Max RPM's

[morfman]

My B2650 with the throttle wide open will only do 2700 RPM's. It's got 30 hours on it.....Is that normal? My last tractor was a BX25D and you could adjust that to 3000+ RPM's.

 

[drussell]

My B2650 has about the same hours and I have found the same thing , around 2700 rpm wide open. I have compared theB2650 to the discontinued B2920. they both use the same Kubota D1305 engine, same bore ,stroke and displacement. I suspect if the B 2650 was turned up to 2800 rpm it would produce 29 horsepower
as does the 2920 @ 2800rpm. I will be checking with my service manager who is a good guy and see if it is feasible. I suspect he will suggest we don't change anything until the warranty is up.
Doc Russell

 

[Poopdeck Pappy]

What does your owner's manual say?

 

[Fawken]

Tractors do most of their work via torque. At what RPM does your PTO hit 540? The governor may be set a bit low, but I'd rather have it a little low than too high. That's just my preference though.

 

[oosik]

2X - Pappy. The owners manual is always a good starting point.

 

[BHD]

Max RPM is just before the rods come out of the side of the block,

Rated RPM: 2500

TractorData.com Kubota B2650 tractor engine information

 

[drussell]

That was the point I was trying to get out in my previous post but I don't think I explained myself very well. The B2920 & B2650 appear to use the same engines , the Kubota D1305. the 2920 is rated at 29 horsepower at 2800 rpm while the 2650 is rated at 26 horsepower at 2500 rpm. I am NOT a mechanic but I was just wondering why the 2650 could not be turned up to 2800 rpm and produce 29 horsepower as does the same engine in the 2920.
It would appear to me and again I am NOT a mechanic, that the engine was just tuned down to pass the 26 horsepower requirement to avoid the tier 4 final requirements.What do others think and any comments would be appreciated?

 

[BHD]

I know that IH at one time used the same engines in the tractors and there combines and the difference was the RPM's. friend of mine took his tractor in and found out the injection pump was for a combine and since it was under warranty they took off the combine injection pump and put the tractor one on, he sure missed the higher RPMs,

my guess is it would not hurt the tractor any,

many tractors in the past were turbo added, and pumps turned up, but I would not suggest to go above 3000 rpm,

but on some you start to up the power, other things may not hold up as well, clutch, transmission. etc.,

 

[SPYDERLK]

That was the point I was trying to get out in my previous post but I don't think I explained myself very well. The B2920 & B2650 appear to use the same engines , the Kubota D1305. the 2920 is rated at 29 horsepower at 2800 rpm while the 2650 is rated at 26 horsepower at 2500 rpm. I am NOT a mechanic but I was just wondering why the 2650 could not be turned up to 2800 rpm and produce 29 horsepower as does the same engine in the 2920.
It would appear to me and again I am NOT a mechanic, that the engine was just tuned down to pass the 26 horsepower requirement to avoid the tier 4 final requirements.What do others think and any comments would be appreciated?

You are probably right about the engines being identical. However a simple change of the throttle stop will give empty rpm w/o the required maintenance of torque at the new rpm. ... So you can run the engine faster, but any appreciable load will drop it right back to 2500. -- BUT there are likely other adjustments on the injector pump that would preserve torque at the higher rpm. A very small timing advance and a little extra fuel are the key.

 

[wmonroe]

There could be some small difference even though the blocks are identical. A friend of mine builds pulling tractors and is a big IH fan and he said lots of farmers get into trouble by cranking their 986's up to match the output of a 1486 because they both share the same block and it appears they have the same engine just destined for the 986. According to him though the 1486's have some differences other than just a turbo to deal with the extra fuel and heat, he listed about four things but the only one I remember right now was oil jets on the under side of the piston. The piston can withstand a bit more heat with oil spraying on the underside. I might have some of the terminology wrong but what I'm getting at is be careful you don't damage something trying to squeeze out a couple more ponies.