GT250B Best plugs?

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GT250Mike
Still in the Driveway
Posts: 6
Joined: Sun Apr 18, 2021 4:28 am
Country: United Kingdom
Suzuki 2-Strokes: 1977 GT250b

GT250B Best plugs?

Post by GT250Mike »

Hi everyone, new member here.
Just bought a mostly restored GT250B that has been off the road for a few years. Busy sorting through the problems the seller had forgotten to tell me about. Bike is only running on one cylinder and one of the plugs has very poor spark. Going to buy some new ones but not sure which ones are best NGK B9ES are in at the moment.

Any suggestions, info greatly appreciated.
alanr
To the on ramp
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Location: New Zealand

Re: GT250B Best plugs?

Post by alanr »

Ive always used B7HS in my 2 strokes.
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karl pa
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Suzuki 2-Strokes: GT
Location: southeast pa

Re: GT250B Best plugs?

Post by karl pa »

Welcome to the forum
How do you intend on riding it, gentle or wide open?
The early GT250A were having issues with holed pistons. To solve this Suzuki increased the main jet size. The bigger main jet is on the rich side, so it can be unfriendly to gentle riding, but loves wide open.
If you intend on riding wide open, I would stay with B9ES. If you intend to ride gentle or just occasional wide open, you could run a size or 2 hotter plug, to try to help the rich main jet from loading up.
On my GT250B, I went down a size on main jet to make it a little more rideable, but I don't run wide open very much.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
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GT250Mike
Still in the Driveway
Posts: 6
Joined: Sun Apr 18, 2021 4:28 am
Country: United Kingdom
Suzuki 2-Strokes: 1977 GT250b

Re: GT250B Best plugs?

Post by GT250Mike »

Thank you for the replies. From what you say, I will start with the standard plug as a benchmark and see how it goes. I didnt buy it to just burble around on, I intend to ride it like you are meant to.

Advice is appreciated.
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tz375
Moto GP
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Re: GT250B Best plugs?

Post by tz375 »

You might want to invest in a pair of Iridium fine wire plugs and zero ohm resistance plug caps to make the most of that weak ignition system.

You could also fit a relay to get all 12v to the coils and you could also fit a modern ignition system. Cheapest is probably a Dyna which is easy to modify and fit or you could go al out and fit an Ignitech.cz system with new pickups in place of points.
GT250Mike
Still in the Driveway
Posts: 6
Joined: Sun Apr 18, 2021 4:28 am
Country: United Kingdom
Suzuki 2-Strokes: 1977 GT250b

Re: GT250B Best plugs?

Post by GT250Mike »

Thank you for the advice. For the moment I am just trying to get it as rideable as I can as I have found some other problems but I will bear this in mind. I like the idea of electronic ignition but will invest in the iridium plugs and better caps.
Craig380
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Re: GT250B Best plugs?

Post by Craig380 »

You can get non-resistor NGK plug caps really cheap which work best with the Iridium plugs. I ran the Iridiums with non-resistor caps for years in my 380 and they worked brilliantly.
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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