What's the difference between 700 & 800 engines?

[woopwoop]

What's the difference between the engine in the F700GS and the F800GS? I was told recently that the only difference is the "chip". Is that correct?

[GH41]

It is probably more than the map. Some will argue but the performance difference is very small. GH

[Kiwi Tinkerer]

I looked up the parts fiche (Max Motorcycles)
The engine control units are identical. (Same part number)
The difference is in the engine itself and the map loaded on the control unit.

Some of the parts that are the same:
Valves
pistons

Some of the parts that are not the same part number:
Cam shafts
engine
throttle bodies

So, perhaps change the throttle bodies and cam shafts would help.
However, the control unit may be keyed to 650/700 and only load that map.

[ebrabaek]

Interesting about the Throttle body's. I knew that cams were diff...... I would suspect that the preforming part of the Throttle body's are the same... perhaps just cosmetic....

[LukasM]

Kiwi has it right, throttle bodies and cams are different, and the map that's loaded in the ECU. Everything else is the same, so upgrading to the same HP won't be difficult once somebody figures out how to crack the ECU. A German company has done it but I haven't been able to reach them. I also think that you will be able to get most of the power with an aftermarket fuel controller, probably even more than a stock F800GS because those run pretty lean. Ignition timing won't make as much of a difference.

I've got both F800GS and F650GS throttle bodies here, will have to see what the difference really is when I find some time in the shop.

[ebrabaek]

Originally Posted by LukasM

Kiwi has it right, throttle bodies and cams are different, and the map that's loaded in the ECU. Everything else is the same, so upgrading to the same HP won't be difficult once somebody figures out how to crack the ECU. A German company has done it but I haven't been able to reach them. I also think that you will be able to get most of the power with an aftermarket fuel controller, probably even more than a stock F800GS because those run pretty lean. Ignition timing won't make as much of a difference.

I've got both F800GS and F650GS throttle bodies here, will have to see what the difference really is when I find some time in the shop.

I for one is interested in that.......

[woopwoop]

Originally Posted by Kiwi Tinkerer

I looked up the parts fiche (Max Motorcycles)
The engine control units are identical. (Same part number)
The difference is in the engine itself and the map loaded on the control unit.

Some of the parts that are the same:
Valves
pistons

Some of the parts that are not the same part number:
Cam shafts
engine
throttle bodies

So, perhaps change the throttle bodies and cam shafts would help.
However, the control unit may be keyed to 650/700 and only load that map.

Originally Posted by LukasM

Kiwi has it right, throttle bodies and cams are different, and the map that's loaded in the ECU. Everything else is the same, so upgrading to the same HP won't be difficult once somebody figures out how to crack the ECU. A German company has done it but I haven't been able to reach them. I also think that you will be able to get most of the power with an aftermarket fuel controller, probably even more than a stock F800GS because those run pretty lean. Ignition timing won't make as much of a difference.

I've got both F800GS and F650GS throttle bodies here, will have to see what the difference really is when I find some time in the shop.

Thanks gents. A friend and prospective F700GS buyer was told the other (IE "chip only") by a salesman. I'm no expert but it didn't sound right...... The same salesman also told my mate the F700GS puts out 90 horsepower!

[JRWooden]

Originally Posted by woopwoop

Thanks gents. A friend and prospective F700GS buyer was told the other (IE "chip only") by a salesman. I'm no expert but it didn't sound right...... The same salesman also told my mate the F700GS puts out 90 horsepower!

Interestingly the F800GT does crank out 90HP so there is yet another bits-and-pieces-ECU map set variation...

[pkbinder]

Some things I know and some things I have only heard. My engine is the "de-tuned" 71hp engine. I have heard the the 85hp engine only generates 74hp at the wheel. I have no idea what my engine generated at the wheel before I did my modifications (Remus headers, Akropovic exhaust and PC-V controller), but the dyno tells me that now I get 74hp at the wheel. pk

[JRWooden]

Comparing the F658GS to the F800GS

The F658GS has less lift on the cams,
more conservative ignition timing (and burns regular gas),
does not need the "secondary air" system that is provisioned into the valve cover but unused on the F658GS
there may be other things also ....

A nice table of the F650GS / F700GS / F800GS / F800GT would be nice reading material .......

[GH41]

Originally Posted by pkbinder

Some things I know and some things I have only heard. My engine is the "de-tuned" 71hp engine. I have heard the the 85hp engine only generates 74hp at the wheel. I have no idea what my engine generated at the wheel before I did my modifications (Remus headers, Akropovic exhaust and PC-V controller), but the dyno tells me that now I get 74hp at the wheel. pk

Did you gear the 658 like the 800? If not there may be a little to gain at the wheel. 14 HP sounds like a lot for pipes and a PC. $100 per HP is cheap power! Almost to good to be true. GH

[LukasM]

Originally Posted by pkbinder

Some things I know and some things I have only heard. My engine is the "de-tuned" 71hp engine. I have heard the the 85hp engine only generates 74hp at the wheel. I have no idea what my engine generated at the wheel before I did my modifications (Remus headers, Akropovic exhaust and PC-V controller), but the dyno tells me that now I get 74hp at the wheel. pk

74 at the wheel is good! Of course it totally depends on the dyno and the parameters the operator used. Was it a Dynojet or another brand?

Originally Posted by GH41

Did you gear the 658 like the 800? If not there may be a little to gain at the wheel. 14 HP sounds like a lot for pipes and a PC. $100 per HP is cheap power! Almost to good to be true. GH

Are you saying that gearing influences power?

[grandru]

The radiator is also smaller.

regards

[itsatdm]

Originally Posted by LukasM

Kiwi has it right, throttle bodies and cams are different, and the map that's loaded in the ECU. Everything else is the same, so upgrading to the same HP won't be difficult once somebody figures out how to crack the ECU. A German company has done it but I haven't been able to reach them. I also think that you will be able to get most of the power with an aftermarket fuel controller, probably even more than a stock F800GS because those run pretty lean. Ignition timing won't make as much of a difference.

I've got both F800GS and F650GS throttle bodies here, will have to see what the difference really is when I find some time in the shop.

That reminds me, what happened to the poster who stuck the F800 cams into his 650? The last post sounded like a call for help.

I do agree you can get more power by running a richer mixture and a fuel controller can do that. No free lunch, you will burn more gas.

All 3 versions have the same 12:1 compression ration, so ignition timing, duration of the cams and and overlap between intake and exhaust determine the difference between absolute power and an exploded engine.

I do not understand the quest for power. All versions give more than you need for dirt and just how fast do you need to go?