• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

450s hesitation problems

  • Thread starter Thread starter fire_red
  • Start date Start date
F

fire_red

Guest
I just recently got my 1980 450s reserected from the dead. It was running great and all of a sudden when I reach 50 mph it just dies. I have good rpm range up thru 4th gear. After that it just dies, no power at all. I have just tried some crab cleaner but Iwould think that would give me hesitation thru all gears. Any help would be greatly appreciated.
 
Fuel flow problem.
Check;
petcock
Vent lines
Vent in fuel cap

Did you do a full cleaning of the carbs like here
 
Last edited:
fuel

fuel

That was a very informative article. I did do most of that stuff in order to get the bike running to begin with. I did not replace any of the o ring gaskets. I feel that I am getting enough fuel to the carbs. I think it might be to much fuel. My left plug was pretty black but the right one was perfect. I added some carb cleaner to the gas. If it was gas flow why wait until it reaches 4th gear? I would think it would hesitate thru all rpm range? Would a valve cause this?I am alittle baffled.
 
My bike did the same thing and it was the petcock. It wasn't flowing fuel properly so the float bowls would run out of gas. It doesn't happen right away. The vent lines in between the carbs can cause a problem at higher speeds when the air hits them. That's why they need to be tucked away between the air boxes. The fuel cap vent also doesn't happen right away cause the tank gradually builds up pressure and reduces or stops the fuel flow.
 
petcock

petcock

OK will have to check on the petcock. Where is the fuel cap vent located? Did not know there was such a thing I needed to worry about.It just seems weird because The bike never actually shutts the motor off, just has no power. I move from 4th gear to 3rd gear and the bike runs good. Its like when I get above a certain speed and roll thr trottle open it just chokes itself out of gas or air maybe it fluds itself with to much gas? Will check on the overflow hoses tonight to make sure there situated properly.Some very good places to start.
 
There is a vent inside the fuel cap. If the top of the tank is sealed there is no way that fuel will flow out the bottom.
 
If the petcock does not fix the problem it might be the ignitor. Typically causes the igniton to shut down at high rpm. Good luck.
 
Last edited:
Nessism said:
If the petcock does not fix the problem the problem it might be the ignitor. Typically causes the igniton to shut down at high rpm. Good luck.
Click to expand...

I will echo this!!! I am having the same issues and so far everything is leading towards the igniter. Get a good manual so you can get the specs for the igniter and coils. Also use a timing light and check the pick up plate. When I checked mine, you could actually see the ignition miss with the timing light.
 
problems

problems

What is the pick up plate? How do I check the pick up plate with the timeing light? So many things to check.
 
On the right side of the engine there is a round crankcase cover. Remove it. Under it is the crank trigger-pickups. Put the timing light on the #1 spark plug wire.
You should see some timing marks through a small sight hole. Shine the timing light in there. Give some throttle and you'll notice the timing mark "advance". It should be a nice steady smooth advance and not jumping around.
 
You must log in or register to reply here.
Back
Top