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I have a 1990 suzuki katana 750 it wont start I have fuel spark but the compression 90 psi on one cyl and 50 on the other three whats up?

Posted by Scott on


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Gregg Mahin

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Hi, Scott and the usual suspects are:
1. Improper valve adjustment.
2. Broken or loose cam chain.
3. Loose or broken cam sprocket.
4. Bent, burnt or stuck valve.
5. Blown head gasket.
6. Piston failure.
7. Broken connecting rod.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.

Posted on Aug 17, 2020


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Takes 10W40 motorcycle oil, and should be about 4-4.5 quarts.

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Gino Cussen

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SOURCE: compression test on a gsx1100 suzuki katana

156 to 213 pounds per square inch.

Posted on Mar 26, 2009


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SOURCE: ''I am looking for 1983 suzuki GSX 750 S Katana Owners manual''

Google " service manuals suzuki "
or go to
or try your local library. Often guys will donate manuals to the library.

You might find a free pdf service manual on this site, they have a ton of them.

Please rate this solution. Thanks!

Posted on Apr 05, 2009


  • 4 Answers

SOURCE: backfire during shifting between gears

could be few probs, carbon build up on piston crown try a good cleaner fuel additive, your exaust is leaking or blowing allowing air to be sucked back in on revdown as well as you could have a inlet fault overfueling leaving to much unburnt fuel to enter your exaust, might be simple fix by just replacing the air filter and checking for burn marks around the air intake.

Posted on Jul 10, 2009



  • 4565 Answers

SOURCE: suzuki gn125 wont start. checked carb, cdi, coil.

Check the valve adjustment. If a valve is standing open just a little, the compression will be too low to start the engine. Check fuel delivery by dribbling a little gasoline into the carb and try starting the bike. If it starts and runs for a second or two, you're not getting fuel into the cylinders. Check you carb again.

Posted on Oct 19, 2009

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1 Answer

1992 suzuki 750 it's got spark but won't start, what could it be?

engines require three things, spark-at the right moment, fuel, and compression. If you're sure you have a strong and consistent spark, move on to your fuel. Drain everything you can and start with fresh NON OXYGENATED (no alcohol) fuel. In recent years 1/2 the troubles I see is from poor quality fuel. I spray a shot of starting fluid into the airbox and if the bike starts or at least coughs that tells me I have a fuel problem. Last but not least perform a compression test. The psi isn't as important as each cylinder should be with 7lbs of the rest.
After an attempt to start, pull the plugs, are they wet or dry? If wet crank the engine over for 20-25 seconds with the plugs out and re attempt a start choke off and a light shot of starting fluid. Give this a look and report back your results. Good luck

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Hi, Foxygirl309 you need "FIVE" things in order for a cylinder to run properly:
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4. CAM TIMING: confirm your timing marks are aligned to see if the cam chain or adjuster are worn out and the chain has skipped a couple teeth.
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For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.
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One, or more, of the three necessary ingrediants for combustion are missing: fuel, compression, and a spark (at the right time).
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Please rate this answer. Thanks!

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