gs550- hard starting when hot

[Guest]

maybe someone can help. have a 82 550m. bike runs great, starts fine when cold. when hot--- if I turn her off/ then on she'll start up. but if I turn her off, and wait a minute or 5. she cranks over but wont start. even thou a few steps and 2nd gear and she bumps to life fine. the battery is new and like I said she runs fine. she has a 4-1 exhaust, k&n 2-4 filters w/ a DJ stage 3 kit. anybody else have the same problem? some kind of vapor lock in the carbs (maybe starting her on "prime") thanks if anybody can help, tom

[tom203]

When it's hot and you crank it over, does it seem that crank is turning over (soundwise) same as a cold start? maybe your starter motor doesn't like getting warm

[BassCliff]

Hi,

Have you replaced the intake boot and intake boot O-rings?

Have a look here: New Members, CLICK HERE!!


Thank you for your indulgence,

BassCliff

[cyclocrossfool]

you replaced the intake boot and intake boot O-rings?



BassCliff

yeah, I sent the carbs out to be rebuilt (chef) and all the o rings in the carbs replaced. and then put the new larger o rings in (between the head and boots). the boots themselves look in good shape. a look at the plugs- im a little rich.- choc brown in color.i put a new vacuum tube on (the one that goes from the petcock to carb #2) ill see if that makes a difference. thanks all for the input, tom

[mike_of_bbg]

You probably need to clean up the electrical contacts everywhere. Check your volts at the coils. If it bump starts fine but struggles to fire on the starter, you're likely having an issue with voltage drop. The stress of running the starter is taking the system voltage down and your drop to the coils is making for very, very weak spark. I had this issue and used a coil relay mod. Try cleaning or replacing your plugs, too. Also check coil impedance primary and secondary, and make sure none of your plug boots have gone bad.

[cyclocrossfool]

I had this issue and used a coil relay mod.

something i can buy? or do? (help please) thanks again for the help, tom

[koolaid_kid]

It is something you build yourself using a Bosch-style relay. There are many, many ways to skin this rabbit. On my GPz I connected it to an second fuse block, and use it to power my coils, grip heaters, aftermarket horns, and a 12V adapter for items that use one. I also implemented it without cutting any factory wires.
Or you could implement a very simple one that just powers the coils. Dealer's choice.

[mike_of_bbg]

something i can buy? or do? (help please) thanks again for the help, tom

There's a page about it off of BassCliff's site:

http://members.dslextreme.com/users/bikecliff/images/coil_relay_mod.html

Basically the electricity that goes to your ignition system has to take a lot of hops along the way. The coils are the most sensitive to voltage drops. The point is largely moot if all of your electrical connections are clean and corrosion-free. However, some of the more suspect connections are difficult to get (and keep) clean, like the kill switch in the right hand control and internally to the ignition key switch itself. KK is correct that there are multiple ways to skin this cat. If you're getting a drop of 2-3V between battery and coils already, when your battery is under stress turning the starter motor it will be putting out lower voltage. So the idea is to set up a more direct path from battery to coils to take potential sources of voltage loss out of the path. The reduced voltage going to the coils may not be enough to get juicy spark, but is probably plenty to work a relay to switch a more direct line from the battery.

I could be totally wrong. The main clue to me is that you can bump start it just fine where the starter fails to get it cranking.

[koolaid_kid]

It is easily tested:
Remove the seat and tank.
Place the red probe of yuur voltmeter in the orange/white wire from one of the coils and the black on the negative terminal of the battery.
Turn the key on. Voltage should be around 12V
Keeping the probes in place, hit the starter button and check the voltage again. If it drops to 10V or less, you need the relay mod.

[cyclocrossfool]

ill do this tomorrow, thanks, t

[cyclocrossfool]

did the "mr steve" one. but instead of taking the power (+) from the kill switch. I went from the + battery to a fuse to a added on on/off switch(making sure its in the "off" pos. when not running). and yes it seems to be working. after shutting the bike off and waiting a few min. it starts right back up. thanks to everyone for the help. tom