XR650R Carb on a XR650L



258 replies to this topic
  • Kenzo

Posted January 22, 2009 - 08:08 AM


jlutty, i know u like theory, charts, programs, etc...BUT i'll bet a dollar against a dounut that ur too rich on ur main...based on real world results :lol:

...did u try opening the airbox cover? ...how about closing off sum of the airflow? these are both simple and effective methods to test where ur jetting is(too rich or too lean)...

the charts ur using is for an R(BIG DIFFERENCE)...given equal mods the R will produce ~8-10HP more than the L...have u taken that into account?

i believe there are at least 3 to 4 people that have had gud results with much lower jetting...ur pilot is probably ok with the 70s pilot(two sizes up from 65s) but ur main is like eight sizes up from a 160 and this is where ur reporting problems :lol:

re-drilling the jet is a hack job at best...and afterwards even if it works u don't really know wut ur jet size is.

one thing that u need to be aware of is the bike will now be VERY SENSITIVE to throttle changes...after it got mine dialed in i thought i still had a slight stumble at/near WOT...i discovered it wus actually me introducing a very slight change in throttle input :lol:

keep us updated,

:banana:

  • jlutty650l

Posted January 22, 2009 - 01:29 PM


It is warmer today- 62 degrees at ride time.

The 180 was nasty. I tried the 175 again at the 3rd clip position and it was much improved. Then, I drilled out a 160 to about 168. Then it started to work correctly. You can drill jets. It's not voodoo. I have a set of jeweler's drill bits and if you have a bit that is too big and one that is too small and OCD, you drill the bastard out and throw it in; after you write on it with a permanent marker what size you think it is. Or scratch it in. or whtever.

I am throwing darts since I never rode a 650R, I have no idea what the carb is supposed to be like.

At this temp, the 70s works well enough that the bike starts and runs at 1 turn. Great. What about when its 90? I am ordering the 68s.

Remember, the cam makes it run richer, the header + muffler = 2 jets up. or one jet and one needle position. So, with a header, it needs more jet, the porting can also make it run richer, but what did compression do?

I'll refrain from comment on the 8-10 hp difference. I think my nose is bleeding. I can guess that since all I have to jet this bike is trial and error, I'll just keep going.

I will step down the pilot, use my drilled 165/168 ish main, until I get the right ones, and party on.

I am searching for part numbers on the jets.

  • Kenzo

Posted January 22, 2009 - 04:27 PM


I am ordering the 68s and a 165 and 168 main.


:lol: :lol: :p

Oh Snap! :lol:

i just realized ur from Missouri...the “Show Me State” A name attributed to Representative Willard Van Diver. It conotates a certain self-deprecating stubbornness and devotion to simple common sense...

...that's why u like all those calculators, charts, programs, etc... :p

on a serious note wut makes u think the pilot is too big??? ...wut happens when u turn the fuel screw all the way in??? ...and how many turns out until the idle peaks (this is after the bike is warmed up & idle adjusted)??? ...u get'n any exhaust pops/burble on decel when u chop the throttle from WOT???

with the AVC disabled u'll need a fatter than normal pilot :banana:

:p

  • jlutty650l

Posted January 22, 2009 - 06:20 PM


R[/B](BIG DIFFERENCE)...given equal mods the R will produce ~8-10HP more than the L...have u taken that into account?
:banana:


Yes. I was looking for steps initially and just started with those numbers for a benchmark. Horsepower is from air flow, which can be increased through better parts matching and porting and undercut valves, etc. This can require less jetting. Jets react to "Delta P". VE fills cylinders, right? There must be more vacuum through the carb when the cylinder is filling better (more VE). Higher velocity air will draw more fuel as a result of the pressure differential. Better flow, more air, and more power do not automatically equal bigger jets; just the CORRECT AF ratio, right?

Can the need for smaller jets after only a cam swap be attributed to the inefficiency of the carb or the inefficiency of the cylinder fill prior to a cam swap?

8- 10 more horses with equal mods? Are they not 8-10 more to begin with? Do bigger valves, higher compression, and a better carb help? Of course they do.

Percentage gains are what matter to me. I just like to tinker. And I like to feel the results. I found some dirt tonight and like how the bike ignores hills now.

You know as well as I that an L with cam, compression, porting, and an aftermarket header and muffler pipe will be just as nasty on the dyno as un- corked, otherwise stock, R

Read that carefully. Start or finish a range war. Read it the way I wrote it. Uncorked, otherwise stock R vs. Piston, cam, porting, header, muffler, filter, carb'd L. Not very different in power. All the other ways still, yes. But for a bike with E- start and no water pump, not bad, huh?

I have our trade shows in four states over the next six weeks. After that, I hope I have the cash for a dyno day.

My curiousity is killing me.

Any bets?

I am guessing that I picked up ten ponies over stock. A net gain of eight at the wheel?

  • jlutty650l

Posted January 22, 2009 - 06:35 PM


:lol: :lol: :p

Oh Snap! :lol:

i just realized ur from Missouri...the “Show Me State” A name attributed to Representative Willard Van Diver. It conotates a certain self-deprecating stubbornness and devotion to simple common sense...

...that's why u like all those calculators, charts, programs, etc... :p

on a serious note wut makes u think the pilot is too big??? ...wut happens when u turn the fuel screw all the way in??? ...and how many turns out until the idle peaks (this is after the bike is warmed up & idle adjusted)??? ...u get'n any exhaust pops/burble on decel when u chop the throttle from WOT???

with the AVC disabled u'll need a fatter than normal pilot :banana:

:p


This outta be good.

A devotion to common sense would preclude the need to be educated; although the two are not mutually exclusive, just harder to find together.

I am originally from WATKINS GLEN, NY. A road- racing town with a nice state park in the middle of Wine Country where once a year, Nascar visits. There was a little rock festival there in 1973, too. It's a cool town with a strong horsepower culture. If you put green forests, soft dirt, West Coast motor lust and Nor Cal politics in a blender with vineyards and salt factories, then sent 90 percent of the people elsewhere while it snowed all winter, that's it!

I reside in Missouri. Yes. its true. But I belong here, because I am as stubborn as a Missouri mule.

I know how to test the pilot jet. Turning the mix screw closed has no effect until 1/8 turn.

This is much different from the experience at 40 degrees. The pilot was perfect for the cold.

I will figure this out an have it running good. I just need to get used to the fact that this carb is so literal and not a Holley or a Q- Jet.

  • Kenzo

Posted January 22, 2009 - 07:00 PM


okaaaaa.... :lol:

u have everything under control...i wus mistaken that u had been asking a few questions :banana:

i'm familar with The Glen...i'm a wannbe...here's a pic of me from the 2.9 mile roadcoarse at Texas World Speedway...i wus an advanced/instructor level before i got the crazy idea to open a restaurant :lol:

Posted Image

:lol:

  • HBLARRY

Posted January 22, 2009 - 10:23 PM


jlutty650l,
You've made a lot of nice modifications to your XR650L. I have used the Pig Pen's jetting and needle position charts and they have been very accurate for setting up my 2000 XR650R for the So. Cal mountains,baja, high deserts and Death Valley even below sea Level. It has the hop up kit installed
(68S pilot, B53E needle,needle jet, and 175 main jet). The performance change from stock is, for no better word.....explosive.

Why anyone would want to put in the full HRC kit with the 11.5 to 1 forged piston, cam, tensioner and the other bells and whistles is way beyond me. Mine needs soft hands on the throttle or your going 90+ mph real quick and you can probably do that all day.

http://world.honda.c..._kit/index.html

What I didn't see listed in your modifications was the 10.5 compression "L" piston, bigger valves or springs. For those mods and big jetting to work properly you need the compression and increased flow volume. With a stock "L" compression ratio of 8.5 to 1, it's probably going to be somewhere between 165 and 170 on the main jet. If you've got the compression....you need an "E ticket" to the dyno or a dry, flat straight road to run a 100mph
on. The "R" runs equally fast on the 168 and 172 also.

I've ridden my son's 2003 "L" with all the Dave's carb mods and it by no means performs like my "R". Honda's got it pegged right out if the box.
We're on the trial and error program. I think the intent here is to get the Kehin 40mm carb to develop some of the needed low end torque and mid range and let the final gearing take care of the top end.

Kenzo's done a great job getting this dialed in. A lot of performance for the
dollars spent and hopefully just as dependable as the XR650R.

Hope to hear more on your bikes performance.

Dyno time anybody ??

HBLARRY

  • jlutty650l

Posted January 23, 2009 - 07:20 AM


okaaaaa.... :lol:

u have everything under control...i wus mistaken that u had been asking a few questions :banana:

i'm familar with The Glen...i'm a wannbe...here's a pic of me from the 2.9 mile roadcoarse at Texas World Speedway...i wus an advanced/instructor level before i got the crazy idea to open a restaurant :lol:

Posted Image

:lol:


So Kenzo is a business owner, too? Good stuff. Do you serve wine at your restaurant? I'd love to see the wine list. Is it on line? Got any Texas wines on there? You should carry them if you can.

I got into the bike hobby because I own a business and cannot justify the car hobby for a little while. So far, I am on my 3rd Honda. This one is my favorite.

Hey, I don't see anywhere on this and one other site I used to hang out on where anyone has tried this combo on an L. I am just starting to get a handle on this carb and am pressed for time every time I touch the bike. I am trying to guess on alot of stuff and drawing from documented experience where I can find it.

I will have this ironed out by Spring. After I go to four conventions over the next 6 weeks, I might have more time to install a few different jets and really nail down what effect the net of the airbox, filter, R carb, porting, Stage 1 cam, XRO header, WBE2 muffler have as a whole.

Even running at about 90%, this is already enough to get me in trouble.

  • jlutty650l

Posted January 23, 2009 - 07:35 AM


jlutty650l,
You've made a lot of nice modifications to your XR650L. I have used the Pig Pen's jetting and needle position charts and they have been very accurate for setting up my 2000 XR650R for the So. Cal mountains,baja, high deserts and Death Valley even below sea Level. It has the hop up kit installed
(68S pilot, B53E needle,needle jet, and 175 main jet). The performance change from stock is, for no better word.....explosive.

Hope to hear more on your bikes performance.

Dyno time anybody ??

HBLARRY


Thank you!!! I would love to dyno it. There is a shop here in Springfield, MO where I can swap jets and needle positions all day. All it takes is money and time. Both are at a premium for the rest of this month. Customer entertainment and travel tend to chew on the toy budget this time of year.

I leave Monday for the first trade show of the season. Family is coming in tonight to stay with the babies while we are in SAC. Gun show in AM. The L is gonna have to wait.

After getting some sleep last night, my gut tells me I should try the 68s and hope it goes out to two turns so I have room for colder and hotter weather adjusting.

The main will have to be proven on the dyno.

  • HBLARRY

Posted January 23, 2009 - 12:42 PM


i wus an advanced/instructor level before i got the crazy idea to open a restaurant :lol:


Is this restaurant something a guy like me, an everyday Joe, would see featured on Diners, Drive-ins and Dives. Please tell me it's fine Texas BBQ.......:banana: Guy Fiery is an eatin' fool, my kind of hombre.

Too bad he doesn't park that Camaro and start riding a bike to these joints.

The best thing about riding around on a motorcycle is headin' to the FOOD. :lol:

Oh........somebody needs to dyno this carb set up eventually...........

HBLARRY

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Kenzo

Posted January 23, 2009 - 01:33 PM


Is this restaurant something a guy like me, an everyday Joe, would see featured on Diners, Drive-ins and Dives. Please tell me it's fine Texas BBQ.......:lol: Guy Fiery is an eatin' fool, my kind of hombre.

Too bad he doesn't park that Camaro and start riding a bike to these joints.

The best thing about riding around on a motorcycle is headin' to the FOOD. :lol:

Oh........somebody needs to dyno this carb set up eventually...........

HBLARRY


the carb itself wud be lucky to add 1-2HP peak...hard to tell how much it fattens the curve but it sure feels gud :banana: :lol:

Seafood Restaurant, Oyster Bar & Grill...

:p

P.S. better keep it on topic...i hear MF still lurks around here :p

P.S.S. probably starting boiled crawfish next weekend :p

  • HBLARRY

Posted January 23, 2009 - 03:45 PM


I think your right about the actual 1-2 HP increase over stock.
Edelbrock is advertising 37.4 HP @ 5500 with an acellerator pump carb
and it starts to taper off real quick after that. Maybe 3+ HP.

I'm having a little trouble posting pictures. Photobucket is uploading
only one half of the image from my computer. File's probably too large.
Never has been a problem in the past. I noticed you've been able to
post some nice large images. I'll keep messin' with it.

HBLARRY

  • jlutty650l

Posted January 25, 2009 - 09:58 PM


Oh........somebody needs to dyno this carb set up eventually...........

HBLARRY


I know. Too bad we didn't have a stock L to run as- is, Then do stock internals, uncorked w/ Dave's Mods "L" to swap just the "R" carb on for a test.

  • HBLARRY

Posted January 26, 2009 - 08:34 AM


I would have thought that someone or Honda might
have done the stock "L" already........

Changing the needle position and needle jet on the "R" Keihin Carb
is a bit of a pain the first time you do it. This carburetor uses
some really soft metal screws and they get deformed easily so
you need a good fitting screwdriver and some patience.

The screws that retain the needle jet in the slide are a
little tricky to get in place, so extra care should be taken there
Make sure the little spring on the slide hinge is seated all the way,
it came off on me once. I think that was my own doing but it
hung up the slide. It's never happened again.

The main and pilot are relatively easy changes.

I like the simplicity of the carburetor and it works dependably.
It would be nice to pass along the optimum jetting for sea
level and just ride the beast.

HBLARRY

  • Kawidad

Posted January 26, 2009 - 09:30 AM


Well, I too took the plunge and did the conversion. :lol:

Several comments:

Wow, what a Bee-otch to get that R carb mounted in there. It fits, but just barely. I dread the thought of removing it.:lol:

The throttle cables are too short, but are manageable. However, the throttle housing is a pain. It just does really fit with the factory switch housing. I moved the switch housing to the inside of the brake cylinder, but I may have to ghetto up something.:lol:

Now, as to how it runs: It runs much better. Is it night and day? No, but it is noticeably better. The jetting is close, but needs to be fine tuned. I forgot to check which needle, but it is a 165/65S with the needle in the middle. I think the pilot needs to be a 68, but otherwise seems pretty good. (Bike is stock with the Dave's air box mod and a Supertrapp pipe):p

In the end, is it worth it? I think so, but until the jetting is right, the jury is still sort of out. However, the throttle response is much improved even as is, so all in all I too would recommend it. :banana:

  • Kenzo

Posted January 26, 2009 - 10:04 AM


Well, I too took the plunge and did the conversion. :lol:

Several comments:

Wow, what a Bee-otch to get that R carb mounted in there. It fits, but just barely. I dread the thought of removing it.:p

The throttle cables are too short, but are manageable. However, the throttle housing is a pain. It just does really fit with the factory switch housing. I moved the switch housing to the inside of the brake cylinder, but I may have to ghetto up something.:lol:

Now, as to how it runs: It runs much better. Is it night and day? No, but it is noticeably better. The jetting is close, but needs to be fine tuned. I forgot to check which needle, but it is a 165/65S with the needle in the middle. I think the pilot needs to be a 68, but otherwise seems pretty good. (Bike is stock with the Dave's air box mod and a Supertrapp pipe):lol:

In the end, is it worth it? I think so, but until the jetting is right, the jury is still sort of out. However, the throttle response is much improved even as is, so all in all I too would recommend it. :banana:


it gets easier to mount after the first time :p

i'm probably gunna do the 68s even though the 65s tests correctly...i have to turn the idle screw up one full turn and use the choke for cold starts then turn down the idle once warmed up...probably do the HRC needle the same time...

...with the stock needle i have it on the lowest/richest clip position.

:p

  • Kawidad

Posted January 26, 2009 - 03:13 PM


it gets easier to mount after the first time :lol:

i'm probably gunna do the 68s even though the 65s tests correctly...i have to turn the idle screw up one full turn and use the choke for cold starts then turn down the idle once warmed up...probably do the HRC needle the same time...

...with the stock needle i have it on the lowest/richest clip position.

:banana:


So where would that put the idle mixture screw at?

  • Kenzo

Posted January 26, 2009 - 05:11 PM


So where would that put the idle mixture screw at?


the idle i set at wut i think is ~1400rpm...after warmed up.

...i run the fuel screw is out 2 1/4 turns to reduce "burbling" on decel...if i turn it in all the way in it stumbles almost to the point of dying...smoothes out at about 1 1/2 turns.


:banana:

  • Kawidad

Posted January 27, 2009 - 12:19 PM


the idle i set at wut i think is ~1400rpm...after warmed up.

...i run the fuel screw is out 2 1/4 turns to reduce "burbling" on decel...if i turn it in all the way in it stumbles almost to the point of dying...smoothes out at about 1 1/2 turns.


:lol:


Thanks, I'll try that and see what happens.:banana:

  • Kawidad

Posted February 01, 2009 - 09:41 AM


I took the bike to my buddy who is a former race tuner and local indy, to have him take a spin and see what he thought of the jetting. He thought it was pretty close at what it is. Maybe one notch on the needle richer, but otherwise he suggested to just leave it alone. Personally, I think the needle area is okay, it just lean pops on decel. I haven't made up my mind yet on the #68 pilot jet.

I'm going to take one of the throttle cables into his shop and have a look see and see if I can find a longer cable that will work.





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