ADVrider

Go Back   ADVrider > Bikes > Some Assembly Required
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 09-03-2013, 08:45 PM   #1
FloorPoor OP
Studly Adventurer
 
Joined: Feb 2010
Location: Spudville, Idaho
Oddometer: 710
efi F650gs engine in a KTM640e/a chassis? Has anyone done this?

Like the title says, has anyone here put an efi rotax 650 from a BMW F650GS into a KTM 640e or a chassis? I have this idea tickling my brain, and wondering if it's been done. I can't seem to search anything on this forum and get anything I'm looking for.

My silly brain is thinking that the super reliable and smooth rotax single in the much lighter and more dirtable KTM chassis would be sweeter than the buzzy grenade LC4 (which IS a sweet motor, but they don't seem to last) I love that Rotax designed engine, but Xchallenges are hard to find and expensive, the the new TR650 is way to heavy and poorly suspended. And the F650gs is WAY to heavy and poorly suspended.

Is it possible, has it been done? The final drives are on the same side, but I havn't been able to look at both bikes together to see just how it might work.
__________________
"You can have anything you want, but not everything you want."

"There's nothing like that fresh tire feeling "

FloorPoor screwed with this post 09-03-2013 at 08:57 PM
FloorPoor is offline   Reply With Quote
Old 09-04-2013, 06:58 AM   #2
Kennon
Gnarly Adventurer
 
Kennon's Avatar
 
Joined: Aug 2011
Location: Oxford, Cambridgeshire, NT Hong Kong
Oddometer: 278
never heard of this happening but all the best if you do will have to get some measurements to see if it'll fit okay, there are a ton of mods for the rotax engine especially in Germany to get some more poke out of it.
__________________
Kennon

2009 Yamaha Jog 50RR LC sold 2011
2011 Rieju Marathon Pro 125 SM sold 2013
1990 Honda VFR 400 NC30 purchased 2013
Kennon is offline   Reply With Quote
Old 09-04-2013, 09:49 AM   #3
zig06
Gnarly Adventurer
 
zig06's Avatar
 
Joined: Oct 2010
Location: Grand Rapids, Michigan
Oddometer: 120
Why?

Maybe I'm missing something but I really don't see why anyone would do this, that's why you may not have seen this done before. My reason being that changing a large thumper motor for another large thumper wouldn't really be any different than the orginal.

I personally would find a better use for the rotax. Maybe use it in a smaller (lighter) chassis, something that goes beyond what BMW had in mind. Like building an F650 that didn't break apart every time the front wheel hit something bigger than a cigarette butt.

zig06 screwed with this post 09-04-2013 at 06:38 PM
zig06 is offline   Reply With Quote
Old 09-04-2013, 10:43 AM   #4
yokesman
Gnarly Adventurer
 
Joined: Sep 2008
Oddometer: 474
do you have the engine and chassis?
see lukas , maybe he can shoot some info your way ,he has worked on other possibilities but my have the info you need.
yokesman is offline   Reply With Quote
Old 09-04-2013, 12:00 PM   #5
Kennon
Gnarly Adventurer
 
Kennon's Avatar
 
Joined: Aug 2011
Location: Oxford, Cambridgeshire, NT Hong Kong
Oddometer: 278
jammed into a 450 frame would be a good prospect
__________________
Kennon

2009 Yamaha Jog 50RR LC sold 2011
2011 Rieju Marathon Pro 125 SM sold 2013
1990 Honda VFR 400 NC30 purchased 2013
Kennon is offline   Reply With Quote
Old 09-04-2013, 06:49 PM   #6
sailah
Lampin' it
 
sailah's Avatar
 
Joined: Aug 2005
Location: Turning expensive metal into scrap
Oddometer: 5,411
Having jammed my fair share of engines into donor frames I can say that fitting the engine is the easy part. It's everything else that has you running for the booze. Airbox, exhaust, fuel all require much more consideration than just remounting an engine.

I agree Lukas is probably the most well equipped to answer this question as I believe he has extensive experience with both the bikes in question.
__________________
We're not out here to rough it. We're here to smooth it . Things are rough enough in town.

Nessmuk
sailah is offline   Reply With Quote
Old 09-04-2013, 07:11 PM   #7
FloorPoor OP
Studly Adventurer
 
Joined: Feb 2010
Location: Spudville, Idaho
Oddometer: 710
Quote:
Originally Posted by zig06 View Post
Maybe I'm missing something but I really don't see why anyone would do this, that's why you may not have seen this done before. My reason being that changing a large thumper motor for another large thumper wouldn't really be any different than the orginal.

I personally would find a better use for the rotax. Maybe use it in a smaller (lighter) chassis, something that goes beyond what BMW had in mind. Like building an F650 that didn't break apart every time the front wheel hit something bigger than a cigarette butt.
To build a better 1 lung dual sport travel bike. I love the 640A chassis, it's light enough for what I want, has a large fuel capacity, and is well suspended. But the engine, while it has plenty of punch, is buzzy at speed, gets 40 mpg, and I have not seen very many high mileage examples. They seem to grenade around 30k miles or so. Some have gone further, but many don't even make it that far.

The efi Rotax 650 single, on the other hand, has similar power output, but better bottom end, is very smooth (for a single), gets upwards of 70 mpg, and they run and run and run. I've seen more than one of those engines with over 100k miles on them. But the chassis they put them in is 100lbs heavier then a KLR, and the suspension is just as crappy. They make an excellent commuter and highway bike, but are not so good in the dirt.

Anyway, it's just an idea I've been kicking around. Take the best features of both bikes and put them in one package. I don't have any of the parts yet, but was wondering if it would be a worth while endeavor. I have no experience welding chrome molly though, so that might be interesting.
__________________
"You can have anything you want, but not everything you want."

"There's nothing like that fresh tire feeling "
FloorPoor is offline   Reply With Quote
Old 09-05-2013, 12:58 AM   #8
DRjoe
Beastly Adventurer
 
DRjoe's Avatar
 
Joined: Sep 2007
Location: Sunshine coast qld
Oddometer: 4,928
Quote:
Originally Posted by zig06 View Post
Maybe I'm missing something but I really don't see why anyone would do this, that's why you may not have seen this done before. My reason being that changing a large thumper motor for another large thumper wouldn't really be any different than the orginal.

I personally would find a better use for the rotax. Maybe use it in a smaller (lighter) chassis, something that goes beyond what BMW had in mind. Like building an F650 that didn't break apart every time the front wheel hit something bigger than a cigarette butt.

This question should never be asked in this forum (well this section at least) because if you have to ask there's a good chance you won't understand.
DRjoe is offline   Reply With Quote
Old 09-05-2013, 05:53 AM   #9
michael1968
Studly Adventurer
 
michael1968's Avatar
 
Joined: May 2009
Location: Newcastle, Australia
Oddometer: 698
Quote:
Originally Posted by FloorPoor View Post
Is it possible, has it been done? The final drives are on the same side, but I havn't been able to look at both bikes together to see just how it might work.
No, it won't work without huge mods to the 640 frame. The FI rotax engines have a downdraft inlet port, eg the port points almost straight up out of the of the head. The throttle body would need to be right in the middle of the 640's frame backbone would be.

An earlier non-FI rotax engine might fit, they have a more conventional port arrangement (straight out the back of the head).

BMW went from a backbone type frame to a twin spar frame in the F650's when they went to the new engine with FI. The new Husky also has the downdraft port, it's better for flow being a straighter path into the combustion chamber.

Just go crazy on an F650 like I did (this thread needed a pic);
michael1968 is offline   Reply With Quote
Old 09-05-2013, 09:30 AM   #10
pennswoodsed
lizards,bugs and me
 
pennswoodsed's Avatar
 
Joined: Jan 2007
Location: Reading,Pa
Oddometer: 678
rotax ktm

There were 2 rotax ktm models 504 mx and gs 1983-84 .
Regards,Ed
pennswoodsed is offline   Reply With Quote
Old 09-05-2013, 09:39 AM   #11
zig06
Gnarly Adventurer
 
zig06's Avatar
 
Joined: Oct 2010
Location: Grand Rapids, Michigan
Oddometer: 120
Quote:
Originally Posted by DRjoe View Post
This question should never be asked in this forum (well this section at least) because if you have to ask there's a good chance you won't understand.
Maybe I don't get this one, then again someone turned a sportster into an ADV bike and I didn't get that one either. Although I totally respect what he did and ended up with. And considering that it's something that you could never buy it made it that much more impressive.

In this case replacing a large single thumper with a large single thumper seems ... well... like a dog chasing his tail. But hey, I've suscribed so let me just sit back and see what happens, I may end up learning something!
zig06 is offline   Reply With Quote
Old 09-05-2013, 12:25 PM   #12
Krasniewski
I don't ride much.
 
Krasniewski's Avatar
 
Joined: Feb 2008
Location: LA - Lower Alabama
Oddometer: 1,143
Quote:
Originally Posted by sailah View Post
I can say that fitting the engine is the easy part. It's everything else that has you running for the booze. Airbox, exhaust, fuel all require much more consideration than just remounting an engine.

Concur. Strongly.




Quote:
This question (WHY?) should never be asked in this forum (well this section at least) because if you have to ask there's a good chance you won't understand.
Also agreed. I almost lost my shit on another forum with that kind of talk. Plus, seems like the OP listed plenty of good reasons to me. Longevity is a big deal. No sense taking out your favorite bike if you don't trust her to get you home anymore.




Quote:
No, it won't work without huge mods to the 640 frame. The FI rotax engines have a downdraft inlet port, eg the port points almost straight up out of the of the head. The throttle body would need to be right in the middle of the 640's frame backbone would be.
Turn the spine into an airbox?
Krasniewski is offline   Reply With Quote
Old 09-05-2013, 05:08 PM   #13
yokesman
Gnarly Adventurer
 
Joined: Sep 2008
Oddometer: 474
ala twin spline, nice thing about that is you can then build it around the eccentials,will have to go with a different tank(small considering the rest of the project), just fab a jig to hold the frame geometry in place BEFORE you cut .maybe use all the fuel system for that engine and build around it using the beemer factory frame dimensions(tube dia-thickness etc) as a guide.
yokesman is offline   Reply With Quote
Old 09-05-2013, 05:41 PM   #14
Dan Alexander
Ride Far - Ride Fast
 
Dan Alexander's Avatar
 
Joined: Nov 2003
Location: Now only Montreal
Oddometer: 6,796
__________________
Beemers Past and Present: 74 R90S, 77 R100RS, 85 K100RS, 2x 87 K100RS, 96 R1100GS (getting hacked), 99 R1100S, 2002 R1150GS, 2005 F650 Dakar
Plus the occasional Triumph, BSA, Yamaha, Honda, Suzuki and KTM but who's counting
Dan Alexander is offline   Reply With Quote
Old 09-05-2013, 05:56 PM   #15
FloorPoor OP
Studly Adventurer
 
Joined: Feb 2010
Location: Spudville, Idaho
Oddometer: 710
Quote:
Originally Posted by michael1968 View Post
No, it won't work without huge mods to the 640 frame. The FI rotax engines have a downdraft inlet port, eg the port points almost straight up out of the of the head. The throttle body would need to be right in the middle of the 640's frame backbone would be.

An earlier non-FI rotax engine might fit, they have a more conventional port arrangement (straight out the back of the head).

BMW went from a backbone type frame to a twin spar frame in the F650's when they went to the new engine with FI. The new Husky also has the downdraft port, it's better for flow being a straighter path into the combustion chamber.

Just go crazy on an F650 like I did (this thread needed a pic);
Looks sweet, but how much does it weigh? How's the handling at high speed in the desert AND at low speed in the rocks? I've thought about doing this too.
__________________
"You can have anything you want, but not everything you want."

"There's nothing like that fresh tire feeling "
FloorPoor is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 01:11 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014