Kawi2strokes.com Forum

Hey all, I finished my S3 and got it started. I am having some trouble and I want to get some advice so I don't make the situation worse by guessing wrong.

The background is that I bought the bike used and got the engine running last spring prior to teardown. It ran fine on all three cylinders. I sealed it off and put it on the shelf.

I just finished putting the bike together this weekend. When I tried to fire the engine I initially had it running on the RH cylinder only and it shot up the 7,000 rpm when I hit the kill switch. It did that a couple of times then reasoned that the slide must be stuck in the RH carb. Sure enough, I had the slide in wrong and it was wide open. After that it started up normally and idled pretty well. I adjusted the idle on all three carbs and it seemed to be heating the pipes evenly. I rode it 4 miles with pre-mix in the tank and oil lines full. As I rode it, I lost some power and especially at low rpms - as if I was losing a cylinder at lower rpm. So I put her back in the garage and let it cool down some.

I know, it is a long story but I want you to have all the information.

I pulled the plugs and they were mostly oily but not black/rich. I had to adjust all my cables after the first ride and I looked over the bike carefully. I found that throttle cable for the oil pump control was pulled out in a loop where the cable adjuster is. I think that means I had max oil volume all the time plus the pre-mix. So I put the plugs back in and took it out again. It started up fine, oil control working properly this time. I rolled out and it seemed pretty normal. Then it started missing and acting weird so I switched the petcock to Reserve and thatcleaned it up. I decided to run to the gas station and put some fresh fuel on top of the bit of pre-mix that was in the tank. On the way there I heard a noise like POP - maybe from the exhaust. I only heard it once and it was a bit faint.

I fueled up and checked my pipes. The RH cylinder was not very hot; neither where the fins on the head. The other two cylinders were appropriately hot. I started the bike and rode home on two cylinders. I took the plugs out again. The center plug is showing dark chocolate, the LH plug is dark and wet, the RH plug was just very oily looking. The RH pipe had dark sludge oozing out of it near the tail end when I shut it off. I am wondering if that is somewhat normal for running with a non-firing cylinder on these triples.

I still have good compression using a finger over the spark plug hole in all three cylinders. That was just a quick check I wanted to do to see if I killed the RH cylinder. It could just be a fouled plug or a spark problem on the one cylinder.

I don't want to screw this up by jumping to the wrong conclusion. What are your thoughts and what would you check before running this engine again?

Thanks.

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Rotortech
Indianapolis
1974 S3

The spark isn't very strong on an S3. It is easy to foul plugs. Premix & pump together will aggravate that problem.
What I would do...
-Get rid of all premix, including that in the float bowls
-Check points contact by putting a meter across the points to check for zero volts when ignition is on and points set is closed. Points, even new are sprayed with inhibitors, can become contaminated causing "popping" from incomplete contact. Clean them with rubbing alcohol.
-Insure that battery is fully charged
-Put in new plugs properly gapped
-Set carb sync & airscrew: http://www.3cyl.com/mraxl/manuals/carbtune/carbtune.htm

Edit: You may need to run the piss out of it to clear out all that crap that has accumulated in the crankcase.

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Answers are here: http://kawatriple.com/

I recently started my S3 after re ring it, I used pre mix and oil injection as a precaution for the first start up, it gave me a smoke machine, I dumped the pre mix.

Learning carb sych, throttle and choke cable routing and adjustment has helped a lot, my bike runs strong revs excellent idles excellent but its still a smoke machine but not as bad as when I had pre mix and injector oil, I think it needs to be ran a bit to really know where it stands.

Don't know if that will help but your not alone, tuning a triple is a bit more involved than I had thought, much to learn still, mraxl's resource site is the holy grail of info.....

Here's my S3 thread on KTOG in case ya want to have a look.

http://kawasakitriples.myfastforum.org/ ... highlight=

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1975 S3 project bike
1974 H1 project bike
1972 Yamaha R5
1974 Yamaha RD350

mraxl - I strongly suspected plug fouling and I will follow your advice. first I will dump the fuel into my lawn mower gas can then drain the carbs and get a few sets of new plugs. I was just paranoid about sticking a cylinder during the first start up. Now I have plenty of oil in there.

And, yes, I will run the piss out of it when I get it sorted out.

Jack - thanks for your thoughts. I spent a lot of time routing and re-routing my cables and they are all adjusted properly.

Thanks guys - I knew I could count on some good advice.

By the way - On the maiden ride I went four miles and a guy in a pick up truck followed me home. I pulled into my garage and he parked in the street at the end of my driveway. He yelled "Is that a triple?" I said "You bet it is." That's all he wanted to know.

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Rotortech
Indianapolis
1974 S3

Zambia (Ian) sent me a PM to inform me that on the S3 it is possible to get the slides mixed up. This causes the slides to be in backward and they foul plugs almost instantly. He said he went through a bunch of spark plugs before he figured it out. I am almost sure that I have made this mistake and will be checking the carbs out today.

Thanks Ian.

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Rotortech
Indianapolis
1974 S3

From the manual:

"Mounting Carburetors

Mount carbs and assure there are no air leaks from missing cap gaskets, loose fit, etc. Set all needle clips to the same position. ref:http://kawtriple.com/mraxl/carbspec.html Be aware that some carbs (S series) will allow slides to be fitted backwards and the clamp space may need to be cut wider to allow tight clamping.

Some models have a phenolic heat insulator sandwiched between two gaskets at the base of the intake manifold to prevent excessive heat transfer from the cylinders to the carbuetors.

Gaskets should be present on all carb caps. A drop of super-glue will insure they stay in proper position."

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Answers are here: http://kawatriple.com/

Going out on a limb here not an expert,

On my S3 the center carb and the right cab are the same the left carb is different if you put the slide from the left carb in a center or right it will be backwards same if you put a center or right in a left, my slides can not be installed backwards but they can be installed in the wrong carb.

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1975 S3 project bike
1974 H1 project bike
1972 Yamaha R5
1974 Yamaha RD350

That's normal, you always have to take care that the slides are correct for your carbs. Always left and right once,

Regards
Ralf

Thanks Ralf and Jack. I know that I mixed the slides when I put them on this time and did not take care to keep each slide with the proper carb.

I will correct that problem and spend some time tuning.

I appreciate this forum and all the great people on it!

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Rotortech
Indianapolis
1974 S3

i had the same issue on the carb slides on my s2 once...took a few hours to figure what i did wrong..

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downwind of three mile island