it's winter, and I have other bikes to ride.

Said bike has failed to start on me 2 different times, both after riding 1-3 miles and shutting it off. Crank and crank and crank, cell phone call for my jump box and she's running again, in 1 second! The speed of engine rotation with/without extra juice is very minimum....almost un-noticeable, I'm guessing maybe 10-20rpms difference.

Hope this helps. My 750 needs/uses the 16A battery vs. the 14A, not sure about your 500.