DT-85 - 1993 - TVS position and voltage

[pescadorsc]

Dea Srs. I´m writting from Brazil and first of all, excuse me by my poor english. I have a DT-85 - 1993 and I am can not exceed 3400 RPM. Already cleaned all carbs and carb repairs parts are new. One thing caught my attention. The TVS voltage is varying according to as specified in the maintenance manual: 0.455 to 0.55 V at idle and greater than 2,1V at full throttle. However the maximum voltage is already achieved with ½ the course of the throttle valve. The variation output voltage due to a part that is fixed to the axis of the second valve carburetor and there is a plastic part that rotates and displaces a plunger inside the sensor. This piston base has a magnet which influences the internal circuit of the sensor that responds to the variation of the output voltage.
My question: The engine timing should varariate linearly throughout the engine speed rage or is it sufficient that it variaate up to half throttle position?

[Solarman]

dt85, 1993, TVs on carbs

My motors are not carb'd (efi version) but my tps (different from your TVs) varies from idle through wot.
It must be adjusted properly, or the timing advance will not coincide with the throttle position, and the motor will be out of timing throughout the throttle movement. Adjust per manual, or have dealer check the TVs and adjust properly.
Best I can offer.
Good luck, let us know what happens.

[pescadorsc]

Thanks Solarman. The problem is: there is no adjust. As I said there are a fixed position for the sensor and there is a plastic part fixed in the chart carb that move around and press the sensor pin. The problem is that all curse of this pin is riches at the beginning of the movement of the carb Chaft. If someone could check if in his sensor happen the same thing I will be very happy.

[Solarman]

dt85, TVs problem

Is it possible that the plastic piece is 90°, or more out of place? If you remove the tvs, and rotate the throttle half way open, will the TVs slide back in place? And maybe then you will have TVs back in place when throttle is released? Will it read correctly then? I'm only asking cause in cleaning carbs some pieces might move, and the notches not line up right?
Give it a try, and let us know.

[pescadorsc]

Now some pictures that I took last weekend. It seems no assembling error. Some one know the rigth number of main jets. I´m using as showed in manual 1st and 3rd (170) and 2nd (180). is it correct? The air screew ajustment is around 1 lap back. I try 1.5 but the temperature rise (too lean). There are some suggestion?

[Solarman]

dt85, TVs position, carbs, 93

I looked up your parts for your carbs, it only gives one size main jet for all three carbs. Did you change one jet? Did it originally have one different jet? All three air mix screws should be adjusted the same, if too lean turn all three in the same. If the air mix screws are grooved/ worn, then replace those screws. If 1.5 turns out is too lean, then try 1.25 turns out. If still too lean set them at 1 turn out.

Your TVs is much different than mine, if there is not an adjustment, then you should be good on the setting. Check the manual, if it checks out leave alone.

Does your Suzuki monitor gauge give any flashing codes when you turn the key on? Not start just on position? Look and see.

There is also a gear counter coil that counts the teeth of the flywheel, if this breaks down at higher RPMs, then your motor will run poorly, it must be close enough to flywheel to count each tooth, set by the book.

If you are still not able to get motor running right, then inspect fuel pump, look at small clear check valves. They must be in good shape, or fuel pressure will be poor.

is the motor misfiring at higher RPMs, if you pump fuel bulb does the motor pick back up?

You also have three ignition timing/ pulse coils, and one capacitor charge coil. if one or more timing coils are breaking down at higher RPMs, they will cause that cylinder to drop out; or, if your capacitor charging coil is breaking down at higher RPMs, the motor will run poorly on all three cylinders at same time.

Let us know what you find. Good luck.

[pescadorsc]

Solarman, I had found in a "Suzuki Parts Catalogue" that the main jets up to 1994 dt-85 are 157,5 and I have on may carbs 170 for the #1 and #3 and 180 for the #2. The sparks are wet with oil, and I´m supposing that wrong mains jets could be the problem. "Extra fuel" that may justified the high fuel consumption. I will replace it to the correct number and will inform.

[Solarman]

dt85, 93, carb jets

Your right on size of main jets, if you're certain your motor is 93. It looks like they changed sizes a few times.
At $5 each, I'd try too. When you get the jets replaced post how it goes. And thnx for keeping us in the loop. Good luck.

[pescadorsc]

Find the solution

Hellow guys, I had change the main Jets to the rigth number #157 and tested last weekend and now I know what is a good engine. I run at 5,000 RPM with 4 guys insite the boat and top speed of 35 MPH. The fuel consumption reduced more than 20%. Thak you a lot for your opinions, its help me a lot.