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Discussion Starter #1
Well, I may of made a hasty decision when I purchased this bike. I didn't read up on the history of these hondas but it looked so clean and it had only 7.8k miles on it! It test drove nice and smooth and everything seemed ok. This is my first big bike purchase. I have just been doing vintage mopeds for the last 6 years...restoring them and getting them to go fast (fast is a relative term to mopeds, lol)

Allegedly, the bike was serviced in 2009 to "get the bike on the road again," as the service ticket stated. It mentioned carb cleaning and syncing. The mileage on the ticket was around 7100 I believe. Since then there is about 7800 miles.

First off, if the bike was shoved in a corner for so long, could it be possible the carbs would be gummed up pretty bad after that short little stint of sitting?

I just changed the oil, and put new plugs in the bike.

Here are the symptoms. After getting the bike nice and warmed up after a long ride, the idle would sit around 1k and slowly want to go down. Then the oil light will flicker as the rpms get really low and the bike will stall out. First, I didn't have the vacuum hose hooked up to the petcock, it was sealed off. It seamed fine with a full tank of gas, but the problem seamed to be when I burned off about one gallon, the bike would be happy if I switched to reserve. I did disassemble the petcock and everything seemed to be of working order.

Then I tried hooking the vacuum hose back up and the problem was still there. Which I still can't find a straight answer about this vacuum hose as a low pressure pump...but when I had the vacuum hole unplugged the bike was shooting air out of the cylinder which leads me to believe this helps push gas down the fuel line to the carbs.

That stated, I recently found the main idle screw. When the bike was relative cold but running, the idle screw would dial in the rpms where I want them, but after a long ride, no matter where I turned the idle up to, it would go to 1k rpm and slowly die off.

The newest problem I've found is, I rode on the highway yesterday, and in 4th gear, all of a sudden I was losing power...I down shifted to 3rd and it was hesitating and still losing power...and it finally sputtered and gained some power back (gas was on reserve with at least 4 gallons and the vacuum hose hooked up). This was a pretty scary ordeal, being on the Kennedy at 8pm in chicago while most cars are going 85mphs. I was all the way to the left lane and I had try to make it safely to the right lane...

I know this could be a slew of problems, but I'm trying to figure out if it could be the fuel pressure going to the carbs, the carbs not synced and clean, or something electrical. The only simple thing I have not tried was to change out the fuel filter after the petock, I read some people had trouble with paper elements not feeding fuel to the carbs and cleaning out the air (which was checked off the service in 2009).
 

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One word:

Ethanol

Clean the carbs. It's a yearly ritual on the V45 & V65 Magna's and Sabre's.

Check bobbinalong's explanations of how the Sabre's fuel delivery system works in this thread: http://www.motorcycleforum.com/showthread.php?t=107475&highlight=gravity

There's also a filter screen atop the petcock in the fuel tank. Check to see it that has build-up on it. If there is a layer of surface or thick rust in the tank, then your best best is to use electrolysis on the tank to remove the rust. Just did this to an 86 Magna tank. Works great :)

Your idle should be around 1200RPM. Sync the carbs with the bike warmed up at the specified idle. There's also the chance that someone played around with the mixture screws. Never a good thing to play with. If the lead caps over them have been removed, then I'd set them back at the default factory setting and go from there.

Get the shop or haynes manual for the bike. That will give you all of the specs.

Also, replace the fuel filter. Sitting there for 2-3 years with any gunk in it can make them set up like concrete.
 

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Discussion Starter #3
That's what I thought. I did read that thread on the petcock issue. I'm still convince it's a low pressure pump but the one guy said just gravity...cause when I had the vacuum unattached while the bike was running, it was clearly blowing air out.

I have a new air filter, fuel filter, petcock rebuild kit and a carb rebuild kit coming in the mail. I think cleaning and sync'ing the carbs is past my level of expertise. A shop by my house quoted me $225 for cleaning, rebuild and sync.
 

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Pretty good on the carbs. I know of places that charge $100 per carb + parts.

having to have my roof repaired and fixing a leak in my truck. Once I get those two done, then I install hardwood into our bedroom (currently empty down to the subfloor due to the roof leak).

AFTER that, then I can rebuild the carbs in both of my Magna's and my wife's Shadow 500. Will finally get to ride after that lol!
 

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Discussion Starter #5
found some videos, tempted to give it a go too...but it might be an overwhelming job...


youtube - "V65 Magna Carbs part 2"
 

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I made the installation videos in response to his video on how to remove them:

Part 1: http://youtu.be/5eL1j8diqDk

Part 2: http://youtu.be/2JxDcWqYhyA

Tips if you do it yourself:

  • Ensure you have a manual for instructions and the specs (mix screw setting, float height, etc)
  • Go out and get some compartmentalized storage bins (like this)
  • Print out the carb parts blow-up (found here) ...hit the printer icon to print it out.
  • Label each compartment to the corresponding number on the drawing for ech aprt you remove. This makes it easier to track your parts and where they go.
  • TAKE YOUR TIME!
  • DON'T DO THIS WHEN YOU'RE FRUSTRATED OR TIRED

You will also need a good carb synch tool. I use the carbtune pro. Works great, but you can also get the MotionPro unit or build your own (just google diy carb sync tool).

If you do it yourself and everything works right afterwards, then you will be on your road to learning more and building your confidence. If it doesn't work right, then don't let that put you in misery. Look at it as a chance to learn more than you originally intended. When you know how to work on your own bike, it makes for a more satisfying experience overall :)
 

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Fuel tank venting

Check to make sure the tank is venting OK, too.

Also, like everyone else said. I have a 1st-gen V65 Magna...I love it, but it's also been a real education in carbs/fuel delivery systems.
 
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