XRR needs more topend


53 replies to this topic
  • weskc35k

Posted November 24, 2007 - 09:39 PM

#41

Who mills the lobe from a cam ***.
This is getting weird i'm outta here.

  • HawkGT

Posted November 24, 2007 - 09:53 PM

#42

FWIW, I've seen 102 (GPS) on mine with 15/49 gearing (which works out to slightly taller gearing than stock) on pavement. I'm running a Moriwaki system w/ spark arrester and the standard uncorking stuff. That particular day I was running Kenda K270's at ~14psi, 840ft elevation, maybe 70 degrees. I was tucked out of the wind and remember holding WOT for a good little bit. I was racing to a hospital in Parker AZ after my bud caught a barbed wire fence with his neck! :thumbsup:


Typically it seems like I can get 90 somewhat easily but after that it's kind of a slow climb to triple digits. And environmental conditions seem to make a noticeable difference in top speed.

  • The Italian Stallion

Posted November 25, 2007 - 10:03 AM

#43

Something sounds wrong here. I thought a 650R would do 90 to 100 with stock gearing.


I hear you bro. My pig hits 80 mph in fourth gear with ease [on the pavment] with 15 45 gearing uncorked and jetted with just a big gun slip on and a stock head pipe. It goes well over 100 in fifth and my engine is getting a little long in the tooth.

  • zipper600

Posted November 25, 2007 - 12:24 PM

#44

Bigger diameter headers.
Ixil pipe
jetted (170 main,60 drilled pilot)
CRD airfilter
shaved head surface (more compression)
rewinded ignition coils (stronger spark)
Carb boot shaved
Iridium spark plug
Prox piston(cutted skirt,lighter)
95 octane gas(minimum.sometime 100 octane)

my 94 xr600 top speed is 95mph with 15/43.till 85 mphis a blast.after that is difficult.only road use.hits rev limiter till 4th gear easily but after that with fully open throttle its hard to get more top speed(never hitted rev limit in 5th gear) but i think its because of Ixil pipe.Its too open so i decided to swap it for a KTM 660 SMC stock pipe.This way i think i will not loose power but will reduce noise..its too open,too loud..

  • BWB63

Posted November 25, 2007 - 02:00 PM

#45

In the dirt on a very dry and fluffy lake bed (can see the dust cloud for many miles) 15/48 gearing I turned 102mph, GPS, this last weekend. I could hear the rev fromm the wheel spin from 98mph on. I pushed my rear back to try and get better traction. It gets a little nerving as the bike starts to fish after 100mph. The lake bed has become soft from not rain and the constant grinding of those seeking ear to ear grin of fun. Trucks doing donuts, kicking up thirty plus foot roosts.

  • brad21

Posted November 25, 2007 - 04:07 PM

#46

I hit 90 (GPS) on a long dirt section the other day. My bike is stock 14/47, FMF full Powercore 4 that's got a cork in it, open airbox, uncorked, stock otherwise, 2000 model brp.

  • Thumpage

Posted November 28, 2007 - 11:26 PM

#47

Rubbish they don't use the HRC all the time as they worry about fuel quality in Mexico.
There is no pumping losses in a motor that only revs to 8 or 9k,your story is not quite right.
This is HS.


Well, to clear up a part of my point, I don't think Honda relies on using iffy gas down in baja. The Honda Team pits are sure to be using quality supplied gas. :thumbsup:

Also Quoted; "Who mills the lobe from a cam ***.
This is getting weird i'm outta here."

Too funny, he said milling the top of a piston, not a cam lobe. :busted:

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  • weskc35k

Posted November 29, 2007 - 01:44 AM

#48

OK so who mills the top off've a HRC piston..really do you know anyone who's done it.
I used to work for Honda Australia and i've never heard of anybody with tech knowledge doing it.
The HRC piston is 11.5 to 1 nothing really, Steve Hengevelt commented that they don't allways use it(HRC piston) in the Baja because of fuel issues,he might know.
Steve has just broken a land speed record on a crf450 too i believe.I think it had a hi comp piston in it.
Anyway use it or don't use it, mill it,don't mill it i don't give a toss.
PBWT.

  • Thumpage

Posted November 29, 2007 - 01:49 AM

#49

Thumpage
I agree: getting the bike to run as cleanly as possible is the first order to getting the most out of the motor. I am not one to throw money at problems expecting a solution.
I'm one of those guys that can feel the difference in gas brands/octanes, when all around me say I am crazy. When I started with two-strokes, I matched, ported, and polished motors for me and my friends, and learned quickly that everything has a compromise when you try to go with 'more'. I know that getting the Edle dialed in will give me the most of what i want right now: 'better' power, opposed to 'more' power.
Having said all that, getting a bit more top end without having to gear up would be nice. I really like the stock gearing for dirt, but would like to accelerate to 80 mph as quickly as possible, as LA fwys are nutty to be on without superior power.
So, I plan to do these things, in no specific order, to get the bike 'better' before I go 'bigger':
- learn the edle's tuning and go as rich as is practicle
- replace my rear blown shock, and go with heavier springs
- get the front and rear shim stacks redone by ESP
- replace plastics as they become (cheaply) avialable on ebay
- find a reasonably priced full exhaust (I really think the stock header is part of the problem with over-rev)
- get a comp/speedo (I want to see revs)
- new chain and sprocket
- get the valve train freshend, do a bit of home port/polishing, and while I'm at it, try a new hotte cam.

I ride the thing almost everyday right now, and do an occasional 'questionable' trail ride near my Chatsworth home. I don't think I will have the confidence to do a 'real' ride till the rear boinger is fixed (pretty boingy now).
-


Krannie,

I think you have a good idea of what the bike could use. Going with a aftermarket header will allow the bike to climb stronger in the midrange through top end. I noticed it right away when I made the change. The stock header is great for low to low midrange and works very well for general riding on trails and mixed terrain. The drawback is that the motor just noses over when getting up past the midrange in more wide open riding. With the aftermarket header it woke up in the upper revs in the higher gears.
As for the port and polishing, it seems you have some good experience, just be careful. It has been reported that the XR650Rs ports are plenty big, even with use of hotter cams.
What I remember reading is Precision Concepts would do only very minor 'clean-up' of the ports on the Honda Team XR650Rs and that was all.
There have been reports from various people of their bikes losing power when they had porting done with only other minor mods, at least in the low-mid range.
You live in my old neck of the woods!

  • Thumpage

Posted November 29, 2007 - 02:17 AM

#50

OK so who mills the top off've a HRC piston..really do you know anyone who's done it.
I used to work for Honda Australia and i've never heard of anybody with tech knowledge doing it.
The HRC piston is 11.5 to 1 nothing really, Steve Hengevelt commented that they don't allways use it(HRC piston) in the Baja because of fuel issues,he might know.
Steve has just broken a land speed record on a crf450 too i believe.I think it had a hi comp piston in it.
Anyway use it or don't use it, mill it,don't mill it i don't give a toss.
PBWT.


Actually, I wouldn't know. It was Billahjack on post #38 that mentioned it. Maybe he could shed some more light on that.

  • weskc35k

Posted November 29, 2007 - 03:53 AM

#51

My dyslexic.

  • Krannie McKranface

Posted November 29, 2007 - 07:24 PM

#52

Krannie,

I think you have a good idea of what the bike could use. Going with a aftermarket header will allow the bike to climb stronger in the midrange through top end. I noticed it right away when I made the change. The stock header is great for low to low midrange and works very well for general riding on trails and mixed terrain. The drawback is that the motor just noses over when getting up past the midrange in more wide open riding. With the aftermarket header it woke up in the upper revs in the higher gears.
As for the port and polishing, it seems you have some good experience, just be careful. It has been reported that the XR650Rs ports are plenty big, even with use of hotter cams.
What I remember reading is Precision Concepts would do only very minor 'clean-up' of the ports on the Honda Team XR650Rs and that was all.
There have been reports from various people of their bikes losing power when they had porting done with only other minor mods, at least in the low-mid range.
You live in my old neck of the woods!


Thumpage, what exhaust are you running?

  • Thumpage

Posted November 30, 2007 - 03:25 AM

#53

I use the FMF Hi-Flo header with the now discontinued White Bros. Pro Meg muffler.
I chose the Hi-Flo header over the Powerbomb because it has plenty of clearance from the Edelbrock's pump screw. The power bomb module on the Powerbomb header is known to butt up against the pump screw. Guys will either slightly tilt the carb or put a little dent in the powerbomb module to give clearance. No big deal, I just preferred the better fitment compatability of the Hi-Flo/Edelbrock combination. Of course, to each his own. Both perform their duty, just somewhat different in power character.

My bike pulls noticably stronger from midrange on up. It gained a healthy upper midrange surge. The power did soften up somewhat right at the very bottom. It doesn't have that spike of power that the stock header has way down low. Still plenty of grunt though of course, just not that initial bottom burst right above idle. It seems it is the stock headers diameter reduction about 3" from the head that gives that strong bottom surge, but at the cost of really flattening out in the upper midrange.
When you are talking about getting on the gas & accellerating through the upper gears and keeping at higher speeds a larger aftermarket header makes a marked difference, without doubt.
From what I have read and the look of the design & contructiuon, I like the XRs Only header also. They are a bit pricey but are supposed to be good.
Here is a couple links to the best price I have known about on the FMF headers. They carry both the Hi-Flo & Powerbomb. The Powerbomb is slightly less expensive here than what Rocky Mountian offers it at but Rocky has free shipping. This company will price match if their combined price with shipping is more. Rocky Mountain doesn't carry the Hi-Flo header though, so no comparison there.
Both are a great price listed at the links below, especially the Hi-Flo compared to anything out there.
http://www.motorcycl...ct_id=FMF040078

http://www.motorcycl...uct_id=FMFH426H

  • Krannie McKranface

Posted November 30, 2007 - 07:04 AM

#54

I use the FMF Hi-Flo header with the now discontinued White Bros. Pro Meg muffler.
I chose the Hi-Flo header over the Powerbomb because it has plenty of clearance from the Edelbrock's pump screw. The power bomb module on the Powerbomb header is known to butt up against the pump screw. Guys will either slightly tilt the carb or put a little dent in the powerbomb module to give clearance. No big deal, I just preferred the better fitment compatability of the Hi-Flo/Edelbrock combination. Of course, to each his own. Both perform their duty, just somewhat different in power character.

My bike pulls noticably stronger from midrange on up. It gained a healthy upper midrange surge. The power did soften up somewhat right at the very bottom. It doesn't have that spike of power that the stock header has way down low. Still plenty of grunt though of course, just not that initial bottom burst right above idle. It seems it is the stock headers diameter reduction about 3" from the head that gives that strong bottom surge, but at the cost of really flattening out in the upper midrange.
When you are talking about getting on the gas & accellerating through the upper gears and keeping at higher speeds a larger aftermarket header makes a marked difference, without doubt.
From what I have read and the look of the design & contructiuon, I like the XRs Only header also. They are a bit pricey but are supposed to be good.
Here is a couple links to the best price I have known about on the FMF headers. They carry both the Hi-Flo & Powerbomb. The Powerbomb is slightly less expensive here than what Rocky Mountian offers it at but Rocky has free shipping. This company will price match if their combined price with shipping is more. Rocky Mountain doesn't carry the Hi-Flo header though, so no comparison there.
Both are a great price listed at the links below, especially the Hi-Flo compared to anything out there.
http://www.motorcycl...ct_id=FMF040078

http://www.motorcycl...uct_id=FMFH426H


Wow, that is good pricing. I had the same set up on my previous XRR too. I am thinking about going with the Barnum's pro setup. Still weighing the $.......





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