T500 Suzuki Right cylinder not firing

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
Mvriit
Still in the Driveway
Posts: 4
Joined: Wed Oct 04, 2017 10:06 am
Country: Suomi
Suzuki 2-Strokes: T500

T500 Suzuki Right cylinder not firing

Post by Mvriit »

Hello, everyone i have been reading these forums for quite a while but never felt the urge to post until now.

So here is the deal, i'm rebuilding my T500 engine and thought i was in the homestretch when couple weeks ago i kicked her up only to find out that the right cylinder isn't running properly.
Some smoke comes from the muffler but it only flows out and doesn't come out in the "popping" manner it comes from the left exhaust, also it doesn't get nearly as hot.
When i proceeded to remove the right hand exhaust about a tea cups worth of black splooge came out of it.
Sometimes the right cylinder fires and a cloud of smoke comes out. This seems to happen especially when the engine is revved.
Strangely even before the engine rebuild the right hand side ran worse than the left. So perhaps it's not related to the engine rebuild?

So here is what i have already done or replaced in the bike.

-Crankshaft rebuilt with new bearings and seals
http://www.ebay.com/itm/SUZUKI-T500-GT5 ... 2749.l2649

-New 72mm pistons and rings
http://www.ebay.com/itm/Suzuki-T500-GT5 ... 2749.l2649

-New left cylinder, as the old had cracked ports, also rebored both cylinders to 72mm
-1400cc gearbox oil modification
-New engine and cylinder seals
-Tympanium regulator rectifier
-New points
-New spark plugs
-5 months old battery

Here is what i have already done and inspected.

-Cleaned carbs during engine rebuild
-Checked wiring and connections during engine rebuild
-Swapped carbs = still left cylinder runs, right doesn't
-Adjusted points gaps to 0.35mm and adjusted timing with a timing gun = no effect
-Checked for spark = both spark plugs have blue spark
-Swapped coils and spark plug caps = no effect
-Swapped condensers = no effect
-Took exhausts off = no effect

Is there something i'm missing or should do? Any help and suggestions are warmly welcomed as this is turning into a quite the mystery.
Last edited by Mvriit on Wed Oct 04, 2017 2:47 pm, edited 1 time in total.
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: T500 Suzuki Right hand cylinder not firing

Post by jabcb »

Charge the battery up. Some T250/T350/T500 have trouble starting & running on both cylinders if the battery isn’t charged up.
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
dollydog
Yeah Man, the Interstate
Posts: 630
Joined: Fri Aug 11, 2017 7:09 am
Country: england
Suzuki 2-Strokes: several gt250 ramairs

Re: T500 Suzuki Right cylinder not firing

Post by dollydog »

i've had much scratching of head with a problem like this and it was coils every time.
either one coil was breaking down or as jabcb says, charge the battery up. i found if the voltage dropped
to less than 12 volts mine would only run on one cylinder, usually the right :D charged the battery up
and it ran perfect. have you thought of using the later coil off the gt500 or gt250x7? one coil and 2 x ht leads.
using wasted spark. i use them on all my gt250's and a cbr600 version on my rgt250. work perfectly when wired
up correctly :D
cheers, dd.
GTS250 road registered. TS250 engine, Ramair frame.
GT250 big bang road registered. Both pistons fire the same time. USD forks.
GT285 road registered. Overbored - 58mm and TS125 +2 pistons fitted.
GT10 road registered. '65 T10 engine, GT250 frame.
Mvriit
Still in the Driveway
Posts: 4
Joined: Wed Oct 04, 2017 10:06 am
Country: Suomi
Suzuki 2-Strokes: T500

Re: T500 Suzuki Right cylinder not firing

Post by Mvriit »

Thanks for the tips, I tried to charge the battery but that didn't help. :( I also swapped the coils around but the problem didn't move to the other cylinder. So wouldn't this rule out coil issues?
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: T500 Suzuki Right cylinder not firing

Post by jabcb »

Use your timing light + a new plug to see if you are actually getting consistent good spark when the motor is running.

You might now have too much oil+gas in the right lower end.
That happened to my gray GT750 because of right cylinder coil problems. Took a while to clear out after I fixed it. Got so much muck & smoke that it actually got hazy. Now runs fine.
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
Mvriit
Still in the Driveway
Posts: 4
Joined: Wed Oct 04, 2017 10:06 am
Country: Suomi
Suzuki 2-Strokes: T500

Re: T500 Suzuki Right cylinder not firing

Post by Mvriit »

Hello again just wanted to say thanks for all the suggestions and that i found the problem.
I had forgot to place the primary pinion spacer on the right crankseal and thus it leaked compression and sucked transmission oil in to the crankchamber. Fixed that up and now it works like a charm. :D
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: T500 Suzuki Right cylinder not firing

Post by jabcb »

Did you have to split the cases to fix it?
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
Vintageman
Expert racer
Posts: 1483
Joined: Tue May 18, 2010 5:38 pm
Country: USA
Suzuki 2-Strokes: Suz, Yam, Honda, Kaw.
Location: New Hampshire

Re: T500 Suzuki Right cylinder not firing

Post by Vintageman »

Did the crank bearing oil holes line up properly with case? I heard initially hole was in wrong location and those bearing needed to be machined/drilled to put the oil supply hole in right place ... Curious when you bought these and if that issue has been corrected.

Thanks
Current Bikes
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
Mvriit
Still in the Driveway
Posts: 4
Joined: Wed Oct 04, 2017 10:06 am
Country: Suomi
Suzuki 2-Strokes: T500

Re: T500 Suzuki Right cylinder not firing

Post by Mvriit »

Hi, again been bit busy but to answer your questions I just had to take off the clutch and primary pinion, luckily.
And I didn't know that there was this issue :x so didn't check that carefully :| I really hope that Cruzinimage has corrected the issue by now and I bought these couple months ago. I'd really hate to tear her apart after just getting her back together.
Post Reply