GT185 pistons

Need some help? Put your question up here. Many years of experience on the board to help you get up and running.

Moderators: oldjapanesebikes, H2RICK, diamondj, Suzsmokeyallan

Post Reply
User avatar
Flywheel
On the main road
Posts: 126
Joined: Mon Apr 22, 2013 6:38 am
Country: USA
Suzuki 2-Strokes: 1974 GT185
Location: SW Pennsylvania

GT185 pistons

Post by Flywheel »

My GT185 got a case of piston slap. Checked the timing, compression (130 for both) and cleaned carbon build up on the piston and head. All okay. Now have to tear down the rest of the top end and measure. Biggest GT185 piston available from Suzuki is 49.50 mm (+.5mm OD). Just curious what brand of pistons other GT185 owners run just in case I have to go over .5mm overbore. Are there other model's pistons that may fit with machine work?
Zunspec4
Expert racer
Posts: 1087
Joined: Tue Dec 16, 2008 11:37 am
Country: UK
Suzuki 2-Strokes: T500R, SV1000S, TS125, Seeley T500
Location: Trowbridge UK

Re: GT185 pistons

Post by Zunspec4 »

Hi flywheel,

Robinsons Foundry (major UK Suzuki dist.) has listings for +0.5mm and +1.00mm genuine pistons so they should also be available from your local Suzuki dealer too.

Cheers Geoff
User avatar
Flywheel
On the main road
Posts: 126
Joined: Mon Apr 22, 2013 6:38 am
Country: USA
Suzuki 2-Strokes: 1974 GT185
Location: SW Pennsylvania

Re: GT185 pistons

Post by Flywheel »

Thanks for the reply but unfortunately the +1mm is currently unavailable at least here in the States.
User avatar
jabcb
Moto GP
Posts: 4240
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: GT185 pistons

Post by jabcb »

There are some 1.0 OS pistons on eBay for very reasonable money. You could order them now & keep them for your parts inventory if you don’t need them.
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
User avatar
Flywheel
On the main road
Posts: 126
Joined: Mon Apr 22, 2013 6:38 am
Country: USA
Suzuki 2-Strokes: 1974 GT185
Location: SW Pennsylvania

Re: GT185 pistons

Post by Flywheel »

Well upon disassembly the right cylinder's piston pin showed signs of brinelling (flat spots) with the piston pin needle bearing falling apart upon removal. I would assume this was the non-rythmatic noise I was hearing not piston slap. Ring end was measured and was within spec (both cylinders) but before re-assembly with new piston pins and bearings I am going to have the cylinders measured.

Would anyone have any ideas what would have caused this and no other internal damage? Lean situation?, just faulty bearing and pin? age? Some previous owner's riding style?
User avatar
Flywheel
On the main road
Posts: 126
Joined: Mon Apr 22, 2013 6:38 am
Country: USA
Suzuki 2-Strokes: 1974 GT185
Location: SW Pennsylvania

Re: GT185 pistons

Post by Flywheel »

Update: Replaced piston pins, bearings, circlips, gaskets and rings (since the top end was disassembled). Noise is gone. :up:
Post Reply