engine swap

Diploman

New Member
Re the OP's question about putting a 690 engine in a 390 frame: It is already a major contortion to cram a 390 engine into a frame designed to accommodate a 125. This acrobatic feat results in an extremely "dense-pack" architecture, and an engine that is very hard to service due to the very constrained access. Trying to shoehorn a 690 engine into this frame would be pushing the envelope too far, IMO. I believe the dimensions of the 690 would be too tall in any case.
 

Diploman

New Member
Motorrad had a long article several months ago about the coming Duke 800. They said KTM chose a parallel twin because that configuration was lighter, more compact and less expensive to manufacture than a v-twin.
 

psych0hans

Member
Country flag
I wonder if a 450 MX engine can be made to fit the RC/Duke? I have a duke frame lying about and am just shy of a triple tree to get a rolling chassis together.
 
About engine swap, a long time ago, I wanted to make a racer, based on single 4 stroke engine.
I bought an Aprilia 250 RS frame, and started to adapt a Suzuki DR750 engine prepared... I've not been until the end of the projet but I still have the frame and engine waiting for me.
Lately I took the easyway to buy the RC390 ... But I keep this project in mind.
Unfortunately, the DR750 is a heavy engine, but the KTM 640 LC4 had the chain on the wrong side so it was not an option.
Now I'm dreaming of installing 690 LC4 instead of the DR750 ... and then replace the RC390 with this proto bike.
Picture of the (old) project still available here
 

OldVet

New Member
I like my little ole 390 just the way it is and part of the fun is ringing the neck on that little single cylinder... If you want to go BIG KTM has an answer for that to. Talk about something fun to ride this is it... ;)

Duke.jpg
 

todayis1984

New Member
Wouldn't it be easiest to just buy a Husqvarna 701 vitpilen And swap on the RC390 fairings, wouldn't it not BE a RC690 in every sense at that point ?
 

Old3

Member
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Slight change of OPs goals but fits the title,

are the 2017-18-19 engines a direct bolt in to the 2015/16 bikes? Besides throttle body being wireless, will the actual block bolt in and accept the 15/16 intake/exhaust?

Thanks
 

Tom

New Member
Though I've never swapped a motor between the generations of bikes, I can tell you the ECU is different. I would assume the wiring harness is different as well. the exhaust shouldn't be a problem as long as you have the header pipe for the generation exhaust you wish to use.
 

Old3

Member
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Thanks Tom, I’d want to use the older gen accessories so ECU not a problem. Somebody must have done it with all the engine shuffles on these bikes. Lol.

I guess the newer head are a direct bolt in to older bikes so the old intake must bolt on?
 

Marie

New Member
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Hi i have a ktm390rc 2014 and i need to replace the engine i have found one off a 390rc 2017 will the 2017 engine fit mine?
 

Treachery

Moderator
Country flag
I am by no means an expert, but I suspect the answer is yes. If you expand "fit" to include having all the electronics plug directly into the 2014's wiring, the answer gets a little more murky.
 

kostean

Member
Country flag
Digging up this old topics, but did not quite get a definite confirmation from an earlier thread if a newer year (2018) engine could be placed to 2015 390 if maintaining the old type throttle body?

I understand from other connectors point of view (except gear indicator) all plugs in the same?
 
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