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93 XR650L Questions.

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Ok, new guy here, but I used to be here a long time ago (I used to be corndog67, but that seems to have disappeared, someone hacked my msn account, it's not like I'm in the witless protection program or anything), I've had older XR's, CR's, a YZ450F and probably 35-40 other bikes over the last 39 years of riding. So this isn't my first rodeo.

I just bought a 93 XR650L, big fin head, fresh valve job, HRC cam, ported by XR's Only, JE 675cc piston at 10.5:1, Carillo Rod, all freshened up, stock carb and stock pipe, but it came with an XR's Only pipe that the previous owner deemed way too loud for his tastes. The guy did a really nice job on this bike, very, very well detailed, and I haven't found anthing hinky at all about it. It runs cleanly with the stock pipe/carb setup, other than a little bit of popping on decel, but the issue I have is that after the initial big thump through the middle of the rpm range (no tach, so it's a guess where it's running, but it isn't wound tight at all), it seems to run out of beans a little early. Years ago, my buddy had a Muzzy built XR600 (XR628), that I remember had a load more top end than this bike. Would I be correct in assuming that the stock carburetor and pipe are choking this sled down? I believe the valve sizes are stock.

I read another thread about using an FCR off of a CRF450R on there, would that wake this beast up? Along with the XR's Only pipe?

One other question. It has a 19in. wheel on the front right now, with a big rotor kit, along with an extra set of dirt wheels (21 and 18), and a 17 on the rear for the street set up. I was considering putting a 19 in dirttrack tire on the front, like an old DTII Goodyear or Pirelli MT53, or whatever they are currently using out there right now. Or would it be a better idea to lace up a 17 and just use supermoto tires or full street tires?

Any opinions or advice would be appreciated.

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My thoughts:

I tend to keep my bike in the lower rpm range where it seems happiest so keep that in mind when you read on.

I installed a 41mm FCR off of a CRF450R on mine... it did a great job of waking up the bike as far as making the throttle response much "snappier". I did not notice much of a difference in the powerband though.

If the bike is popping on decel, you may have some jetting to do. A lean pilot shouldn't cause the bike to sign off early though.

Our motors are pretty similar... The butt dyno says that the FMF pipe did add a bit to the upper midrange. Enough to warrant a couple of dead presidents... probably not!

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You can buy the optional baffle insert from XRs Only and it takes the edge off the sound. I highly recommend it. It's still going to be pretty loud, just not offensively loud.

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It runs cleanly with the stock pipe/carb setup, other than a little bit of popping on decel, but the issue I have is that after the initial big thump through the middle of the rpm range ..... it seems to run out of beans a little early.

Would I be correct in assuming that the stock carburetor and pipe are choking this sled down?

Yes, you would. All that nice work done to the engine only to make it blow through a stock exhaust....ouch. Is the header stock as well? If so, I would look at getting one of those too. I wouldn't expect the stock carb to be a huge bottleneck in the power department, but a pumper will probably still show an increase and definitely will improve throttle response and fun factor.

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Yes, the headpipe is the stocker. And yes, throttle response is kind of sluggish, at least compared to my YZ450F or the Ducati that I usually ride. It takes a bit of effort to loft the front, I'd like to snap it up a bit, as far as throttle response goes. It definitely feels like it's being held back. Thanks for the replies.

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Yes, the headpipe is the stocker. And yes, throttle response is kind of sluggish, at least compared to my YZ450F or the Ducati that I usually ride. It takes a bit of effort to loft the front, I'd like to snap it up a bit, as far as throttle response goes. It definitely feels like it's being held back. Thanks for the replies.

I found that my bike was not "trail ready" with the stock carb as it would not loft the front wheel easily without using the clutch. I had too many times where a hidden treasure would present itself unexpectedly and I would have to either try to dodge it or torpedo it as carrying the front end over it wasn't an option unless I saw it coming. The FCR pumper gives the pig the ability to snap the front end up and over stuff where it previously could not (without clutch). :thumbsup:

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