Keihin FCR39 in a DRZ | GTAMotorcycle.com

Keihin FCR39 in a DRZ

Motorcycle Mike

Motorcycle Mike

Well-known member
I'm looking to replace the stock carb on my DRZ with a FCR39 pumper carb as the story is this mod makes for a great improvement in power delivery.

The issue is, this carb in a kit from thumpertalk or procycle is damn pricey ($700 to $900USD)... more than I am willing to spend.

A guy I ride with sometimes has one for sale, but I am not certain if it is what I need as apparently there are variations of the FCR39?

If any of you have experience in this matter and can shed some light on whether this is the right carb for the job, I'd appreciate it:

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I had this conversation yesterday, since im all gung ho on DZ this week.
Supposidly the FCR39 is the right carb, but there are different adapters for S,SM, and the other models of bike. And 5 or 6 jetting kits depending on which pipe you have on your bike and height above sea level.

so I guess if you buy one from a guy you ride with that has the same setup, ok, otherwise you might be looking at a $50-70 dollar jetting kit to make it work best on your bike. I'm told you can get a carb spec'd to your bike for $500 US, thats a lot of cabbage unless its awesome.
 
I dont have experience with your specific application, but I did a FCR28 downdraft pumper conversion on my CRF50 many years ago. My kit cost around $800, but included the correct, cables, manifold and jetting for my 124cc bore kit. Basically a bolt on with a little tuning...There were many versions and even different mounting applications instead of downdraft. If your willing to put in the work and research to find something cheaper or used that isnt a kit then all power to you..Just be aware FCR's are not easy to jet! I know mine has a ton of options for jets. So depending on how close the carb you get is to what you need for your motor, you may or may not have a lot of work to do to get it to fit and run properly.

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I run mine with no filter just a velocity stack, and there is nothing like the sound of the pumper squirting fuel. It got a nice whistle to it
 
Thanks Johnny,

I think I am going to give up this idea... I had three different people send me pictures of three different versions of FCR39s... no idea which one would work and which wouldn't... then all the extras needed for the conversion -- adaptor, manifold, throttle, jets, etc etc... and it is too much hassle.

Thumper Talk has a kit for $799USD... but honestly, my bike is worth maybe $3000 right now... to put a $1000+ carb on that seems like a waste. If I need the better performance that badly I will just sell the DRZ and buy something like a KTM which will give me a better carb (or most likely EFI), better brakes, better suspension, lighter weight, etc, etc... much more value for the money, I think.
 
Motorcycle Mike said:
Thanks Johnny,

I think I am going to give up this idea... I had three different people send me pictures of three different versions of FCR39s... no idea which one would work and which wouldn't... then all the extras needed for the conversion -- adaptor, manifold, throttle, jets, etc etc... and it is too much hassle.

Thumper Talk has a kit for $799USD... but honestly, my bike is worth maybe $3000 right now... to put a $1000+ carb on that seems like a waste. If I need the better performance that badly I will just sell the DRZ and buy something like a KTM which will give me a better carb (or most likely EFI), better brakes, better suspension, lighter weight, etc, etc... much more value for the money, I think.
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Unless your racing, and or have other pretty serious engine mods I don't think it would be worth the money, that or if just have bike part buying problem like me....

My engine in my CRF50 is worth about $4000-5000 so a $800 carb kit isnt really out of place on it, and a FCR would be way too much fuel for anything under a 124cc the bore kit I already had before buying the carb

I think you got the right idea if you want to upgrade sell the DRZ put the money from that and the money you would have spent on mods on one of those orange bikes!

Ive ridden a DRZ, and I have KX450 SM, I know the DRZ is an awesome bike and has a big following but if you've ever had the chance to ride a 450cc or larger SM, either a conversion or one of those off the shelf KTM's youd know there is a serious gap in performance/power compared to the DRZ. There are a lot of good options now for street legal SM style bikes....
 
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JohnnyP636 said:
Unless your racing, and or have other pretty serious engine mods I don't think it would be worth the money, that or if just have bike part buying problem like me....

My engine in my CRF50 is worth about $4000-5000 so a $800 carb kit isnt really out of place on it, and a FCR would be way too much fuel for anything under a 124cc the bore kit I already had before buying the carb

I think you got the right idea if you want to upgrade sell the DRZ put the money from that and the money you would have spent on mods on one of those orange bikes!

Ive ridden a DRZ, and I have KX450 SM, I know the DRZ is an awesome bike and has a big following but if you've ever had the chance to ride a 450cc or larger SM, either a conversion or one of those off the shelf KTM's youd know there is a serious gap in performance/power compared to the DRZ. There are a lot of good options now for street legal SM style bikes....
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+1 I think Mike is making a good decision holding off. the question of having the correct carb, plus the req'd jetting that may require a dyno tune to get right...
 
CV carbs on big singles don't do the engine any justice no matter how spot on the jetting may be. It would be nice to find a clean used pumper kit. All the jetting and tuning info is on www.
 
I had a DRZ with a FCR; it was a TT CARB. I had a 1/8 throttle stumble that I was able to tune out and needed a adjustable leak jet to get things spot on. I sold that bike for too little should of kept it. I was a good time.

My understanding is you need to make sure you have the proper adapter to fit the intake boot and air box boot. The carb is a tight fit but it does work. I believe the TT forums should be able to provide all the information you need. All the best; I agree lots of money; likely better off buying a DRZ with it mounted swap carbs and resell the one you don't want :)


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I had an 07 s model, 3x3 mod, powerbomb header, Yosh exhaust and jd jet kit. Huge difference in throttle response, much more fun to ride. My buddy had a similar setup but also had the Fcr, another big step up. I considered buying the carb kit for a bit. I wound up selling it and buying a blue plated ktm 200 2t, roughly 40hp and 220 lbs woohoo!

Edit: Although the ktm was a total hoot to go "hooning" on occasionally, it was not commuter bike. If you don't live near trails, the ktm requires a trailer (or a frequent rebuild lol).
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Shoot Eddie Sisneros at SSW an email. SSpeedWorks@gmail.com

He could probably answer your question off the top of his head. He's crazy busy though.

BTW. He is no longer with Epic, and is out on his own now
 
It makes no sense to put FCR39 on otherwise stock DRZ engine .... sure it will make some difference, but at what cost and it's still just DRZ after all is said and done. If you get your hands on one for 50 bucks and buy bunch of jets to play around ... it would be a different ballgame.
 
mxs said:
It makes no sense to put FCR39 on otherwise stock DRZ engine .... sure it will make some difference, but at what cost and it's still just DRZ after all is said and done. If you get your hands on one for 50 bucks and buy bunch of jets to play around ... it would be a different ballgame.
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I don't think that applies to those who take the long view.
 
Have you checked out thumpertalk drz400 forum? Lots of knowledgeable drz guys there who can help you with the FCR.

I have a completely stock drz right now. I'm quite shocked a carburetor that seems so popular is $1000 for a bike that I got basically new for $4000. It's too bad we can't convert 450's to street legal bikes here because KTM's are just too expensive and I hear they require much more maintenance. maybe BB kit, FCR and cams are in my future?...I keep flip-flopping on that idea..
 
Anyway, the 3x3 has been done a long time ago. Jetted as well. Had a Powercore 4 on it... got rid of it because it was too damn loud, couldn't listen to tunes via the sena with that pipe. Not sure if the DRZ is worth striving for more. Got a Clarke tank on it though.... a 350km range is nice to have. The non vacuum Raptor petcock seems to make it start much easier too.
 
Motorcycle Mike said:
Anyway, the 3x3 has been done a long time ago. Jetted as well. Had a Powercore 4 on it... got rid of it because it was too damn loud, couldn't listen to tunes via the sena with that pipe. Not sure if the DRZ is worth striving for more. Got a Clarke tank on it though.... a 350km range is nice to have. The non vacuum Raptor petcock seems to make it start much easier too.
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If you're always looking forward, no. Better bikes are being made every year. It might be a philosophical question tho, imho. If you truly enjoy riding the bike, and equally important, wish to exercise technical mastery over the machine you could do worse than anchoring your hobby around the DRZ400. I look to other niche riders for inspiration, the guy whose been racing the same Norton 750 for 30 yrs. or the BMW airhead rider who's riding nothing but for decades. I find something very calming about the guru to one single machine. Yes, he might own three or four of them and you can certainly see the advantage to doing that. Some bikes have the advantage of long production runs, parts and complete bikes can be cheap and if not the cost can be amortized over decades of ownership. Just a thought.
 
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