Quietly Uncork


17 replies to this topic
  • Hoosier

Posted March 10, 2004 - 09:54 AM

#1

Newby 650R old man here. What portions of the uncorking procedure can I perform without making the exaust tip mod. I really need to keep the exaust as quiet as possible because of the areas I ride. The only reason I am planning to do the uncorking is to reduce overheating when riding tight trails. Help?

  • J_T

Posted March 10, 2004 - 01:09 PM

#2

I really need to keep the exaust as quiet as possible because of the areas I ride. The only reason I am planning to do the uncorking is to reduce overheating when riding tight trails. Help?



When you say quite as possible you mean as quite (w/in legal limits)?...or you mean you want stock exhaust sound level no matter what?

The reason I’m asking is b/c many have found exhaust tip mods that remain w/in the legal limit and good performance.

But if you absolutely want to keep stock exhaust uncorking would still help with performance as well as overheating (sometimes a richer mixture helps too) so go for it.

If you could pass on the riding temp you normally ride in, as well as altitude that may help with recommendations and maybe someone with a similar setup could give you a good place to start.

I had a list of jetting people submitted that worked well for them and the closest I had to a similar situation would be a xr650r at 1000 ft above sea level, and temp ~90F. They were using 172 Main, 65 (stock) pilot , stock needle at 4th position (could also try 3rd), with Uni filter, airbox parts removed, Carb insulator upgrade (or bored out), with Stock header, and muffler.

Stock jetting is as follows; 125MJ /65s PJ/ 2nd position of needle

If you lived higher or hotter you would need smaller Main Jet than here and large if you live colder or lower but this is just a suggestion of a place to start.

Keep checking back for more input to verify or suggest otherwise. Oh yea, Welcome!

Hope this helps,
JT

PS Oh yea you will need to adjust the mixture screw afterwards to get full effect, and on Needle clip position, it affects midrange and only takes a little time and no money to change so experiment to what works best with you. I hope you get it worked out...I just saw you were in AL? roughly what part of AL?

  • irondude

Posted March 10, 2004 - 01:52 PM

#3

yeah if ya want a quiet bike--and good for you! -- then just leave it alone. It might be street legal with the mods--but its actually a lot louder IMHO. Modify other stuff like the cam, carb, airbox and side cover, gearing etc.

  • jtc89

Posted March 10, 2004 - 02:07 PM

#4

If you drill out the stock exhaust tip you won't have a very loud bike. It really isn't offensive at all. If you use the HRC tip, as I have done you will get more sound than drilling the stock tip but, it still isn't loud. All the aftermarket systems are much louder that the HRC tip and so are the Harley's. Mine is between 94 and 96 db and not offensive at all. With out letting the volume of air out of the engine you aren't going to get much more in. Remember the motor is just an air pump, to get more in you must get more out.

Also regarding street legality, in Alabama you cannot convert a dirt bike to street use anymore. Dec 31,2003 was the deadline. Unless the state does as California has done and extended the time. The Head guy at dmv told me 12/31/03 was it. I got mine done in Nov 2003.

  • larry650

Posted March 10, 2004 - 03:17 PM

#5

I`ll just report I`m runing the HRC Tip with the Baja Designs baffle and find it a good combination of quiet performance.

  • RidesRed

Posted March 10, 2004 - 03:43 PM

#6

J_T, I see you are running an edelbrock carb. How do you like it?

  • J_T

Posted March 10, 2004 - 04:13 PM

#7

RidesRed, I love it! I'll tell you all the reasons I like it then the reason I bought it which had nothing to do with any of it. :D

I like it b/c It starts great, great throttle resonse, Easy to install and adjust, No jets, better low end response as well.

Why I bought it...I had a uncorked jetted XR650R that wasn't just perfect yet...I had been away at school for over a year when I finaly was going to get a chance to go on some big rides with some buddies. I didn't want to struggle with jetting the only afternoon I had between flying in and riding and it was really running rich and hard to start if it was laid over. It was Aug and the heat and kicking the beast killed me more than riding ever will and I'm 165lb. These rides were big enough that I wanted to just enjoy them. So I bought the Edelbrock QS put it on and had it running after it sitting w/in a few kicks (after putting in fresh gas). A simple external adjustment of the needle and it started and ran great! :)

Maybe my reasons weren't all perfomance related but I am so glad I did. Maybe others can help with their opinions.

  • Hoosier

Posted March 10, 2004 - 06:34 PM

#8

I live in Southeastern alabama so the elevation is, I believe, a couplefew hundred feet and I ride in temp of 55 to 95 deg F. I would like to leave the exaust (noise - Db) as close to stock as possible. So, it sounds like making the rest of the airbox and carb changes are ok without the exaust mod. That's great. I just bought this (2000 650R)bike last sat, took it for a 15 mile ride in tight woods - it quickly earned my respect. I have not been on a bike for about 18 years prior to Dec 2003 when I got the fever. I raced enduros and hare scrambles in Fla/Ga for a number of years then quit cold turkey to raise a Family in 1985. Thanks everyone for the help!!!
One more question - I read that someone makes a good rear tire with a high composition (high density) center for less wear on pavement but still aggressive enough for mostly trail riding.

  • J_T

Posted March 11, 2004 - 01:27 AM

#9

Wow! You are about to get an eye-opener if the bike is new to you and still stock!

b/c I'm the type that would want to make it as efficient as possible I'd have a hard time stopping at stock exhaust but I was thinking...what would your thoughts be about getting a second insert for the stock muffler like an HRC or a drilled stock in addition to your stock. That way if you are in an area that requires quite you can install the stock but if you can get away with the sound you can install the slightly louder yet less restricting one? There are many that use stock header and exhaust just the tip modified and get great performance!

Just an option...I'd still like to get someone to varify jetting for his setup if someone out there has any suggestions! OR if there is anyone that has gotten away with swapping tips and being OK a common carb jetting?

I hope you are liking the Pig so far!

JT

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  • RidesRed

Posted March 11, 2004 - 01:50 AM

#10

I tried that (open intake/stock exhuast) but it did not run well. Now however, the exhuast is opened up as well. And the bike starts, runs, and rides in a most excellent fashion. From personal experience, the intake mods need to be balanced with exhuast mods. Good luck. Welcome to the "club".

  • Hoosier

Posted March 17, 2004 - 10:18 AM

#11

Well the uncorking was accomplished last night - (less the exaust). "Very short" test run went well :D ....except... The engine rpm (still) accelerates from idle to a fast idle on it's own. :D This does not happen unless the engine is warm. And when riding and I turn off the throttle, the engine rpm slows down very slowly to a fast idle. After forcing the rpms down with the engine or clutch, it will stay at idle. I checked the throttle cables and there is some minor slack in both cables.
Does anyone have any ideas what may be causing this? :)

  • TimBrp

Posted March 17, 2004 - 10:35 AM

#12

Sounds like it's running on when you chop the throttle. To lean on the pilot circuit. Try upping the pilot jet a size or two and remember to stick with the "S" style pilots.

  • Dirt4me

Posted March 17, 2004 - 12:00 PM

#13

Mine had that same "hanging"/fast idle problem when hot too. I just uncorked it last week and the problem when away completely. Runs much much better now!

I used this for reference: http://www.4strokes....da/650rmods.asp

2003 XR650R 175 Main, 68S Slow, 3rd Clip Position on the Needle, HRC tip in the stock can, mostly ride in Northern Kalifornia 0-3000' @ 50-90°F

  • Hoosier

Posted March 17, 2004 - 04:38 PM

#14

Today I took the "once tame" 650 on it's first lengthy test ride after uncorking, both on road and off. The hanging rpm problem went away!! :) I left the exaust stock and there does not seem to be any problem. It runs great!! But I have a new problem - I think someone stole my old tame 650 and replaced it with with a PATRIOT MISSILE. :D Does anyone have some extra duct tape? I need some to fasten my posterior to the seat!!!! :D.......... :D

  • J_T

Posted March 17, 2004 - 04:44 PM

#15

Thats great.. :).It sounds like you're really enjoying it! maybe even a little surprised by the outcome.

Can you pass on what jetting you found worked with the stock exhaust?

Thanks
JT

  • irondude

Posted March 17, 2004 - 04:48 PM

#16

cut out the airbox cover, put in a cam, add a pumper carberator, and -- for about $600 clams---you will double the rush.

In fact the hit is so hard, you might have to gear it up a bit just to tame it---110mph off road...those freestylers are wimps!

  • Hoosier

Posted March 17, 2004 - 05:05 PM

#17

I opened the airbox, put a #172 main jet, 68s pilot, stock needle at 3rd from top and bored out the carb insulator/intake. :) Unbelievable difference!!

  • Roll_it_on

Posted March 17, 2004 - 06:44 PM

#18

I'm glad you are enjoying the difference! When you get bored with this try uncorking your exhaust too :) 650cc trying to get pushed out of a dime size hole would be like trying to use a straw as a snorkel. I have the HRC tip in my exhuast and for kicks I put the stocker insert back in and man what a difference. I never rode my bike stock since it was uncorked by the dealer. It must have been a real toad :D





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