Combines 750 at 3 5mph i must be doin alotta wrong

How big is your head IJ What is your corn yielding and what is the moisture IJ These all make a difference. But, if you have good cylinder bars and your cyl_concave_ cyl speed are all correct and you are getting whole cobs on the walkers, you should be able to run your fan on high with the front of the top sieve open pretty wide and truck right along without throwing corn over. If you are not getting mostly whole cobs, you need to start there. I'd set the rear concave at 3_4" with the front lever in the mid range. Cyl speed around 400 RPM. The secret to making these combines work is proper threshing so that the sieves do not have to make up for overthreshing, which will overload them and make the combine seem like it has no capacity. I am currently running a gray cab 750 as a second machine and am very pleased with the job it does and its reliability. Hope all this rambling will help you.

I remember the first 750 I had. I could not go faster than what you are. Corn was just running off the walkers. The guy I bought combine from had removed the "mud flaps" from behind the beater and the corn was not hitting the walkers until it hit the metal flaps. Don't know if this is your problem but a place to start. When I set the seives and chaffer I shell off some corn and just throw it in there and if it all falls through then I know if they are open enough. Then I set them as I run for how clean the sample is. I have noticed that some of the corn has BIG kernals and the sieves need to be open more. If you are not running a round hole lower seive I suggest you get one that way you can open up the front of the front chaffer wide open and most of your corn will fall in there. I am running a modified concave that has every other wire removed in the rear 2_3rds to allow more corn to be separated right there. You would not believe how much difference it makes in wet corn. If you have a chance shut machine down under full load and take a flashlight and look at rear of concave and look to see how plugged it is. If there are a lot of cobs and shucks stuck in there they are robbing you of capacity. Hope this helps

Three things come to mind. First is that the display in many combines is actually KIlOMETERS per hour, not MPH. So 3 KPH is about 1.8 MPH, etc. Second is that it makes a lot of difference what the bushels per acre is. I've run at 8 KPH (4.8 MPH) or a little more in poor yeilding corn with a 750. Third is that they may be exaggerating. No way to know that for sure.

Not exagerating, Don't have a guage to tell me how fast we go in 1977 model 750. Just go by calc-an-acre in tractor pulling along side unloading on go. A well tuned machine running full will wear out in same hours as a 1_2 loaded machine not so well maintened, so better to keep in top shape than half-@$$ed, you will be money ahead in long run and less down time.

I've been running a grey cab 750 since 1992.We use a 9118 header and an 1163 corn head. Your post got me thinking about ground speed again. This week I was running 4.5 km in 200bu corn @ 19% Screens are wide open, but return screen is almost closed. Fan is on high, aimed towards the front. Cobs are whole. No corn going over the back. This is the first year that I think I'm getting the capacity I should out of the machine. The biggest limiting factor on the 750 is power once the bin is almost full.