How do i tuned motorcycle engine? (F650GS)
Posted: Tue Aug 31, 2021 7:47 pm
Hello. I have some 1-cylinder 650cm3 motorcycle engine, i want to enhance.
But i dont know how and what to do. Only superficial and divided knowledges.
THE SUBJECT
F650GS Dakar (2002 year).
It is well known Rotax 650 engine. Specs:
43Hp on wheel, ~= 9 transmission losses.
It has EFI from the box, known as BMS-I.
O2 + CPS. Without any phase and load sensing.
CPS is very rude (it only mine thougt). It has 5 or 6 cogs. One long and other short.
It is dirt touring (aka adventure) bike, with rally heritarge. (just model number and engine's basis lol)
I have very long story, why i want to tune this model. Shortly: it is most balanced (include buy and support cost) choice for the my targets. So please lets do not discuss that, i have many debates and no better ways were offered.
The true gold is F650RR. I don't want to get something similar, but i will give references to it.
It build with heavy tuned rotax 650 and has output with 75Hp .
All i know (from current owner of one) is what:
- It has factory team firmware but EFI is compatiable and same. (Still under NDA).
- It is bored to 700cc.
- It has very larger airbox.
- It has two pipes exhaust instead of single in civilian version.
- It has different camshaft and maybe vavles.
And the key one:
- The civilian version with factory team firmware can get 58Hp (NOT CONFIRMED).
THE PROBLEM
- It wants half or full throttle to rip wheel traction off on the dirt, on the first and second gear. (max moment revs is desirable).
On the third gear and higher it practically impossiable.
As in idle revs too.
- Revving-up from idle to max moment revs is really slow and stupid. REALLY SLOW.
You may open full throttle for two-three cycles and get only 500-1000 on neutral gear.
It sounds like engine wants to stall.
The bike is very deforced (my and some people in community thoughts).
It has two civilians firmware "The Old" and "The New". The old is sensitively better.
After the BMW has occured with EURO restriction, "The New" firmware was added.
I have both, but want >a little< (really i dont want racing monster with 100 hours before rebuild).
THE IMPORTANT INFORMATION
As i know, people tried to do something with stock EFI.
They added "power commander", zero filter, extend input air channel (no vavles and cams) and modifyed exhaust.
And have pretty zero result. Noisly 1-5Hp on dyno and some increasing of the throttle response, with any measurements.
I never heared about stock firmware tuning. Seems it never been disassembled. Im have tried too (for the joke) but have no luck due the very simple HC16 disassembler i have (IDA pro).
And zero skills in that of course.
This engine has two sparks head. And i have read some reports that it has some little better lower revs.
THE TARGETS DEFINITION
So, i want to have speed-up revving-up (with load) from lower to mid revs. Not higher. I dont have much care about it.
And have as much moment on it, as i can.
But maybe.. not too much but some little more.
So as i understand, my target is moment on lower revs and throttle response.
Ok. But i have no any thoughts about what to do. What to do first?
My current plan is:
- Add the rusefi.
- Replace air fitler to foam and extend channel.
- Remove catalytic converter from the exhaust.
- Add detailed cranksensor wheel.
- Add phase sensor.
- Setup rusefi.
- Check the goal.
If not reached.
- Add straight-through exhaust (really dont want do this).
- Add two sparks head.
- Setup rusefi.
- Check the goal.
If not reached.
- Replace camshaft.
- Replace vavles.
- Setup rusefi.
- Check the goal.
If not reached.
- Go shoot my self. (really dont want do this).
- Go bore. (dont want do this much more).
- Ask The God for lighter CPG and flywheel. (i have made to many sins for that)
THE QUESTIONS
- If you have experience, i want any of your thought and advice, you can give.
- Does plan steps is correct?
But i dont know how and what to do. Only superficial and divided knowledges.
THE SUBJECT
F650GS Dakar (2002 year).
It is well known Rotax 650 engine. Specs:
43Hp on wheel, ~= 9 transmission losses.
It has EFI from the box, known as BMS-I.
O2 + CPS. Without any phase and load sensing.
CPS is very rude (it only mine thougt). It has 5 or 6 cogs. One long and other short.
It is dirt touring (aka adventure) bike, with rally heritarge. (just model number and engine's basis lol)
I have very long story, why i want to tune this model. Shortly: it is most balanced (include buy and support cost) choice for the my targets. So please lets do not discuss that, i have many debates and no better ways were offered.
The true gold is F650RR. I don't want to get something similar, but i will give references to it.
It build with heavy tuned rotax 650 and has output with 75Hp .
All i know (from current owner of one) is what:
- It has factory team firmware but EFI is compatiable and same. (Still under NDA).
- It is bored to 700cc.
- It has very larger airbox.
- It has two pipes exhaust instead of single in civilian version.
- It has different camshaft and maybe vavles.
And the key one:
- The civilian version with factory team firmware can get 58Hp (NOT CONFIRMED).
THE PROBLEM
- It wants half or full throttle to rip wheel traction off on the dirt, on the first and second gear. (max moment revs is desirable).
On the third gear and higher it practically impossiable.
As in idle revs too.
- Revving-up from idle to max moment revs is really slow and stupid. REALLY SLOW.
You may open full throttle for two-three cycles and get only 500-1000 on neutral gear.
It sounds like engine wants to stall.
The bike is very deforced (my and some people in community thoughts).
It has two civilians firmware "The Old" and "The New". The old is sensitively better.
After the BMW has occured with EURO restriction, "The New" firmware was added.
I have both, but want >a little< (really i dont want racing monster with 100 hours before rebuild).
THE IMPORTANT INFORMATION
As i know, people tried to do something with stock EFI.
They added "power commander", zero filter, extend input air channel (no vavles and cams) and modifyed exhaust.
And have pretty zero result. Noisly 1-5Hp on dyno and some increasing of the throttle response, with any measurements.
I never heared about stock firmware tuning. Seems it never been disassembled. Im have tried too (for the joke) but have no luck due the very simple HC16 disassembler i have (IDA pro).
And zero skills in that of course.
This engine has two sparks head. And i have read some reports that it has some little better lower revs.
THE TARGETS DEFINITION
So, i want to have speed-up revving-up (with load) from lower to mid revs. Not higher. I dont have much care about it.
And have as much moment on it, as i can.
But maybe.. not too much but some little more.
So as i understand, my target is moment on lower revs and throttle response.
Ok. But i have no any thoughts about what to do. What to do first?
My current plan is:
- Add the rusefi.
- Replace air fitler to foam and extend channel.
- Remove catalytic converter from the exhaust.
- Add detailed cranksensor wheel.
- Add phase sensor.
- Setup rusefi.
- Check the goal.
If not reached.
- Add straight-through exhaust (really dont want do this).
- Add two sparks head.
- Setup rusefi.
- Check the goal.
If not reached.
- Replace camshaft.
- Replace vavles.
- Setup rusefi.
- Check the goal.
If not reached.
- Go shoot my self. (really dont want do this).
- Go bore. (dont want do this much more).
- Ask The God for lighter CPG and flywheel. (i have made to many sins for that)
THE QUESTIONS
- If you have experience, i want any of your thought and advice, you can give.
- Does plan steps is correct?