T500 - Bringing Back to Life - Bogging/Dying Issues

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BlackBearT500
On the street
Posts: 11
Joined: Mon Mar 13, 2017 7:24 pm
Country: United States
Suzuki 2-Strokes: 1971 T500

T500 - Bringing Back to Life - Bogging/Dying Issues

Post by BlackBearT500 »

Hi,

I was just given a '71 T500 by an old family friend (my first Suzuki out of many bikes throughout the past). I have replaced the battery, cleaned out the carbs very extensively, inspected, cleaned and primed the oil pump/lines, replaced the banjo O-rings with stat-o-seal washers from McMaster Carr, derusted the gas tank, replaced the spark plugs, cleaned grounds, and trimmed the plug wires, replaced the petcock and fuel lines/capped off the vacuum port from the old fuel diaphragm, cleaned the points and set gap/ignition timing to be dead-on.

I just tried starting it, probably for the first time in 20+ years. It started right up on second kick and sat and idled for a few minutes with no issues (nice and smoothly). As soon as I twisted the throttle the slightest bit, it bogged and almost died. I inspected the oil lines and noticed the rightmost line was getting small air bubbles in it after the bogging issue happened (again, I made sure to bleed/prime before starting). I attempted to start the bike again after 30 or so minutes and after another attempt to prime the rightmost line leading into the case; however, the bike took longer to start and the bogging issue seemed worse the second round of starting. There was no way to twist the throttle past 1/16-1/8 turn without it dying.

I made sure the carb slide cutouts were faced towards the rear of the bike, to rule out incorrect carb slide installation. Also, for the '71, I have read the needle clip should be set to the 2nd and 3rd positions, which is it? - it is set to the third position down now, but looks like it has been moved in the past (I noticed slight scarring around the clip positions from, I assume, pliers used to pull the clip). Also, the air screws are currently set to 1 & 1/4 turns out.

So, I guess my question is: what could be causing this bogging issue with a small twist of the throttle?

Any help would be greatly appreciated because I really look forward to bringing this Titan back to life!

Thanks,
Trenton
Suspensionking
Around the block
Posts: 89
Joined: Fri Jan 01, 2016 7:21 am
Country: Switzerland
Suzuki 2-Strokes: T500 Suzuki, AJR Bultaco, Honda NS475

Re: T500 - Bringing Back to Life - Bogging/Dying Issues

Post by Suspensionking »

Hi Trenton,

What size are your pilot jets? did you remove them and clean them. Sounds like its that area of carbonation that might cause what you describe.

Cheers

Eamonn
BlackBearT500
On the street
Posts: 11
Joined: Mon Mar 13, 2017 7:24 pm
Country: United States
Suzuki 2-Strokes: 1971 T500

Re: T500 - Bringing Back to Life - Bogging/Dying Issues

Post by BlackBearT500 »

To be honest, I was confused about the Mikunis on the 500 (I've only experience with Keihins old CBs and more modern bikes). I know I got the main jet, needle jet and seat cleaned, along with setting the correct float height. However, I did not locate a screw-in pilot jet anywhere in the bowl of the carb. I did notice a pressed-in tube with a fairly wide inside diameter that was pressed into the base of the carb, so I did clean that.

Forgive my ignorance, but where exactly would the pilot jet be located on the '71? And what does it look like? Is it the pressed-in piece?

I'm still learning, and I certainly appreciate the help!

Trenton
Suspensionking
Around the block
Posts: 89
Joined: Fri Jan 01, 2016 7:21 am
Country: Switzerland
Suzuki 2-Strokes: T500 Suzuki, AJR Bultaco, Honda NS475

Re: T500 - Bringing Back to Life - Bogging/Dying Issues

Post by Suspensionking »

Hi

When you are looking at the carb inverted with the float bowl removed, in the center is the main jet and just in front is a smaller tube and set deep down in there is the pilot jet. They can be difficult to get out of the carb has been unused for some time. a flat blade screwdriver is needed and you may need to warm the outside of the tube if it will not unscrew without a lot of force.

hope that helps.

Eamonn
BlackBearT500
On the street
Posts: 11
Joined: Mon Mar 13, 2017 7:24 pm
Country: United States
Suzuki 2-Strokes: 1971 T500

Re: T500 - Bringing Back to Life - Bogging/Dying Issues

Post by BlackBearT500 »

Eamonn,

I bet that's the culprit! I did not remove anything that fits that description. I did, however, make sure I did not miss anything when taking the carbs apart (I cleaned what parts were obviously removable and cleaned all passage ways with a small guitar string); so, I bet the pilots were either completely gummed over and hidden, or they were not reinstalled by the previous owner. When tinkering with them, I wondered where the pilot jets could possibly be.

The previous owner told me the bike was doing the same thing when they had it running - starting, idling for a good bit, then bogging out and dying. So it's possible they forgot about the pilot jets, I suppose.

When I get the chance over the weekend to pull the carbs and double check them for the hidden pilot jets or lack thereof, I will definitely type back and let you know.

If there is anything else I should look out for while the carbs are off, please let me know.

Again, thanks for all of your help! I doubt I would have ever thought of that as a potential issue.

Trenton
BlackBearT500
On the street
Posts: 11
Joined: Mon Mar 13, 2017 7:24 pm
Country: United States
Suzuki 2-Strokes: 1971 T500

Re: T500 - Bringing Back to Life - Bogging/Dying Issues

Post by BlackBearT500 »

Hi,

Just wanted to say thanks again! The T500 starts, idles, and rides very well now with great throttle response, etc. The problem ended up being one of the pilot jets having a clog.

Thanks for helping me get this bike back on the road!

Trenton
Suspensionking
Around the block
Posts: 89
Joined: Fri Jan 01, 2016 7:21 am
Country: Switzerland
Suzuki 2-Strokes: T500 Suzuki, AJR Bultaco, Honda NS475

Re: T500 - Bringing Back to Life - Bogging/Dying Issues

Post by Suspensionking »

Nice glad to read it all works well now out :up:

Eamonn
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