XR650R Main Jet 175 ?RD?

[ThumpThis]

I recently ordered the typical jets for the uncorking of the pig. I put in an order for the 175 main jet. I did all this before pulling out the carb to see what was already in there. Of course the bike already had the open insulator, and tuned jetting.(except it has a 65S pilot, so I get to change one thing at least) But the main jet was a 175 RD. I did some research and found that it stands for Racing Designs and it is a tiny bit different than the regular 175. Anyone have any clue about this thing?? Should I just throw in the 175 that I ordered?

Just curious, the bike ran pretty damn good prior to me pulling the carb, but I like to take things apart and hopefully get them back together anway. I was hoping it hadnt been completely uncorked, because I want more power . Already has a White Bro's E series and the airbox unplugged.


Suggestions? Knowledge on the RD? Who Cares?

Thanks in Advance

[oldxr]

On my xrr I found a 178 to run best.California gas is %10 ethonol so that leans it out vs real old school gas.There is post on thumpertalk xr600/650 forum about a guy that milled .050"off of the bottem of the throttle slide to get the off-idle throttle response better.Even with the b53e needle at 4th slot down from the top on a dyno run I was showing a lean range from 1700 to 3500 rpm .I had a nearly new eldo carb for the bike so I switched it out.Dyno run with stock carb made 46+.The eldo made 43+ but the dyno was showing rich with a 21e needle ar 15 clicks up.I switched it to a 20e needle at 13 clicks from lean but I havent been back to the dyno.The best way to tune is to get a wide band o2 gauge set up and read you a/f while riding.Then tune for max hp with the main jet using dyno runs.the good thing about the oem carb is that it is very simple and trouble free.

[Sierra Thumper]

Originally Posted by ThumpThis

I recently ordered the typical jets for the uncorking of the pig. I put in an order for the 175 main jet. I did all this before pulling out the carb to see what was already in there. Of course the bike already had the open insulator, and tuned jetting.(except it has a 65S pilot, so I get to change one thing at least) But the main jet was a 175 RD. I did some research and found that it stands for Racing Designs and it is a tiny bit different than the regular 175. Anyone have any clue about this thing?? Should I just throw in the 175 that I ordered?

Just curious, the bike ran pretty damn good prior to me pulling the carb, but I like to take things apart and hopefully get them back together anway. I was hoping it hadnt been completely uncorked, because I want more power . Already has a White Bro's E series and the airbox unplugged.


Suggestions? Knowledge on the RD? Who Cares?

Thanks in Advance

Cut your airbox top or sidecover (with screen mesh behind the sidecover) to get more airflow. Suppose to work well on the xrr's. Worked well on my xrl

[RideFreak]

As you know, jets meter fuel or air. Racing designs sounds like a name to convince buyers that their jets are better. The Keihin FCR carbs, one of the most evolved MC carbs on the market utilize standard jets, as do most motorcycles. Nothing special because all they are is a precise orifice. the point where the main jet sits in the carb (at the very bottom) no atomization occurs, I doubt you'd detect a difference between it and a regular 175 if there is infact a difference.

[Beezer]

I don't know who RD is but I know that Kehin, Mikuni, and Dynojet all have different size holes for the same number. be careful when you switch brands

Carb Jet Size Cross Reference:Keihin/DynoJet/Mikuni

---

Width------Keihin # -- DynoJets # -- Mikuni #
0.0350---- 92.5--------- 92-----------86.3
0.0360---- 95----------- 94-----------88.1
0.0370---- 97.5--------- 96-----------90.0
0.0380---- 100---------- 98-----------91.9
0.0390---- 102.5------- 100---------- 93.8
0.0400---- 105--------- 102---------- 95.6
0.0410---- 107.5------- 104---------- 97.5
0.0420---- 110--------- 106---------- 99.4
0.0430---- 112.5------- 108--------- 101.3
0.0440---- 115--------- 110--------- 103.1
0.0450---- 117.5------- 112--------- 105.0
0.0460---- 120--------- 114--------- 106.9
0.0470---- 122.5------- 116--------- 108.8
0.0480---- 125--------- 118--------- 110.6
0.0490---- 127.5------- 120--------- 112.5
0.0500---- 130--------- 122--------- 114.4
0.0510---- 132.5------- 124--------- 116.3
0.0520---- 135--------- 126--------- 118.1
0.0530---- 137.5------- 128--------- 120.0
0.0540---- 140--------- 130--------- 121.9
0.0550---- 142.5------- 132--------- 123.8
0.0560---- 145--------- 134--------- 125.6
0.0570---- 147.5------- 136--------- 127.5
0.0580---- 150--------- 138--------- 129.4
0.0590---- 152.5------- 140--------- 131.3
0.0600---- 155--------- 142--------- 133.1
0.0610---- 157.5------- 144--------- 135.0
0.0620---- 160--------- 146--------- 136.9
0.0630---- 162.5------- 148--------- 138.8
0.0640---- 165--------- 150--------- 140.6
0.0650---- 167.5------- 152--------- 142.5
0.0660---- 170--------- 154--------- 144.4
0.0670---- 172.5------- 156--------- 146.3
0.0680---- 175--------- 158--------- 148.1
0.0690---- 177.5------- 160--------- 150.0
0.0700---- 180--------- 162--------- 151.9
0.0710---- 182.5------- 164--------- 153.8
0.0720---- 185--------- 166--------- 155.6
0.0730---- 187.5------- 168--------- 157.5
0.0740---- 190--------- 170--------- 159.4
0.0750---- 192.5------- 172--------- 161.3
0.0760---- 195--------- 174--------- 163.1
0.0770---- 197.5------- 176--------- 165.0
0.0780---- 200--------- 178--------- 166.9
0.0790---- 202.5------- 180--------- 168.8
0.0800---- 205--------- 182--------- 170.6
0.0810---- 207.5------- 184--------- 172.5
0.0820---- 210--------- 186--------- 174.4
0.0830---- 212.5------- 188--------- 176.3
0.0840---- 215--------- 190--------- 178.1
0.0850---- 217.5------- 192--------- 180.0
0.0860---- 220--------- 194--------- 181.9
0.0870---- 222.5------- 196--------- 183.7
0.0880---- 225--------- 198--------- 185.6
0.0890---- 227.5------- 200--------- 187.5

[ThumpThis]

Here check this out

http://www.motofanat.com/snow/12047/160/9840018.php

[RideFreak]

Originally Posted by ThumpThis

Here check this out

http://www.motofanat.com/snow/12047/160/9840018.php

That's what I thought, RD is a brand name. Looks like a Russian company that deals in snowmobiles. I'd order stock jets made by Keihin unless of course you live in Russia, then I'd buy Vodka and a snow machine

[ThumpThis]

Originally Posted by RideFreak

That's what I thought, RD is a brand name. Looks like a Russian company that deals in snowmobiles. I'd order stock jets made by Keihin unless of course you live in Russia, then I'd buy Vodka and a snow machine

HAHAHA

yea the stock jets will be here teusday. I will replace everything with the new stuff.

If anyone needs a cheap insulator, I will mail it out.

spanks for the input