Page 1 of 2
1973 t500 wont start
Posted: Tue Mar 24, 2015 9:58 pm
by freedom0226
Newbie here so some of this may seem dumb...I have read all i can and downloaded the manual , also did a search before posting.
1973 suzuki t500 . i purchased this bike from a co-worker who says all it needed was the fuel tank cleaned and a new battery... ive seen old videos of the bike in action.. Please let me know if i left anything out.
1.I have installed new ngk plugs and cleaned the contact points and confirmed i have good strong spark. i also did a compression test and have 95 psi on left cyl and 105 on right cyl.
2. i have a brand new battery which meets specs 12v 7ah and i have a booster connected at the same time
3. i have cleaned out my fuel tank (rust issues), cleaned the petcock all ports are clean and works as should per manual. No leaks
4. This is where i get stuck. im new to the carb world and i have viewed videos / read all about carbs to get a good understanding but i believe i am not getting any fuel, i have drained the fuel bowl on both sides and have good clean fuel coming out. i have not taken apart the carbs yet until i get some info before i really mess things up. i hit both sides with a rubber mallet in case the float was stuck.
how can i confirm i have fuel in the right place? i even tried starter fluid and still nothing..
Now this may be a dumb question... i have another post that my green neutral light does not turn on . hence im not quite sure if i am in neutral other than i keep shifting down until i hit the gear with no resistance . Will this bike ONLY turn on in "N" ? at this point i dont know what else to do before i just take apart the carb which i dont think i have to.. i still have to diagnose the neutral thing but i figured let me get this started before i go taking things apart just for a neutral light....
I have spark , i have compression , fuel is ? but shouldnt i at least get a little hiccup of life with the starter fluid. ?
Re: 1973 t500 wont start
Posted: Tue Mar 24, 2015 10:16 pm
by freedom0226
also i cant find any good pics of carbs but the left carb with the vacuum port seems to not have a throttle valve inside.. is that normal.all i see is the valve needle in the middle but no throttle plate or valve... ... in the diagram i posted its part number 23. i will post up pics of my actual carb in the a.m
Re: 1973 t500 wont start
Posted: Tue Mar 24, 2015 11:01 pm
by oldjapanesebikes
freedom0226 wrote:......t the left carb with the vacuum port seems to not have a throttle valve inside.. is that normal.all i see is the valve needle in the middle but no throttle plate or valve... the right carb looks normal but no butteryfly in there also.... in the diagram i posted its part number 23. i am new to this so i was expecting to see buttery fly valves . the carb does have an adjustment screw for the buttery fly valve but its serving no purpose. i will post up pics of my actual carb in the a.m
Assuming you have the right type of carburettors on the bike - with the throttle grip released, the slides should be all the down to the bottom of the throat. If the slides are stuck at the top of its travel in the carburettor housing, then the engine will not start.
I would suggest you first verify that the slides are free - and I suppose also actually there, although you would not be able to see the needle if they weren't there at all as the slide is what holds them. Check that they do close off the throat and move up and down with the throttle grip at about the same time. After a long storage, it is a given you will need to clean the carbs - but once the slide question is answered you should be able to get it to cough, even if it doesn't run very well.

Re: 1973 t500 wont start
Posted: Wed Mar 25, 2015 5:09 am
by rngdng
I also suggest a thorough carb cleaning. The jets are very likely clogged. The pilot jet is smallest and most easily clogged. It also happens to be the one you need for starting and low throttle settings. The pilot is small, brass, and very easy to strip the head out. BE CAREFUL and make sure you use the correct size screwdriver. Soaking the carb body in Berryman's carb cleaner overnight will make things much easier.
Lane
Re: 1973 t500 wont start
Posted: Wed Mar 25, 2015 9:50 am
by freedom0226
man i am loving this site with quick replies thanks guys i am posting pics now..ok so you can see the left carb has no throttle valve prob stuck wide open as mentioned and the right side appears normal. both drain fuel as should and does not appear dirty but i will remove them and be as careful as possible as this will be my first time taking apart a carb . is anything going to fly out during disassemble - springs , clips , retainer etc etc...the appearance of fuel on the outer lip is actually starter fluid from yesterday ..
One more thing is there ANYTHING i can try before i disassemble this carb..Let me know if you need additional pics... its not the nicest bike ive seen posted here but i got it dirt cheap and would love to have it for summer time.
Also the neutral question. does it have to be in N for it to start . as of now i am unsure i am truly in N
Re: 1973 t500 wont start
Posted: Wed Mar 25, 2015 11:20 am
by titan performance
The bike will have to be in neutral to start on the kick start, or you will be trying to turn the gear box and rear wheel. You can't just pull the clutch either, as that will disengage the kick starter. The green light not illuminating could be the bulb, or the neutral switch which is inside the left hand engine cover near the front sprocket. I'd check the bulb first, but it's not going to stop the bike running.
I don't think there's any short cut.....get the carbs off and sort them. The left one has definitely got a stuck slide...get the bowls off, and clear the jets. As someone else said, the pilot jet is tiny, and will need something like a hair brush bristle to clear it....
Re: 1973 t500 wont start
Posted: Wed Mar 25, 2015 2:47 pm
by freedom0226
ok update..... the left carb was indeed stuck at WOT. i cleaned up the left carb completely and reinstalled . made sure the spring is controlling the throttle valve. both carbs snap right back when you release the throttle and now it feels like it wants to start but all i got was a loud back fire on two separate attempts. every now and then i also get kick back feeling from the kick starter i dont think the timing is off because ive seen video of the bike running prior to purchase only difference is its been sitting about 1 year or so . Some progress has been made but i dont want to keep cranking it and getting that loud back fire.... Also the only time i do get any hopeful movement its because while i kick start i have WOT at the handle.
Re: 1973 t500 wont start
Posted: Wed Mar 25, 2015 4:56 pm
by titan performance
Are you using fresh petrol? Modern fuel does not age well. I would be inclined to check it's timed correctly-ish. It's so easy, why not do it? Remove the alternator cover, and check the points gaps first. Take out both plugs. Put the one you are going to check into the cap and earth it on the motor. Turn the ignition on. Use a ring spanner on the end of the crank to turn the engine until L or R, (which ever you are checking), appears in the little round window at the top of the alternator. There are scribe marks by the letters that should align as the plug sparks. You will see, or hear the spark crack....adjust the plate around the crank accordingly.
If you are happy the carbs are clear, fuel plus spark, should equal run ! Be sure you have the slides in correctly, as they have possibly both been out......cutaways to the rear !
Keep us posted.
Re: 1973 t500 wont start
Posted: Wed Mar 25, 2015 6:56 pm
by freedom0226
i have 2 gallons of 87 fuel inside. i took the carb apart and cleaned both jets , verified nice spray from jets and reinstall. cleaned fuel bowl, check floater play all good. reinstalled . i would like to place an inline filter before the carbs but i cant find a small one that wont interfere with the lines just to keep things clean.
As for the timing etc..i am new to the world of suzuki and bikes i have to read up on the timing before i go messing things up. i am perfectly fine with setting time on older cars with points and distributor rotation to find timing . The points gap im ok with but i have to familiarize myself with timing the bike... if you have any links that go more in depth that would be great im going to do a search on it . its dark in nyc already so i will continue tomorrow...
i really appreciate all feedback
Re: 1973 t500 wont start
Posted: Wed Mar 25, 2015 8:34 pm
by parksie
It might sound dumb but are you sure the coils are wired to the correct cylinders. Just swap the leads to the plugs over and see what happens.
Re: 1973 t500 wont start
Posted: Thu Mar 26, 2015 6:24 am
by jabcb
parksie wrote:It might sound dumb but are you sure the coils are wired to the correct cylinders. Just swap the leads to the plugs over and see what happens.
Suzuki mounted the coils on the twins (T250/T350/T500/...) in both directions, with some facing forwards & others facing backwards.
In one direction the left coil goes to the left cylinder & in the other direction the coil HT leads are crossed.
Re: 1973 t500 wont start
Posted: Thu Mar 26, 2015 10:13 am
by freedom0226
[quote="Suzuki mounted the coils on the twins (T250/T350/T500/...) in both directions, with some facing forwards & others facing backwards.
In one direction the left coil goes to the left cylinder & in the other direction the coil HT leads are crossed..[/quote]
i want to kill who ever made that coil set up... i guess removing the carbs completely and giving them a thorough cleaning made a bigg.. difference also but YESSSSSSSSS it runs.. i soaked the carbs after cleaning them all night installed them and the bike started rigt up just now.......... Im soo glad i didnt have to mess with timing but i would still like to learn how to....
Now i turned it right off because i did notice that the oil tank clear line leading to the oil pump wasnt moving -- sucking oil in.... Should this line start sucking oil in upon start up... i also gave the throttle some quick snaps and no suction movement..i did place fresh oil in the tank...i know these have been silly questions to experts as yourselves but all your help thus far has been great for this being my very first bike....
Also now that i know the bike starts i can start doing more..i want to change the oil in the gear box / trans / clutch - it has soo many names...Manual calls for 20/40w but all i find at autozone is 20/50w 4 stroke gear box oil.... is this ok to use..
Re: 1973 t500 wont start
Posted: Thu Mar 26, 2015 10:47 am
by ConnerVT
Posted this in another forum, but I'll put it here for you:
Suzuki service manuals recommend 2 ways to do it. The most accurate is to use a dial indicator mounted in the spark plug hole. You adjust the points to just open when the top of the piston is 3.4mm away from TDC.
Less accurate, but nearly as good for most people just riding the street, is by using the L and R marks on the generator's rotor, visible through the round window of the stator. That mark corresponds with the 3.4mm you would measure with the dial indicator.
Pretty simple to do:
-- Set both point gaps to spec, and equal to each other (gap can affect timing)
-- Loosen both spark plugs (makes easier to turn engine by hand with kick starter)
-- Remove wire from both points (isolates from bike's electrical system)
-- Attach volt meter to one of the points (where you just removed wire) and to ground (any metal on the bike). Set VOM to measure resistance. If you don't have volt meter, anything that can test continuity will work.
-- Slowly turn motor with kick starter. The points should just open when reaching the mark corresponding with the cylinder's points you are testing.
-- Loosen the necessary screw(s) (not the one that holds the point gap) to move the points up/down the stator as needed, to adjust. (Different setups on different bikes)
-- Repeat until points *just* open when at the mark.
-- Check that the point gap is unchanged.
-- Repeat above for the other cylinder's points.
-- Reattach wires to points.
-- Re-tighten spark plugs.
-- Test and profit.
As for the oil pump:
There should always be oil in the line from the oil tank to the pump. It is gravity feed, but sometimes you need to remove the bleeder screw to get any ir out that may be preventing flow. Removing the tank line from the pump will at least get the line itself full (and create an oily mess in the process).
You can search this site for multiple discussions on how to prime T500 oil lines. My preferred method is to disconnect the lines from the cylinders/crankcase, remove the pump from the crankcase, pull the flow control lever to full throttle, and use an electric drill with the largest flat blade screwdriver bit I own to drive the pump (watch for correct rotation). Let the oil fill the lines, then reassemble.
I then like to drain the tank (remove from the oil tank itself) the current oil of one color, and replace with a different color oil. You should then see that new color working its way down the oil lines after a few minutes of running.
And for some light reading:
T500 Service Manual
Re: 1973 t500 wont start
Posted: Thu Mar 26, 2015 11:23 am
by freedom0226
ok i will do a search on that.... but all i can find locally is 20-50 4 stroke gear oil for motorcycles .. is it ok to use this in the gear box.
http://www.autozone.com/motor-oil-and-t ... 93839_0_0/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
or can i use this royal purple 75w -140 gear lube
http://www.autozone.com/greases-and-gea ... 68917_0_0/" onclick="window.open(this.href);return false;
thanks for the link i actually purchased the manual online on cd and pdf. i am reading now how to do it from the inlet line to the pump. it says to remove line and allow to bleed till line is full but if its gravity fed should oil start coming down from the tank.... i took the cover off and it seems i will have to remove the right side carb to get to the other bolt for the pump removal..or i should just be able to swing it to the side.. i will take a pic upon removal of oil pump i am unsure which screw to hit with the drill
Re: 1973 t500 wont start
Posted: Thu Mar 26, 2015 2:33 pm
by Coyote
Oil pumps do not suck oil. It is gravity fed only. Bleed your feed line at the pump to remove all air possible. Not familiar with your bike, but most pumps have a bleed screw which allows the IN line to fill. Use a little pre-mix till you are sure your pump is working correctly.