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.

 

[BHD]

John Deere use the 404 engine in a lot of different applications, and there were internal differences between the turbo and turbo and inter cooled and naturally aspired, some in the bearing and mounts and other internal structure

but they were taking a 90 hp naturally aspired engine and cranking with turbo and inter cooling to over 165 and have read up 200 hp, in some units

but that is a doubling of the Hp on a given set of cubic inches,

your talking about 3 hp (a cheap lawn mower in power increase), one I do not think you will hurt the engine, and two I really doubt if you will hardly notice the power increase,
about the most you will notice is the ground speed increases do to the extra RPMs,

look up in parts and see if they both use the same injectors or pump, that could be where the difference is,
on my old Rosa master pumps there is a way of adjusting the max rpm on the governor in the pump, but you need to know what your doing,

is the gear ratios the same in both tractors or is there a difference, as if you increase speed you will need more power to pull a given size implement,

(I would say while the warranty is in place I would not mess with it, as it may void the warranty when the warranty period is over, turbo that sucker and blow black smoke to your hearts content, spin the tread off the tires or what ever you want to do, but you mess with now and if some thing happens (any thing they would have cause to not warranty it.)

 

[drussell]

Once again a wealth of information available on this forum. I appreciate and thank everyone for the input. I do have a Grand L4240 HST cab model which I purchased new and now has 1900 trouble free hours on it. I purchased the B 2650 with a couple of reasons, 1. I wanted a backhoe..
2. I wanted a second smaller open station tractor to do some of the lighter duty jobs around the place. the 2650 has fit in just perfectly and taking some of the load off its bigger brother and saving some hours. I have no need to juice it up but I am curious,. as to what the possibilities might be.
As a retired veterinarian I took the oath "if you can do no good, do no harm" and I will apply it to my new B 2650, but it won't stop my curious mind investigating the possibilities. I certainly would not do anything at this time that might affect a warranty issue.
Doc Russell

 

[Texasmark]

I'd say it depends on who is tweaking the pump that day on the assembly line. Most assy. lines use color coded gauges for pass/fail criteria. If you get something in the green area out the door she goes. Green area has some margin to it so one can be on the low end of the range and another at the high.

 

[buickanddeere]

As long as the valve train doesn't float and allow the valve train pieces smack together . Or worse yet allow a valve to be impacted by a piston. Most engines can rev almost to the float point without damage.