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Kenny O.
Kenny O., Motorcycle, ATV, Mules, Side by Side's Product Specialist. All Brands
Category: Motorcycle
Satisfied Customers: 953
Experience:  Worked for Kawasaki Motors as a Product Support Specialist (Factory Support) for 24 years
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1987 Suzuki: Quad..Sport..compression, spark and gas..running great

Resolved Question:

I have a 1987 Suzuki Quad Sport LT80 and it will not start. I have compression, spark and gas at the new spark plug. The quad was running great but after an afternoon of mud track fun my son told me it started to feel like it had a fouled plug. The plug was bad, so I changed it. I noticed he sucked a lot of water into the intake tubes. So I removed everything and cleaned the mud out as well as check the air filter and removed and cleaned the carb out. What would the symptoms be if the reed valve was bad? When we turn it over it wants to start but just won't get there. It does have a full charge on the battery
Submitted: 6 years ago.
Category: Motorcycle
Expert:  Kenny O. replied 6 years ago.

Hello my name is Kenny


You say that you checked compression, can you give me that number ?




Customer: replied 6 years ago.
It had enough compression that it could push my thumb off the spark plug hole, and on intake it would suck my thumb into the spark plug hole. I do not have a compression guage
Expert:  Kenny O. replied 6 years ago.

I Guarantee that you have a compression issue, you need to check that, I have NEVER seen where water and mud into a engine will survive, take the spark plug (so you get the right size gauge) and you can go to a Autozone or any of those chain Autoparts store's and you can rent one from them or if you have a Harbor Freight Tools, you can pick one up there for about $10


100 psi (which is what this unit will require to start) will blow your thumb off, but 80 psi it will not start, 20 psi with the thumb, you'll never be able to tell the difference.


I have seen this a lot on this model, they are very sensitive to low compression.


Let me know what you come up with, I have a manual on that if you need anything out of that.




Customer: replied 6 years ago.
Are you thinking there is damage to the cylinder wall? or maybe a broken ring?
Expert:  Kenny O. replied 6 years ago.

I'm sure you did something to the piston and rings, depending on how long he rode the unit will dictate what happened to the cylinder.


This unit is really easy to work on, you can at least pull the exhaust pipe off and look through the exhaust port and or just pull the head off, but if you can I would try to do a compression test, its always better to have an idea before you go into it.


If you need help with getting anything apart then let me know, you might be able to get away with replacing the piston and rings, these little bikes are more forgiving.




Customer: replied 6 years ago.

I checked the compression and it is low 62 psi, my next move is to remove the exhaust, head, and remove the cylinder. From there I'll assess the damage. Thanks

I do have one other question, I am getting the gas filling the cylinder, I have replaced the needle and seat in the float bowl and still have this problem.

Expert:  Kenny O. replied 6 years ago.

That is likely from maybe the low compression, remove the carb and put it in a vise, then hook an external fuel tank to the carb, see if it leaks, if you have to pull the float bowl off and then hold the float closed, and see if you have leaks somewhere else in the carb, you float level could be a little high, also make sure the "float" floats, drop it in some water just to make sure.


Well i think you found your problem, good lesson learned here, the old thump works sometimes but it can bite you also,


Glad you got it figured out, let me know if you need anything else.


Thanks again !


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