650 conversion to 800

scoobert

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playing with the "I need more power" issue.
what would happen if i changed the 650 ECU for the one from the 800?
the acceleration on my bike is not smoothe, feel like it has a choppy powerband?
is it just holding back?
shouldnt the power be gently increasing thru the entire range?
thanks.
 
Im not sure if just swapping over the ECU will work, I think there is a few minor differences in the engines, however I maybe wrong! I'm sure some one else will correct me in a bit!
 
solution

We had the same "problem" ( 2 650ties), uneven tickover at cold start, and easy to stall when riding off. Warm much better. But after fitting Accellerator Modules and Iridium plugs a whole different behavior, a happy and regular hum after starting, and good engine pickup riding away. It improved even more after installing K&N air filters. You just feel that the machine can breathe freely now. It feels as the very good rotax engine finally reaches the potential it was supposed to have. Also less vibration, and it just keeps pulling and pulling without any effort. Another big advantage is that now you can ride with lower revs, nice if you roll through a small town and want to look around, it runs smoothly till 1500r/m, and pulls away from there without protesting. I had it on the dyno after that and it reached 205 kms/h.
I even out-accelerate my friend now, who rides a 1200, and he hates it!!
So, don't take my word for it, try it out yourself! Big improvement with little money. greets, hans
 
You can't do it. Besides the camshaft there are other changes.
These things aren't really broken in until around 20,000kms.
If you have the room on the highway, do a few runs over the course of a week and hold it WFO in 6th until it can't go any further. You might see it gain a few KMH over the course of the week. Really hammer it and don't shift until 7k on each run through each gear and hang on for the wonderful 3rd to 4th upshift above 7k that quickly becomes very addictive. Smiles all around, and frowns and finger waving from frumps.
Take a look at the power curves of the two bikes, and you will see that unless you are riding all the time at over 7,000rpm, you've got almost the same stuff on tap. Play with your gearing if you want a faster getaway. Be realistic, how many times will you get on a highway where you can actually pin the thing and give it that much stick?
If all that fails, there is always a diet plan. LOL!
 
cam shafts

The cam shafts are different profiles so you can't use an 800 ECU on an 658. The 'same' engine is use on the 800S/ST, 800GS, 658GS and all have different cam shafts.
The 800gs cam is shaped to make it sound like an horizontal offset twin, the 1200gs.
Just use a power commander for an 658. If i remember correctly the engine in both 800 and 658 format are starved of air in the mid range to achieve emission control regulations. That is why I get this lovely pop on the over run. Fit a power commander the air/fuel mixture will be adjusted and the mid range will gain a lot more torque/power.
They should pay me for this.
To geek this even more on an 800gs the open degree of the inlet valve is 14 or 16. The closing in 16 or 14 degrees. I think
 
Not only the cams are different, but there are a few other internal changes.
I think you mean that the motor is starved for fuel and not starved for air.
It is a lean run condition, I believe, and you change the fueling map to gain a richer (ie more fuel not more air) mixture.
 
wat i know is the F658 is missing Item Call *(SLS)which control the air n fuel mixture item which all F800GS or F800S/ST. tats opinion.

6776942759_fd0e6aca27_z.jpg


6815260473_d3a0b75d84_z.jpg
 
Shadwell said:
"Dean"s looks very similar to an 800. Im surprised he hasnt anything to say on the matter:)
Click to expand...

Shad only the rear wheel is standard fit F800GS the rest is Pure F650GS :augie :D :D

As for the "playing with more power issue" I feel I have enough as standard and would not want to tip the balance of power, gearing, fueling that I already have, maybe a small tweak from the decated pipes, Akro can and K&N air filter :D

Personally allways thought the bike was smooth in all areas depending on the wrist action and the gear i,m in if its not then its my rider error's tick over is and allways has been OK :thumb

:beerjug:
 
K&N?

Hi, Dean, a warning: your minor tweaks will make an already lean mixture even leaner. The K&N filter is MUCH more open and has a lot less resistance to the inflowing air. An Akro can will make matters worse. Remedy: the accellerator module that enriches the mixture enough to compensate that. Worked for me. Plus you get a better ride. See my above post. All the best, hans
 
Are you sure the O2 sniffer won't compensate for the K and N and the exhaust can? The computer will then adjust the mixture to the optimum of the map it has installed in it, no? Those "resistor tuning" accelerator module deals give a false and different intake air temp from the real ambient temp in order to richen things.
I know that the F650 twin will run without an air filter. Mine was one of the ones that was subject to a BMW "campaign" aka "recall" because of the poor quality air filter from the factory that ripped on the lip and collapsed into the air box and was doing nothing. Bike started and ran normally for the few kms it was subject to in this condition. I have also seen and heard an S model running an open header that had suffered no ill effects, it was obnoxiously loud but ran fine.
Maybe someone can set me straight on the function of the O2 sensor in the header? I'm curious to learn more, especially if I am thinking the wrong way! LOL!
 
I can't find the link you are mentioning.
In fact, I can't find your signature. Do I have to be a premium paid member to see it?
 
Ok, I get it! Thanks, so then the use of a resistor should be obligatory, right?
The secret is to leave the O2 sensor to do its limited range thing at idle but use a resistor or resistor combination to create the fake drop in intake air temp for other throttle positions.
Correct?
Just like setting the curb idle with the pilot jet and then tuning the rest of the throttle range by needle taper, throttle cutaway, needle height, main jet size, etc... back in the day, no?
 
MikeMike said:
Ok, I get it! Thanks, so then the use of a resistor should be obligatory, right?
The secret is to leave the O2 sensor to do its limited range thing at idle but use a resistor or resistor combination to create the fake drop in intake air temp for other throttle positions.
Correct?
Just like setting the curb idle with the pilot jet and then tuning the rest of the throttle range by needle taper, throttle cutaway, needle height, main jet size, etc... back in the day, no?
Click to expand...

Perhaps, except that I'm not sure of the relationship between these resistor gadgets and the O2 sensors. At best, accelerator modules or whatever, are a quick and dirty fix. The best solution is either a Power Commander or similar device or a remap of the ECU...(see the Hilltop Motorcycles threads.)
 
Isn't the Power Commander just a more detailed form of resistor tuning with turning the pots to create a remap in the device that is then fooling the onboard computer into accommodating a cooler air temp and thus you have smoother running and richer mixture?
The power controller things usually are limited to one or two fake temps from the resistor or resistors.
 
MikeMike said:
Isn't the Power Commander just a more detailed form of resistor tuning with turning the pots to create a remap in the device that is then fooling the onboard computer into accommodating a cooler air temp and thus you have smoother running and richer mixture?
The power controller things usually are limited to one or two fake temps from the resistor or resistors.
Click to expand...

That sounds like it harks back to the days of what was it Dynojet called it -"sensor offset technology" or somesuch? Certainly from PCIII onwards, it was a matter of installing maps which adjusted the fuel and sometimes ignition maps in the bike's ECU. Power Commander V has taken that a step further with the Autotune module which is a wideband lambda sensor (or two if you fit the Harley kit) which allows you to remap the bike on the fly and enables you to update the mapping each time that you make a change to the engine's intake or exhaust system or even if you port the heads, fit hotter cams etc....
 
curiousexplorer said:
Hi, Dean, a warning: your minor tweaks will make an already lean mixture even leaner. The K&N filter is MUCH more open and has a lot less resistance to the inflowing air. An Akro can will make matters worse. Remedy: the accellerator module that enriches the mixture enough to compensate that. Worked for me. Plus you get a better ride. See my above post. All the best, hans
Click to expand...

Thanks for that Hans :thumb thats interesting and little money :beerjug:
 
curiousexplorer said:
Hi, Dean, a warning: your minor tweaks will make an already lean mixture even leaner. The K&N filter is MUCH more open and has a lot less resistance to the inflowing air. An Akro can will make matters worse. Remedy: the accellerator module that enriches the mixture enough to compensate that. Worked for me. Plus you get a better ride. See my above post. All the best, hans
Click to expand...

+1 for the accelerator module
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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