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Discussion Starter · #41 ·
Update on today didnt really get the engine in. All connection on throttle body are the same, so went straight in with the new air box as the old one was broken.

Found out the the starter motor is different, totally overlooked this so trying to get hold of one now before we go any further.

Lamda sense cable was to short also so had to cut into the harness and luckly the wires ran back towa5ds the front of the bike so just traced back and exited the lamda cable from the main harness clisser to the exhaust.

Still waiting on cush drive? Chesked tracking today and its apparently back in miami? Dont know wats gone on there but emailed them to find out.

Looking to finish off one evening next week, but who knows? I did take pics but they are on a mates phone so will get them emailed to me and posted up.
 

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will be interesting to see the pics.

good luck with the rest of it :)
 

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Discussion Starter · #43 ·
will be interesting to see the pics.

good luck with the rest of it :)
Not the best pics will get some better ones when we finish the bike. also ill try and take afew specific pics to show differences with lamda cable starter motor, front and rear sprockets.
 

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Will the 390 motor fit into the frame without modification? What about the radiator - The 390 engine generates significantly more calories than the 200, is the radiator the same as the 390's, or smaller?
 

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Discussion Starter · #46 ·
Will the 390 motor fit into the frame without modification? What about the radiator - The 390 engine generates significantly more calories than the 200, is the radiator the same as the 390's, or smaller?


Part numbers for the rad and pipe work are different in the KTM catalogue, but the size of the rad seems fine to me to be honest, its not that small and its not as if its being used to run a 900cc motor. All exploded diagrams seem to be looking the same and the pipework from the 125 fits the 390cc motor. But comments noted Ill keep a eye on the temp and could be a further cost in the future.;)
 

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Discussion Starter · #47 ·
Thought i would do a run down of parts changed to date.

Essential parts:
Engine and Starter motor
ECU
Throttle body
Header
Sprocket carrier and cush drive
Front and rear sprockets

Ive also been changing a few other bits as well while its apart.

Airbox (optional it is slightly different but a 125 one will work)
Chain (New vxr2 gold chain going on again optional)
Uprated cush drive (Could of gone with a cheaper standard one)
Full exhaust (unsure if 125 one would cause issues)
DNA Air Filter ( Again not really needed)

Cost wise it is now approaching cost of a secondhand Duke 390, its is still cheaper but not massively and that's with out factoring in the resale value of 125 parts, but we all knew that this wasn't going to be cost effective.
 

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Discussion Starter · #48 ·
Hi all been alittle busy but the bike is up and running with the 390 motor.


It was alittle more troublesome than I expected. Having some issues with the fuelling at the moment, it seems very hesitant in the midrange, also the rear wheels are different so got some orange ones on order, luckily the RC125 wheels are the same as the Duke 390. also the coil pack water pipes and front engine brackets were different.


But this is achievable with a day or twos work. should look nice with the orange wheels and tank cover when the come.


I am drawing a blank at the moment on the fuelling I had DNA filter in there at first and the idle was very lumpy. I Removed if for a standard filter and this has sorted it to a degree, I was wondering does anyone know if the 390 runs a bigger fuel pump to the 125, all my research is showing it to be the same?
 

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Discussion Starter · #49 ·
New parts list as to what you will require to do this conversion


Essential parts:
Engine and Starter motor
ECU
Throttle body
Header and lambda sensor
Front and rear sprockets
Water pipes
Radiator Brackets
Front Engine Brackets and bolts
Coil Park
Duke 390 or RC Rear wheel (including sprocket carrier)
Sprocket cover
Clutch cable and bracket
Airbox (if your Fussy)


I Think that's it :)
 

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Well done on your work to date. Looking down the list of what you have changed already the fuel pump seems a likely culprit (assuming all the other parts fitted are ok). A quick look at the part finder at AMS motorcycles does list the fuel pump part numbers as different between the 125 and 390.
 

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Discussion Starter · #51 ·
Cheers:)


On the rebuild kits the pumps are showing as a 30mm pump for both 390 and 125 which is why I questioned it??


I do have an after market exhaust on the bike and it is super loud so think of returning it back to standard? Would this have any affect?
 

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Exhausts can have a significant effect. If your current one is 'super loud' then that suggests little or no back pressure. The back pressure / reverse pressure waves of the stock system will aid scavenging of the spent exhaust gasses out of the engine that also aids efficient filling of the cylinder with fresh air and fuel. Of course any negative effects of some after market exhausts can be accommodated with a fuel controller, but without one your bike will most likely run better with a stock 390 exhaust (if you don't have one, there is one on eBay for £35 currently just listed as 'duke exhaust' with part number. Thought I might buy it myself as mine is nicely rusting but I suppose you need it more than me. All that said though I am not convinced the symptoms you describe are solely down to the exhaust, as other members report loud exhausts (and no fuel controller) as still running ok.
 
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Discussion Starter · #53 ·
Its defiantly hunting in mid range you can feel it. There are afew exhausts knocking around so ill pick one up an change it out. Could be another part to the list.:D
 

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Discussion Starter · #54 ·
Made abit of a discovery regards the back wheels. The later 125cc Dukes run the same cush drive set up as the 390s and also the RC125 and RC390 are the same if your duke is sub 2013 as mine is the cush drive is different and a new rear wheel is required. As mine need tyres anyway I managed to pick up a set of wheels with nearly new tyres and discs and sprockets for £225 delivered.:)
 

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Hey! Just researching about this project and got a little bit curious. How is the bike going after 5 years and a bit? And about the fueling problem - did you change the exhaust and did it help? Really interested in how it is going after this long :D
 
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