• There has been a recent cluster of spammers accessing BARFer accounts and posting spam. To safeguard your account, please consider changing your password. It would be even better to take the additional step of enabling 2 Factor Authentication (2FA) on your BARF account. Read more here.

What did you do to your dirty bike today?

Is that the slant FCR, or the FCR-MX? Had the slant FCR on a DRZ, but I couldn't ever really dial it in like an MX.
 
FCR-MX. I have it dialed in pretty close but I think the main jet is too big, im at 155 now. I have a uni, stock exhaust and a102mm piston with 9.6:1 compression ratio. I need to do a plug reading i guess, but one of those O2 sensors would be ideal. They are $$$$ though so ill do it the old fashion way. I have learned that oil temp is a great way to find out if im lean too.
 
I have some holes drilled in the airbox too but maybe I need a few more. I hear these carbs really need a lot of air.
 
Saltwater said:
I have some holes drilled in the airbox too but maybe I need a few more. I hear these carbs really need a lot of air.
Click to expand...

:rofl Mark..... why am I not surprised your solution to a rich jet would be to just drill some more holes in the airbox! :laughing :twofinger

Cut one six pack out of your budget this week and go buy some brass to sort this out. :x

25mpg aint going to cut it in baja this year!
 
Right on, the FCR-MX is the best 4T carb out there. To improve mileage, I don't think you let in more air to match fuel, but reduce fuel to match air..? Did you have to mess with the accelerator pump timing/duration, or was it pretty much bog-free right out of the box?
 
It was bog free, the carb is off of a 2007 CRF250R which I've read has a better ap pump and linkage. What about leak jet size? I swapped the pilot jet for a smaller one because I was able to turn the mixture screw all the way in and it would still run so it was obviously to rich. It is even more responsive now up to 1/3 throttle and rejects the choke pretty quickly after startup.

CJ, I spent like $50 on all a bunch of jets butch all the mains I have are to big now. And it takes a week for them to get here, I'm anxious for some results. Your right though I'll order some tonight. I'm bringing the XR to the next meet up so you better bring your big boy pants.
 
I don't think you'll find a leak jet size recommendation because your application is too custom. What I ended up doing for an old bike was soldering the leak jet closed and then working my way up with some small drill bits. It sounds hoaky, but it worked great and if you go too big, you can just solder it closed again and start over. Many times closing it fully works just fine, very little bypass is needed, if any.
 
Jets R Us sells a 35 leak jet maybe I'll ad that to the list tonight. Do you think this will improve fuel economy? How about WOT performance?
 
It's just to make sure the motor has fuel while you're actually twisting, otherwise it's invisible. It technically could make a difference with fuel economy, but I don't think it would be noticeable.
 
Saltwater said:
I'm bringing the XR to the next meet up so you better bring your big boy pants.
Click to expand...

Looking forward to riding it. Its the only mod I am considering for the XR. I just dont have the patience to tune it... so I'll continue heckle from the sidelines until you get it ironed out! :teeth

I gave away all the jets that would have worked for your bike when I sold the Husqvarna. Perhaps order larger gaps in in your jet sizes.

Bkye, you have seen his avatar pic havent you? Would you suggest anyone looking like that use a powerdrill on their motorcyle? :wow
 
Hahaha, actually, he looks exactly like any of my riding buddies, we're just a bunch of goofballs too.:p
 
I need to double check which size main I have in there now so it looks like I'll order them tomorrow. Working on my bikes can be a very unique experience CJ, there's no one ever around to see though.
 
Saltwater said:
Ya my XRL is a lazy fuck, its always taking naps on the trail. I love how simple it is so I just keep riding it. By the way the 40mm FCR carb I threw on really woke this bike up, but im getting 29 mpg so it needs somemore tuning.
Click to expand...

My XR got lazy and just sunk right from under me. I don't know why:rofl

Was the new carb after Baja this year? What compression piston are you running in that XRL?

I think my XR4 is coming apart soon. I'm considering the Wiesco 10:1 with as little over bore as possible. I want it to run on that Baja swill we found down there.
 
Last edited:
I'm amazed that my finicky KTM could handle whatever gas we were getting out of those barrels. :laughing Good thing for the "shitty fuel" map setting. :thumbup
 
Ya Tom the carb was after Baja. In fact my 5.8 acerbis doesn't quite fit from how high the throttle cables come up so I was thinking of getting a heat gun and reshaping a small portion under the tank. The piston I have now is 9.6:1 and works perfectly (stock is 8.3). I didn't want to go any higher because im air cooled and I can't run shitty gas. The bike did ping some with that backyard barrel fuel.
 
Got a new, to me, 09 300 xc-w.

photo_zps2fdcd854.jpg
 
^^^Nice! I think this generation is the best looking. :thumbup
 
I actually don't really like the way it looks. Too much black/orange. Not a big fan of that combo, too dark. Needs a little white.
 
Saltwater said:
Ya Tom the carb was after Baja. In fact my 5.8 acerbis doesn't quite fit from how high the throttle cables come up so I was thinking of getting a heat gun and reshaping a small portion under the tank. The piston I have now is 9.6:1 and works perfectly (stock is 8.3). I didn't want to go any higher because im air cooled and I can't run shitty gas. The bike did ping some with that backyard barrel fuel.
Click to expand...

Got it. I hope you can get that tank back on correctly. I believe it is new piston time for me and I'm looking at the Wiesco 10:1. Just like you, I don't want super high compression as I don't want to deal with detonation. The XR4 is 9.3:1 stock.
 
That trials tire looks hammered. Are you going to put a new one on there? I want to try one really bad on my CR but I'm afraid I won't like it.
 
You must log in or register to reply here.
Back
Top