Turn Signal Problem

I'm new to this forum so please forgive me if this question has already been asked. I have a 2006 Road Star Midnight Silverado and a 2000 MM Royal Star Venture. I purchased a 1982 Maxim 750 for my son who has never ridden before. The 750 runs fine and everything seems to work except; the turn signals will come on at idle but will not flash. If you rev the engine a little they will start flashing. Let it idle and the turn signals stop flashing and just stay on again. One thing that may or may not have anything to do with it is that it had 1156 turn signal bulbs and the previous owner put new turn signals on it but they are 1157 bulbs. Only two of the three wires are being used. The 1156 bulbs that came out were marked 12V27W and the 1157 bulbs are marked 12V23W/8W. The previous owner said he replaced the flasher but the motorcycle still did the same thing. He said the battery was only 1 year old. Could a week battery cause something like this? Thanks for any help you can give me.
Harry :?:

 

the flashers are kind of picky about the bulb wattage, the right bulbs might solve the whole problem
in the meantime check the alternator brushes and water in the battery
the electrical systems on these doesn't have a lot to spare and needs to be in top condition

 

Thanks for the help. Thats a good starting place. I know even though the battery is only a year old the "Battery" indicator stays on. The previous owner said on this model taht the battery is suppose to have another lead that comes off it and if you plug the wire that is suppose to plug into it the "Battery" light will go out. So I assume that someone put the wromg battery in it. I also notice that when you rev it the headlight gets brighter. I starts just fine though.
Harry

 

this is actually something that was discussed in another thread a few months ago, and some people have experienced this issue.
My bike doesnt do it, but I am looking at getting LED lights to replace my bulbs just because of the low power consumption.
as for the dimming headlight, these alternators really dont come to use until 2k rpm. anything below that and you are on battery.

 

the battery may be right but the caps are wrong the wire he told you about goes to a battery cap that has a little lead probe on it that hangs down into the acid and sends a small voltage to the inst cluster
i think the probe goes to a white wire with a red stripe, you should find it near the battery
if the probe is still there you can try to put it in the second hole from - (i think) i just hooked it to + and it's good
this is what the voltage to the battery should look like, with the battery hooked up
never run the bike without the battery hooked up

 

Thanks for the help guys. I have been thinking of going to LED's. The turn signals the previous owner put on are probably to small to get LED's into but I can try and if not I can replace the hole turn signal. Thanks for the battery tip also I will check it out.
Harry