T500 won't run past 3k rpm

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mario03srt
On the street
Posts: 43
Joined: Sat Oct 06, 2012 7:01 am
Country: USA
Suzuki 2-Strokes: T500

T500 won't run past 3k rpm

Post by mario03srt »

All,

I have recently got my barn bike back together and fairly tuned. It now starts in June waether w/o any choke on a 1st kick, idles well, and throttles very nicelyon the centerstand w/o any load. On the street it is another story. The bike will not accelerate past 3-3500 rpm, no burps, stutter, pop, surge, nothing. The bike has pod filters, jemco chambers, mild port and polish, honed/rings, new points/condensor, rebuilt carbs, new pingel petcock, chem cleaned gas tank, battery, etc.

I'm now at a loss as to the problem. Bike is a 69 T500 mkII with 16k on the odometer.

Any ideas or answers/questions are greatly appreciated.

Thanks,

Marion
mario03srt
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Joined: Sat Oct 06, 2012 7:01 am
Country: USA
Suzuki 2-Strokes: T500

Re: T500 won't run past 3k rpm

Post by mario03srt »

I should add that the Carbs have a 162.5 Main, 35 Pilot, Stock Needle jet. With Pod Filters.
Vintageman
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Re: T500 won't run past 3k rpm

Post by Vintageman »

mario03srt

Any chance you swapped the left and right pistons when putting it back together?

Same question with carb slides ... are they backwards

Else someone had a similar problem, not as bad maybe and his timing was off.
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keithwwalker
On the street
Posts: 47
Joined: Sat May 23, 2009 10:25 pm
Location: Portland OR

Re: T500 won't run past 3k rpm

Post by keithwwalker »

Did you ever figure this out?
I have a similar problem.
Won't run under load beyond half throttle.
Vintageman
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Re: T500 won't run past 3k rpm

Post by Vintageman »

keithwwalker,

What is you set up? Pods for example.

Has it ever run rights. Is it stock, Did you do any engine work, What happens after half throttle describe "sounds" better for example. Does it cut out, pop or backfire, gurgles along or drowns out until it stalls

Is it RPM related or throttle position related issue. I mean if you are 1/4 throttle 6000 rpm and crack WOT same as 3500 RPM and crack WOT same issue or not?
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),
keithwwalker
On the street
Posts: 47
Joined: Sat May 23, 2009 10:25 pm
Location: Portland OR

Re: T500 won't run past 3k rpm

Post by keithwwalker »

I have a thread here, it is quite interesting if the issue is what I think it is:
viewtopic.php?f=2&t=11701" onclick="window.open(this.href);return false;

fwiw, it is stock, first test rides - tell me what you think of my theory.

Thanks all.
Vintageman wrote:keithwwalker,

What is you set up? Pods for example.

Has it ever run rights. Is it stock, Did you do any engine work, What happens after half throttle describe "sounds" better for example. Does it cut out, pop or backfire, gurgles along or drowns out until it stalls

Is it RPM related or throttle position related issue. I mean if you are 1/4 throttle 6000 rpm and crack WOT same as 3500 RPM and crack WOT same issue or not?
greens888
On the street
Posts: 18
Joined: Tue Aug 25, 2015 3:02 am
Country: Australia
Suzuki 2-Strokes: 74 T500 74Re5 74Mach111

Re: T500 won't run past 3k rpm

Post by greens888 »

Hi, for what it`s worth, this is what I`d do; Its obviously getting spark. Its getting fuel. What changes at 3grand rpm? Could be timing, I`d check that as it is quite easy with a dial gauge and the timing marks on the magneto. If pretty close, wipe it off the list. Next; run at max throttle, which you say is 3 grand, for a 60 second run and stop and pull both plugs. People have all these rules for plug chops etc, but they complicate it too much. The colour of the plug will obviously tell what is happening in the combustion chamber and is my main method of diagnosis on any 2 stroke once I`m confident everything is pretty close. If wet as I suspect, then too rich and I`d try a much smaller main jet, and probably also go one notch leaner (up) on the jet needle. Run again and see what happens. If no change, then we`re looking in the wrong area. But if a change then we`re on the right track- is it better or worse, what colour are plugs at WOT? Obviously just work leaner or richer until you get close. Presuming float level is correct, different year models have dif float levels remember. If none of this helps then you have a different problem, I`d look at; blocked air jet or clogged needle jet, pull needle jet out and thoroughly clean, they get crap built up in them; Run without pods for a short distance, see what happens; check earth on coils; new (correct) plugs is a definite possible solution; last thing I can think of which got me once on my mach 111 was a blockage in the exhaust baffles. Hope one of these points helps. Steve.
titan performance
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Re: T500 won't run past 3k rpm

Post by titan performance »

Are your main jets hexagonal?
Keeping old 2 strokes alive !
keithwwalker
On the street
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Joined: Sat May 23, 2009 10:25 pm
Location: Portland OR

Re: T500 won't run past 3k rpm

Post by keithwwalker »

I did a 100 mile ride 2 weekends ago, see my other thread mentioned above. It seems the right center crank seal is bad and letting gear oil into the chamber (this is based upon plug readings - the left is normal).

Is this a characteristic of the bike, that the right seal goes bad before the left? I think that the rebuilder either didn't split the crank, or assembled it wrong and ruin the seal during pressing. It was years since rebuilding it, so that may be an issue as well...
greens888
On the street
Posts: 18
Joined: Tue Aug 25, 2015 3:02 am
Country: Australia
Suzuki 2-Strokes: 74 T500 74Re5 74Mach111

Re: T500 won't run past 3k rpm

Post by greens888 »

I don`t know if you are still battling the t500, could you update us as I am interested. The fact that it starts first kick in winter with no choke tells me it is rich. Are you going down the blown crank seal way? I was interested in the Blue Devil Oil product which is supposed to fix slightly worn or hard seals. Steve.
greens888
On the street
Posts: 18
Joined: Tue Aug 25, 2015 3:02 am
Country: Australia
Suzuki 2-Strokes: 74 T500 74Re5 74Mach111

Re: T500 won't run past 3k rpm

Post by greens888 »

Oh and I forgot to ask you if you have checked that the chokes are disengaging properly.
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