Anyone ever have a honda shadow? (VT500, 1984)

Hey guys - I trust most of your experience so I am asking here instead of a honda site.

We picked up a Honda Shadow for $100.



Threw the batt on some jumper cables and gave it a few turns.

Found the right choke mix and BAM popped right on. Within 30 seconds it was idling w/o choke.

Now, my question is this. It ran MINT, felt smooth, no dead spots in the throttle, went like hell down the street.

Then - after it was fully warmed, the fan kicked on to cool it. (water cooled twin, awesome!)

The lower half of the radiator was stone cold (by the fan) The upper half (near the head) was warm, but not hot. The motor was hot.

The kid we bought it from said he couldn't figure out why it was overheating.

My guess is - no/low coolant, or a bad thermostat. Sound right?

Is there anything honda or shadow specific I should start with?

If we don't fix this (or find a cheap way to do so) tomorrow, my moron friend is going to sell it because he's scrounging for cash. Yet he just paid $300 to adjust the valves on his LTD 700, when I said I could do it in an hour.

Any tips appreciated!

 

Air lock

Low Coolant

Bad fan switch

Impeller shot on water pump

Blown head gasket

Scale buildup in coolant circuit.

I'd run the engine from cold with the rad cap off and see if the coolant is circulating, or if the level is low. It might be a bad stat. I doubt it's anything major, they were pretty trouble free motorcycles.

 

Fan was working fine I know that, came on then it started running funny (ie hit high temp, couldn't cool and overheated)

How could the head gasket make it run great then when hot, not? Not saying you are wrong just really don't understand how that would do something like that.

If it's buildup I can probably run some sort of solvent right?

Thanks for the tips. Yes I have heard they were pretty trouble free.
Still a honda though. haha.

Love their bikes, mowers, ... that's about it! Forget their ATV's and cars lol.

 

First, try burping the system by running it with the cap off. Make sure the coolant overflow tank isn't empty. If it is, it may be cracked, and when the coolant expands into it, it might be getting dumped out onto the road. Then when the motor begins to cool off, it has no coolant to siphon back into the motor and it starts to run low. Click on this link to view water pump assembly:


http://www.bikebandit.com/houseofmotorc ... 0sch543390


Open it up and see if there are any blades left on the impeller. Antifreeze gets acidic after a few years and eats up stuff like that. Ford had a big problem with that on their 96-99 Taurus/Sable models. The impeller would get eaten up by the acidic coolant and plug up the heater. This was a problem in that all the engine coolant ran through the heater core, so when it plugged, the car overheated. They cured that by running another line parallel to the first, so then the heater core just plugged and left the engine unharmed. You usually found this out when you called for heat in the autumn morning and nothing happened. I used to flush mine every year.

If the impeller is there, try bumping the starter with the cover off and see if it turns with the motor. If it does, I'd then pull the thermostat and drop in in a pot of boiling water to see if it opens. If it does, I'd check the rad to see if it's plugged.

 

I've torn one of those down to bare frame and restored it. There's not much to the cooling system, you've gotten good advice to start looking for issues already, so i'll just wish you luck in sorting it out

Oh and tell your friend not to be an idiot and spruce it up some, make it safe and resell it for 1500% profit

Only thing i can add, if you take the coolant pipes off the head when cleaning it out, replace the o-rings and save yourself a ton of leaking grief