98 Suzuki DT115 rebuild or part out??

timster

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May 22, 2010
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I just bought a Suzuki DT115 and the top cylinder has gone bad. The ECM went crazy and stopped injecting fuel to the top cylinder. The previous owner ran it for a while to get home on 3 cylinders. Well they bought a new ECM for a DT140 and put in in. It ran on the hose for like 10 minutes then burned a hole in the top of the piston. Would it be rebuildable?? I know the complete history of the motor and it hasn't given them a single problem for 10 years, It's Been a great motor. So the question is, Do you think i should try to rebuild it or just sell or part it out. Ive heard its not good to rebuild, but i dont know. Please any help would be greatly appreciated!!
Also, would it be a pain to get it apart since its 12 years old, for the corrosion??
 

Marion Moore

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Feb 6, 2005
Messages
200
Re: 98 Suzuki DT115 rebuild or part out??

If you are capable you could certainly try to rebuild it. You shoud take it apart to check the damage. You would need to do this anyway to sell parts. Dissasembly is no more tricky than any other outboard or complicated engine. Don't worry about corrosion. I would recommend a real service manual for the dissassembly.

The key to being able to rebuild will be no damage to the block. Light scratches can be bored out and cylinder can be sleaved but these all raise the price of the rebuild. Take into consideration the condition of the other components like LU, tilt motor, overall corrosion, etc.

I have many part from my blown DT115 including pistons, etc so I could help you out with reasonably priced parts.
 

timster

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May 22, 2010
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Re: 98 Suzuki DT115 rebuild or part out??

Thanks you for the input. I am definitely gonna take it apart and see how bad the damage is. The motor is in great shape except for the top cylinder. like I posted earlier, this has been a really great motor. Has anyone ever heard of the ECM dropping an injector? I don't know how a boat motor works exactly but i would assume that if the injector stopped then the cylinder probably didn't get any oil. Again, I don't know how the oil injection works on these motors either. I'm just trying to get an idea of what i'm looking at. BTW, ive heard that the DT115 and DT140 are the same motor except for the computer?? Is this true? Thanks again
 

99yam40

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Sep 7, 2008
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9,116
Re: 98 Suzuki DT115 rebuild or part out??

Probably had a plugged injector or injector went bad. Need to have them checked/cleaned if you repair motor
 

timster

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May 22, 2010
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Re: 98 Suzuki DT115 rebuild or part out??

If i decide to rebuild it I will check into that. I'm still curious to know if the oil is injected with the fuel or seperately?
 

Marion Moore

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Feb 6, 2005
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200
Re: 98 Suzuki DT115 rebuild or part out??

Oil and fuel come together in the vapor seperator. It is a box looking component on the front of the engine. Fuel/oil is then sent to the injectors through the high pressure fuel pump.

A clogged/bad injector or bad ECU could cause the fuel/oil mixture to not make it to the cylinder.
 

timster

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May 22, 2010
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Re: 98 Suzuki DT115 rebuild or part out??

Thanks, that helps alot. I guess the next step is to take the head off and see how bad the cylinder is scarred and make sure the rod and bearings are ok. It looks like each piston, rod, and crank are seperate for each cylinder, so I don't think it would have effected the other cylinders. I was looking at it yesterday and overall the motor looks great under the cowling, (it's been kept up with very well) so if I can rebuild it I am definitely gonna take that road. Plus, now I have a 140 computer to put on it. Ohh, and the ECM must have shorted out becuase the plastic is melted behind it (like a spot the size of a quarter).
 

Marion Moore

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Feb 6, 2005
Messages
200
Re: 98 Suzuki DT115 rebuild or part out??

I just sold my old DT115 ECU to a guy who had the same thing happen to him. Brown goo came oozing down the side of the ECU.

You are right about the pistons, rods, etc. Each one is separate. I have three good ones and the othe one is toast. I also have fuel injectors if you see you need some of those.
 

timster

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May 22, 2010
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Re: 98 Suzuki DT115 rebuild or part out??

Thanks, I will keep ya'll posted on the progress. I probably won't get to take it apart for a week or two. I'm dying to see what it looks like inside.
 

timster

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Joined
May 22, 2010
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37
Re: 98 Suzuki DT115 rebuild or part out??

Yesterday i got a chance to take the upper head off, and to my surprise it really doesn't look that bad. The scratches in the cylinder aren't to deep, I think some .20 over pistons will take them out. It looks like a rebuild is do-able. I took some pics, what do you guys think?

Also, has anyone ever used the wiseco piston and rings that they sell for these motors. Wiseco vs. Suzuki pistons??? We always used wiseco pistons in our motorcross bikes and loved them. Just curious, Which would you use?

Piston.jpg


cid_457.jpg


cid_15.jpg
 

timster

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May 22, 2010
Messages
37
Re: 98 Suzuki DT115 rebuild or part out??

Does anyone know what parts are different between a DT 115 and a DT 140?I know the computers are different and it looks like there might be different heads on a 140. I have a 140 computer for my 115 and I want to make sure I don't need parts like throttle body or injectors,etc to make it a 140. thanks
 

sttopr1

Cadet
Joined
Feb 21, 2010
Messages
19
Re: 98 Suzuki DT115 rebuild or part out??

I saw somewhere that they are the same motor with the exception that the 140 is bored out more, not positive though.
 
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