T500 K left cylinder cold start issue

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Ifrew
Still in the Driveway
Posts: 3
Joined: Fri Sep 11, 2020 1:35 pm
Country: United States
Suzuki 2-Strokes: T500 1973

T500 K left cylinder cold start issue

Post by Ifrew »

I've been tuning my 73 T500 and I've got to the point where it's pulling well through the range to WOT and idles well. The bikes carbs are from a 72 with the float bowls from a vented 73 and it has K&N Pod air filters. Currently running with #35 pilot, p4-5fp17-5 and 117.5 main. It took many iterations to get to this point.

Issue I have is that from cold, when I use the "choke", the bike only starts on the right cylinder until I turn off the "choke" then the left cylinder fires up.

I thought it was due to the large pilot jet somi dropped.it back to #30 with same issue. Running with the #30 makes the bike judder when I close off the throttle but when I move it back up to #35 the judder disappears. I assumeed the judder was due to the smaller pilot not delivering enough fuel due to the larger k&N pods.

So now I'm a bit stumped as to why only the left cylinder has an issue. New battery is fully charged.

Any idea folks?

Cheers
Iain
Ifrew
Still in the Driveway
Posts: 3
Joined: Fri Sep 11, 2020 1:35 pm
Country: United States
Suzuki 2-Strokes: T500 1973

Re: T500 K left cylinder cold start issue

Post by Ifrew »

Thought I'd swap the plugs to see if there was any difference. Started first time from cold with choke on both cylinders. Strange..must be a difference in the coil output and the plug/cap resistance..I'll check that next. Turns out one plug cap resistance is 5kohms the left cylinder and the right is 9kohms...ill order up new caps and I'll check the coil resistance.
karl pa
To the on ramp
Posts: 447
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: T500 K left cylinder cold start issue

Post by karl pa »

Good catch.
I use non resister caps and plugs for full spark. Also beware of counterfeit NGK plugs, I buy mine from a reputable dealer.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
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jabcb
Moto GP
Posts: 4111
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: T500 K left cylinder cold start issue

Post by jabcb »

I use either non-resistor caps + resistor plugs, or resistor caps + non-resistor plugs. Fine wire plugs also helps.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
Craig380
Expert racer
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Joined: Mon Dec 01, 2008 2:52 am
Location: Manchester, UK

Re: T500 K left cylinder cold start issue

Post by Craig380 »

If you can get an Iridium equivalent for the stock plugs, I would recommend fitting those.

On my old 380 I experimented quite a bit with various plug types - standard, gold-palladium, platinum and iridium. Using the iridiums with standard gaps (0.7mm) and non-resistor NGK caps was easily the best: the plugs never fouled and never needed re-gapping, literally fit and forget. The bike was running the factory points ignition and coils.
1976 GT380 - wounded by me, and sold on
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
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