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15/47 XRR and Top Speed (dirt)

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OK i need so help...i think my pig is sick

did a 500 mile long ride this weekend and i was testing out my new gearing... My 2000 XRR would NOT pull 90 with this gear set up...what is wrong?

I have a fully uncorked motor, open'd airbox, full PC pipe and the stock carb (Jetted with a 68s, Comp Needle and 168 main - ride sea level to 4000 at 60-90 degrees).

Valves were in spec before the ride.

Any ideas or is this all the bike will do?

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alot depends on how the engine is, if its not quite fresh it may be lacking some and thats why, whats with 90 mph? that a goal you wanna get to?

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As you maybe know, sometimes bikes are geared to do very high speeds(in theory) but the motor does not have the power to rev out that ratio.

Wind resistance starts playing an important role, your weight, condition of engine etc. Also double check any dragging/binding brakes.

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alot depends on how the engine is, if its not quite fresh it may be lacking some and thats why, whats with 90 mph? that a goal you wanna get to?

90 mph is not a goal, i just expected more out of this bike. How does my jetting look?

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ur geared a little higher than the 14/48 stock....

but unless ur spending most of ur time at 4000' rather than sealevel a 175 main jet may be better...:)

the other big variable is the "dirt" ur trying to hook up on...u can usally count on the tire spinning faster than the bike is getting pushed forward offroad... :banghead:

...that being said ur speed does seem a bit down unless ur rear tire is really worn out.

:banghead:

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ur geared a little higher than the 14/48 stock....

but unless ur spending most of ur time at 4000' rather than sealevel a 175 main jet may be better...:)

the other big variable is the "dirt" ur trying to hook up on...u can usally count on the tire spinning faster than the bike is getting pushed forward offroad... :banghead:

...that being said ur speed does seem a bit down unless ur rear tire is really worn out.

:banghead:

I will try bumping the main...what about the pilot and the needle?

as for the tire...well its was brand new and the top end test was on a oil'd down dirt road...almost like the pavement.

i did a search and a guy on there said he hit 107 with this gearing...

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Your main is a little small, you can run a 172 or a 175 and it should help out.

Your bike should be able to run at 100mph (with no wind). Even a little head wind will cut your speed down by a large margin.

I did 97.6mph on Thursday on Morelia Rd (dirt) with my XRR.

I have had mine GPS at 108mph (on pavement, 15/46, with a nice tailwind and slightly down hill).

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Your main is a little small, you can run a 172 or a 175 and it should help out.

Your bike should be able to run at 100mph (with no wind). Even a little head wind will cut your speed down by a large margin.

I did 97.6mph on Thursday on Morelia Rd (dirt) with my XRR.

I have had mine GPS at 108mph (on pavement, 15/46, with a nice tailwind and slightly down hill).

Bumpin the main it is...what clip are you so cal guys running on the needle? also what pilot..right now i have 68s should i go to the 70?

The bike was a pain to start in 40 degree for the first start of the day but after that it was a one kick wonder

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where do you live and ride here in Cali?? from sealevel to about 2k feet will react the same for jetting, once you get about 3k and up will you feel the bike is a bit rich if your set good for sealevel area.

You need to have bike jetted for your lowest riding, and thats good for you since you say you ride up to 4k sometimes, will be a tad rich but thats fine.

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where do you live and ride here in Cali?? from sealevel to about 2k feet will react the same for jetting, once you get about 3k and up will you feel the bike is a bit rich if your set good for sealevel area.

You need to have bike jetted for your lowest riding, and thats good for you since you say you ride up to 4k sometimes, will be a tad rich but thats fine.

I live in San Diego (Ramona) which is about 2000 feet elevation. I do dual sport rides up into the mountains so thus the 4000 range and then i also ride baja/desert which is sea level...its a crap shoot but i think if i jet for the 2000 range ill be set.

Also at the 2000k range, what do you recommend for the needle clip?

Hope this fixes top end speed :)

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b53e neddle at middle clip. 180 main, if that made a better power I would check the plug and go richer leaner from there. My stock motor with full exhaust was running a 185 main, 70s needle, b53e middle clip I was a tad rich (where I like it) at 2200' above sea level. California 60~110 degrees.

http://borynack.com/XR650R/xr650r_caruretor.htm

http://borynack.com/XR650R/

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I live in San Diego (Ramona) which is about 2000 feet elevation. I do dual sport rides up into the mountains so thus the 4000 range and then i also ride baja/desert which is sea level...its a crap shoot but i think if i jet for the 2000 range ill be set.

Also at the 2000k range, what do you recommend for the needle clip?

Hope this fixes top end speed :)

wouldnt be much change for 2k feet over sealevel so thats all good

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i might have an extra B53 needle if you dont have one already

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OK i stopped by the local shop on my way home...i bought i 178 and 180 main along with a 70 pilot...

I changed mains....i had a 175 in the bike (opps i was wrong in my first post) and replaced it with the 180

took it for a spin and i hit 96....i noticed a stronger mid range....i still fill i can get more out of the bike so next week i will pick up a 182 and 185 to test.

as for the pilot, i replaced the 68s with the 70...i adjusted the fuel screw to two turns out...the bike doesnt pop as much on deceleration and is strong all the way through the range from idle to 3/4 throttle (thus thinking a 182 might be the ticket)

What do you guys think a 70s pilot would do?

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Well, now that you are going the right direction I would check the plug. Maybe go fresh BRK7EIX and take it for a WOT spin and check color. I hate it when I am right.

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Maybe go fresh BRK7EIX and take it for a WOT spin and check color. I hate it when I am right.

What is a BRK7EIX - a plug? if so what is the advantage over a stock plug?

What is the proper way to do a WOT plug color check?

I hate it when I am right.

:):banghead: :banghead:

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I hate it when I am right.

We do too cuz your head swells and you get all crazy on the 680! :banghead::)

Plug chops- its for testing that particular range of the jetting or throttle position, each jet/needle controls a specific range of throttle. SO doing a WOT aja wide open throttle, test will check your main jet, which is what is working at full throttle. You install a new plug and take the bike out and get about 3rd or 4th gear and pull wide open for a little bit and cut the enging off while coasting back to wherever your gonna pull the plug back out. Now you can do this for any range of throttle position and check a particular range of jetting. Dont do this on a cold engine obviously! but you get bike nice n warm and put a new plug in and dont tighten right away, finger tight the plug in and let it get warm to the temp that the enging will be at since its warm, after a few mins it will be same temp and you can snug the plug and fire up bike and get in a nice open space and in say 4th gear kinda easy cruising you go to wide open and hold it while it runs up to high rpms, then you let off, hit the clutch in, cut the engine and roll back and pull the plug. Will give you a decent reading of how the jetting change affected and if its good.

ranges that jetting controls

closed to about 1/4 throttle is pilot

1/4 to about 5/8 is needle

5/8 to wot main

thats about but if you know where each is you can troubleshoot yourself, say if its bogging or lagging when you first crack throttle coming out a corner you know its in the pilot range and can narrow down a bit where you need to adjust

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