97 DT 115 Throttle sensor how to set

[gambler2101]

I have a 97 DT 115 that is not running on the middle two cylinders as strong as the top and bottom it surges mid speed between 3000 and 4500 as well as wot. It seems like the timing is off but cranks and idles fine even runs ok just not right. I went through the carbs and they are clean fuel pump seems fine.

I would like to set and test the throttle sensor but the only book I have that shows the procedure is old and has a three wire sensor. This motor has a two wire sensor green/red black/red in the plug and a ground that comes off the body of the sensor. Does anyone have a schematic of the procedure of setting my motor? It would be really great if someone has the service manual in .pdf I could get from them with all the resistance readings for the complete ignition on this motor. Thanks

[Solarman]

I believe you have the carbs that have different size jets for each carb. If they were removed and not put back in the correct carb, your carbs won't run correctly. Also if any of the air, or fuel pas-sages have not been blown out completely, there may be trash restricting those areas. Another possibility is the check-valves in the fuel pump(s), if damaged fuel will be restricted, and not flow evenly to all carbs.
The timing is controlled by the gear count coil, pulse coils, and throttle position sensor, read by the ECU.

The last possible area of concern is compression between all cylinders. No cylinder should be more than ten percent different than any other cylinder.

You should get the proper manual for your suzuki motor. I will look at my manuals, they may show your motor.

Do not try to change any setting on the tps, it should not be adjustable on your motor, it is a fixed position sensor that is either good or bad. If your other cylinders are running fine it won't be your problem. They use one sensor for all cylinders. The black wire is a ground wire then one wire for voltage in (5v, I think), and a signal return that I believe varies 3-5 times as throttle opens.

Good luck, post back when able.

[gambler2101]

Solarman thanks for taking the time to reply. This motor has the same size jets in each carb. I also did a leak down test on all cylinders followed by compression test. All checked out fine less than 2% leak down on all cylinders and 120lbs compression on each cylinder.

I think I am going to go back through the fuel pump and carbs then try it again.

[Solarman]

I think that's where your problem is.
When checking the fuel pump, look at those small clear plastic discs (check-valves, 2 in each pump). If cracked or fragmented your pump won't work well. (These discs do not come in the rebuild kit, only in new pumps.) Also, if fragmented, often you will find the missing pieces lodged in the needle valve seat (you have to remove the seat to get the pieces).

When going through carbs again, make sure you blow through each little hole/orifice pas-sage with compressed air.
You only need to remove all the jets, float & needle valve seat, to clean these carbs. (I don't even take my TPS off anymore, if I soak carbs, I just turn tps to the top and soak everything below it.), also i never remove all the linkages, just the clip on linkage (for throttle & choke) that ties the 4 carbs together.

You must reset float level adjustment anytime needle valve seat is removed, or changed, by the book.

When putting together, the air mixture screws are all set identically, book setting, and left alone. The idle stop screw is the only thing I change if idle isn't right.

Good Luck. Post back how it's going when able.

[gambler2101]

When putting together, the air mixture screws are all set identically, book setting, and left alone. The idle stop screw is the only thing I change if idle isn't right.

Good Luck. Post back how it's going when able.

Solarman I dont have the service manual for this motor can you tell me what the book calls for on the lean rich mixture screws? I set mine at 1 1/2 but would like to know what the manual calls for. Its a dt 115 97 model. Thanks

[gambler2101]

lean rich settings dt 115 1997

Can anyone help that has a service manual? I need to know what the lean rich screws setting should be on a dt 115 1997 model. Thanks