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Hi. I am trying to fix up a 1974 Suzuki TC100. It runs, but I notice the following problem. If anyone has any input, it would be greatly appreciated.
When I start the bike, it runs fine. Its a two cycle engine, so it puts out a little smoke. Once I get riding, I can go about 4 miles with good power, but then I notice the bike seems to sputter and misfire as I go faster toward the higher end of EACH gear. At the low end of each gear, it seems ok. If I keep driving it under the mentioned conditions, it will eventually stall on me when I get to a stop sign. Then I have to wait until the bike cools down and it will start up again. However, after the restart, it reaches the sputtering point much quicker because the bike is already warm. Lucky for me, I was able to drive it home in 4th gear going about 25 miles per hour.
Joined: Oct 03, 2005 Posts: 1595 Location: Marshall, MI
Posted: Wed Sep 23, 2009 1:48 pm Post subject: TC100
Welcome and cool bike. The TC100 Suzuki has a rotary intake carburetor on the right side of the engine then the aircleaner is above the engine. Of course, the carburetor must be removed and cleaned with jets removed, etc. and the air cleaner must be cleaned as well. Could be that some mice had a party in the air cleaner. Anyway, change the spark plug as well and only use the correct NGK plug. Two strokes foul plugs easily and can run on a fouled plug sometimes. Carbon can become an issue if it has numerous miles on it. Fresh gas. It could be so many things, start there and see what's up. _________________ You only go around once in life, but if you do it right, once is enough!
Joined: Nov 02, 2008 Posts: 1085 Location: New Zealand
Posted: Wed Sep 23, 2009 2:23 pm Post subject:
I'd suggest you look at the exhaust side of things as well as the intake/gas side. It is very easy for the exhaust to get gunged up on those little two strokes and not allow the emissions to escape freely.
Joined: Aug 14, 2009 Posts: 10 Location: Lebanon, Pennsylvania
Posted: Wed Sep 23, 2009 3:19 pm Post subject:
Thanks for the info. I did pull off the exhaust once to clean it, and I noticed that there was something clunking around on the inside. It was as if some piece had become loose and was sliding around in there. Unfortunately, finding a new exhaust is difficult because it seems like a rare bike these days.
If you pull the plug when it's hot and stalled out that will tell you alot, wet means spark interuption meaning points/condensor, whitish means super means lean which is probably needle and seat or float level otherwise carb issue, black and dry means over rich and fouled out the plug remedy jet size, float level.
I've always been told that if a bike runs fine until it gets hot then the condensor is suspect, but that's my vote. With me it's always a goose chase thru the bike till I find the problem though. The plus side is I know my little t20 inside and out now, and can hear the problems coming, like when one cylinder is starting to foul out.
By any chance have you done a compression test on the Suzuki ? You mentioned it smokes as all two strokes do , to a point .
Blowby could cause some of these issues . I rode the 72' tc 90 when I was a kid . I could insult the yamaha 175's in our neighborhood ,
not in a straightline race , but , through the trails - used to piss them off good !! Yours being vintage , you probably don't want to try
this , but , we use to notch out an 1/8 th inch from both sides of the rotary disk . This started dumping fuel sooner and the duration was
extended . Then some careful jetting , finding the right plug and an expansion chamber and well , this was the fondest memories of any
bike I have ever owned . Good luck to you , and keep us posted . Any pictures ?
Joined: Nov 02, 2008 Posts: 1085 Location: New Zealand
Posted: Wed Sep 23, 2009 6:38 pm Post subject:
Knowing that something is loose in the exhaust adds to my belief it needs to be checked and de-gunged.It may need to be cut open by a suitably skilled engineer and sorted...then patched back together.These bikes run very crisply when everything is in good shape but soon 'load-up' and choke on their own fumes when things aren't 100%.
Joined: Oct 03, 2005 Posts: 1595 Location: Marshall, MI
Posted: Wed Sep 23, 2009 6:56 pm Post subject:
tcanough, porting a rotary valved motor is insane. I never heard of that but makes sense. How many did you blow up?? HeHeHe... Like the 350 Big Horn blow ups! Now that was a rotary piece of sh...machinery. _________________ You only go around once in life, but if you do it right, once is enough!
Joined: Nov 02, 2008 Posts: 1085 Location: New Zealand
Posted: Wed Sep 23, 2009 7:37 pm Post subject:
350 Bighorn? Now if you wanted to experience pure fear all you had to do was open the throttle on a 350 Bighorn on broken terrain and suddenly you knew what fear was!
Posted: Wed Sep 23, 2009 7:45 pm Post subject: HEY STEVE ;
Back then , I barely could come up with enough money to put gas in the Suzuki .
I read an article in dirtbike magazine about the rotory disc induction motor .
It made sense to me , I don't have to buy anything to add , just take something away . I never blew
up a rotory disc engine , but , on my 74' kawasaki 175 , I created quite the finiky beast . I also opened
up the leading edge of the rotary disc and the trailing edge 1/8 inch . These were powerful bikes to begin
with and it would flat out scream. I have never had more fun than on the little Suzuki , best bike I ever owned !!!!
Rotory disc induction has lots of merits and a few drawbacks , but I prefer it over anything else .
You just sold me , I'm going to be searching with a passion until I find one of those bighorns !! Is that what I think , a rotory
disk induction motor of 350 cc ? And that was a cool race !!
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