Dt65 compression

[bigman348]

Am looking at buying a 1985 dt65. Was told the motor breaks up at high rpm. The compression checks out at 95 on all 3 cyl. Is this compression ok or should it be 125? And all 3 being at 95 would it still run well?
Thanks

 

[hsdtech]

Re: Dt65 compression

Who checked the compression, you or the seller? Those readings are low. The motor breaking up at high rpms could be several things.

 

[JB]

Re: Dt65 compression

When all cylinders read close there is probably a flaw in the gauge or the technique. Three cylinders don't all go bad by the same amount at the same time.

I think your compression is okay. Breaking up at high rpm is likely to be plugs, ignition or fuel feed.

 

[bigman348]

Re: Dt65 compression

Thanks for the info. I made the guy an offer so we will see what happens.

 

[James R]

Re: Dt65 compression

A compression gage is cheap, around 15$. Be sure and do your own check. It is possible for all cylinders to be low but I agree that usually one cylinder can fail. The Thing is that the Suzuki has a common oil pump and failure of oil flow may show on all three cylinders. Normal good comps are 130 but 125 is still very good.

 

[bigman348]

Re: Dt65 compression

My current dt65 has 125 psi compression on all 3 so I will stick with it. And the gentleman selling the low compression motor wants $850 and i am not willing to pay that for a motor not in good running condition. Afraid I have an issue with crankshaft seals leaking in between cylinders. Have been though everything on motor fuel and electrical. Even went as far as to get another set of carbs to be sure and still runs well on out of water but when put in water starts and dies when given any throttle. Can get it to put along at about 4 mph if i get it just right. Was hoping to get another power head being that the one i have was used in salt water and have had issued braking bolts when i removed the head cover to removed the already broken bolt in the water sensor. Does anyone know of any way to pinpoint that the crankshaft seals are faulty without splitting the case?
Matt

 

[mphelle8vld]

Re: Dt65 compression

Doesn't sound like crank seals. Assuming that your carbs are spotless, including the three tiny holes in the top of the bore near the throttle plate, have you tested and properly adjusted the throttle position switch on the middle carb? If you're not sure, send me a PM and I'll send you the procedure.

 

[James R]

Re: Dt65 compression

You can disconnect the TPS and the motor will go to nominal setting. If the performance improves then replacing the TPS may be the answer.
TPS's have been known to fail.
Dang this is an old post.

 

[RobMarkland]

Re: Dt65 compression

Doesn't sound like crank seals. Assuming that your carbs are spotless, including the three tiny holes in the top of the bore near the throttle plate, have you tested and properly adjusted the throttle position switch on the middle carb? If you're not sure, send me a PM and I'll send you the procedure.

Hi there.

I also have a Suzuki DT 65 1985 model that I'm keen to get the procedure for the tps on the middle carb. Another question I got is my motor has a wicked cold start but once started starts every time any ideas if you can help please.