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DRZ SM + K engine - NIGHTMARE

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Any help from you awesome lot would be very much appreciated.

 

I'll start from the very beginning and try to cover EVERYTHING so far:


I bought a pretty standard 2007 SM (mikuni carb etc)

 

I blew it up (yes, oil)

 

I found a 2001 (or around that year) kickstart ONLY DRZ engine (K engine, same as E but no elec start), and i put that in the bike assuming all would be good and i could carry on as normal WITH OIL and i wouldnt have problems.

 

Ive got problems.

 

The bike runs, but not very well at all.

 

BIKE LOW DOWN:

 

K&N Air filter

Remus can (came with the bike and sounds good so its staying on)

3x3

JD jet kit

Mikuni CV carb (standard SM carb)

 

 

1st question: Is it possible for the K engine to function properly and fully with the standard SM carb? (Mikuni carb)

2nd question: If not, why? And if so, why was my engine backfiring at 1/2 throttle? (sometimes even at about 1/4 throttle!)

3rd question: Can somebody PLEASE help me?

 

My plan is to fit FMF header pipe and fit FCR39

 

If that doesnt sort anything out then im gonna go MAD

 

 

Over and out.

 

 

 

 

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Hopefully just a jetting issue,... what is the situation when the bike is backfiring.....???...standing free revving, on decel ,while riding.?

Confirm what set up you what to run with this bike and we can advise you on correct jetting...

There is also a possibility of clogged jets......

If you don't want to waste time sorting the stock carb, perhaps move on now with your Fcr plans etc.

 

BTW....Do you know the use history of the donor engine.?

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Craigo is backfires in acceleration only, the revs rise cleanly from idle to about 4k and then its like riding a mechanical bull - sounds like gunfire too, rapid backfiring.

I think im going to move on with fcr because obviously that carb is better than stock.

Alls i know about the donor engine is that its an old one and its stolen/recovered

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Craigo is backfires in acceleration only, the revs rise cleanly from idle to about 4k and then its like riding a mechanical bull - sounds like gunfire too, rapid backfiring.

I think im going to move on with fcr because obviously that carb is better than stock.

Alls i know about the donor engine is that its an old one and its stolen/recovered

 

Clogged jets is sounding a good possibility 

Edited by Craigo 485sm

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Unless the clog is further up into the carb than the jet and its housing i can tell you its not that.

I'll have a look though to make sure.

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The more I think about it, that shouldn't matter. If you put an SM CDI in an E or a K, there will be problems, without modifications. However since you are just swapping the motor, it shouldn't really be the that.

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Will it rev past the backfire? If it can then the CDI is not the issue.  I wouldn't think it would be anyways, the SM and old Kicker E models probably have the same ignition mapping?

It could be your needle, you could try dropping the clip and trying again.  

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The "different" engines are totally the same, except for the cylinder base gasket and cams (E model has a thinner base gasket and more aggressive cams). The K engine doesn't have a starter motor and no place to put one. The S/SM cylinder head doesn't have an option to add manual decompression.

 

Other than that, they're functionally all the same! ;)

  • Like 1

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I know if you want to run a e-model cdi in a sm, you have to cut the green wire.

Guess it may me something the other way as well.

The k-engine has several different parts than the other models ; flywheel, stator and a couple of other parts for the engine case.

There should be no problem running this engine with a bsr , but you will loose a lot of power compared to the fcr

Edited by f2dog

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It wont rev past the backfire (or if it will i dont know it because i didnt want to damage anything) the backfiring would happen at a higher rpm as the bike warmed up.

It was almost as if it couldnt get the burnt fuel out of tge cylinder and out of the exhaust fast enough! I think that was partly due to the standard header being in place - since this i have fitted a powerbomb head and ive not yet tested to see if the problem is still there or not

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It wont rev past the backfire (or if it will i dont know it because i didnt want to damage anything) the backfiring would happen at a higher rpm as the bike warmed up.

 

 

my bike was doing this yesterday, im having a charging issue. my battery will be here tomorrow, im currently using a 7 year old stock sm battery..

it would not rev past 5k..it would cut out like crazy, like a mechanical bull as you said..then if i slowly release the the throttle, it would go back to normal..and run fine,but anything over 1/3throttle would cut out//or over 5k rpm it would cut out

Edited by 707LAKE

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Thats exactly it!! You described it perfectly!!

I think for the price of a new battery i may aswell give it a shot!

If that sorts the problem out and further down the line it happens again, ive got a charging issue too......

New battery AND stator do you think??

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After you replace the battery check with a multimeter when running should be no less than 13.9vdc, ideally around 14.2 at about 3000-4000rpm. Otherwise check AC voltage coming from stator of you have good voltage at all 3 of the yellow wires but not getting a good charge than it's the rectifier. If all is good there i would put the SM pick-up coils, stator plate and rotor on donor engine and try it again. Other possibility could be cam timing doesn't take long to confirm it's timed correctly ImageUploadedByThumper Talk1401641401.931259.jpg

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Does the kick only motor have a different flywheel and a lower output stator? If the battery is weak, could it be a lack of power being supplied ?

Edited by Radtech

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Does the kick only motor have a different flywheel and a lower output stator? If the battery is weak, could it be a lack of power being supplied ?

+ 1, and trying to run all the lights and goodies on a street legal bike

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Thats exactly it!! You described it perfectly!!

I think for the price of a new battery i may aswell give it a shot!

If that sorts the problem out and further down the line it happens again, ive got a charging issue too......

New battery AND stator do you think??

 

hmm.

well i gota battery coming tomorrow, Shorai LFX14A2-BS12 Extreme Rate Lithium Iron Powersports Battery.. a mouth full lol

and if that dont fix it..im going to double whammy it and buy a stator and regulator/rectifier about $200 for both

 

video of my issues from yesterday

Edited by 707LAKE

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