XR650L Smog Block-Off Carb Pics

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XR650L Smog Block-Off Carb Pics

Post by 4Strokes » Fri May 20, 2016 11:55 am

Topic: XR650L Smog Block-Off Carb Pics
Author: KingTutt
Posted: 01/11/2005 1:02:17 PM

Installed IMS smog block-off kit. It's a little confussing at first with all the hoses but is acually quite simple and easy. Instructions with block-off kit left many unanswered questions. After much research in these forums, I proceeded as follows. The kit includes 4 vacuum nipple plugs but I only used 2. The nipple on right side of carb (same side as choke insert port) and nipple at very bottom are vent/drain ports and were left unplugged using existing vent tubing. The front (outlet or cylinder head side) of carb has 3 vacuum nipples. (California model) 2 on top pointing up and one near the bottom pointing down. I plugged the one near bottom pointing down and the right side (closest to choke insert port). I routed hose from the upper nipple closest to throttle linkage to the vacuum diaphram on left carb side behind throttle linkage. Rubber plug included in kit is for the airbox bottom. I then removed small carb vacume diaphram mounted on frame. Charcoal canister between crankcase and airbox should be left as is. (If using a Clarke or similar a/m gas tank, this breather canister will need to be mounted on the lower mount tab on frame where carb vacume diaphram was to make room for petcock) Carb vent hoses should not be changed. Route the vent hose that runs off the "Y" that used to go to vacume diaphram on frame to under the seat.
1. CaliforniaCarbFront.jpg
2. CarbRightSide.jpg
3. CarbLeft.jpg
4. CarbComplete.jpg
5. (Case breather pic removed)
6. 6Gearbox2Airbox.jpg - Charcoal canister is optional, but not nessesary!
7. 7Hose2AirboxTop.jpg
Disregard pics of case breather as I found out it was incorrect. After seeing a bike set up by a Team Honda machanic, I realized the vacuum canister should be installed between airbox top and case. Se pics in link for correct placement...

Reply by cracked junior on 03/07/2005 6:04:30 PM
i have one question. doesnt relate to smog pump. was gonna ask this in different forum but such a good picture of it in number 6 why is the shock spring yellow? why not something that goes with the bike? Jeremy

Reply by doubleodevine on 03/07/2005 8:38:11 PM
that's just something that its just the way it is. many times on a car, the coilover is red, blue, yellow, or whatever else the manufacturer made it. its like why are inverted shocks brass colored when the rest of the bike is the manufacturer's color? like i said it must be something that is how it is.

Reply by dave_cl on 03/08/2005 08:47:51 AM
There looks to ba an extra hose nipple on the carb- is that a california carb? Dave

Reply by KingTutt on 03/08/2005 10:55:31 AM
Yes, California. There were 2 vac nips on the top front and 1 vac nip on the bottom front (not shown in pics) and the vac diaphram on the right side. I plugged top right and bottom, connected top left to diaphram.

Reply by CrashDBad on 04/10/2005 11:40:42 PM
dave_cl and XRnTahoe, you guys rock. I just finnished up the carb mods and IMS smog kit. I have not yet had a chance to see how she runs; I've been laid up with a torn mcl after a nasty crash last month. Thanks for taking the time to post these instructions. XR, those pics saved me from utter confusion on install. I went with daves jet sizes and pulled the snorkel on the airbox. I haven't bought an air filter yet and was wondering if a foam type filter will make much of a difference. Anyy brands you guys like? Any thoughts on drilling out the stock exhaust a bit? Rick

Reply by dave_cl on 04/11/2005 03:59:05 AM
CDB, the foam should flow a bit better. Before drilling the exhaust, pull nthe 2 8mm-head bolts and grind the welds to pull the baffle. Its a lot quieter than an aftermarket exhaust, but still seems loud to me. Dave

Reply by KingTutt on 04/11/2005 2:52:36 PM
Rick, the 2 most popular brands are K&N and Uni. Either one would be a good choice however, allthough the Uni costs half as much as the K&N, it is very easy to over oil and is hard to get it to sit right in the airbox.

Reply by Totte_S on 09/07/2005 11:43:34 AM
Hello there. 1:st time here. I live in Sweden and have got a NX650 -91 (also known as Dominator, wich has same enginge as the xr650 L, if you didn't know this)

I've tried to remove smog shit, with help from the articles here at 4Strokes.com, but i wont work. The bike runs really really bad, if it starts at all. Something must have been wrong. Please try to give me a hand figure it out, i'm not interested in mounting the crap back. When I start it up, it runs bad and only at low revs, with a little throttle it might rev up to appr. 3000rpm, but then i suddenly "snaps" and dies. The "snap" sounds like an airsound, the sound of highly compressed air that very quick finds a way out. Sounds almost like an airgun. I've tried to adjust the mixture screw, but the engine drops dead to fast. Where do i start looking for errors? To much air or gas? Wrong mounted hoses on carb? The carb is Jetted with 58/155 keihin jets, snorkel removed, the rest is stock. The bike ran OK before, the rejetting was needed after the snorkel was removed.

Reply by Hardcharger on 09/07/2005 1:53:47 PM
How many turns out is the pilot screw now? If you don't know start it at 2.5 out from lightly seated.

It sounds like either you've got a vacuum line capped off incorrectly on the carb, or one of the vacuum lines is cross-connected or even disconnected. I'm assuming you have the manufacturer's smog block-off instructions. If not, you might do an internet search for "IMS XR650L smog block-off" and see what turns up.

Try to use the photos in this thread as a guide. Of course without seeing photos of your current set up it'll be hard to tell you what might be wrong. Good luck, HC

Reply by Bustamove on 09/07/2005 8:20:00 PM
OOPS??? I removed the canister behind the smog pump as well, Should I put it back?? If not, could I damage the engine??

Reply by Hardcharger on 09/07/2005 9:26:22 PM
Nah, the black canister removal is part of the complete emissions equipment purging process. Just make sure to have routed the crankcase breather hose directly into the airbox to keep the system closed or sealed, per the kit's instructions. Keep Ridin' HC

Reply by Totte_S on 09/08/2005 12:45:12 AM
Pilot screw 2 1/4 turn out. I've made my own kit, got no instructions, except the one on 4strokes. Maybe someone can give me a link to information about how the carb and the smog block works together, so I can figure out what's wrong from that? I'll check out the vacuum line routing tonight. (GMT +1)

Reply by Hardcharger on 09/08/2005 09:38:04 AM
Here's what I've found on this site which you might already have found yourself. Tech Article: XR650L Smog & Oil Separator Removal. Good luck & keep us posted, HC

Reply by Totte_S on 09/16/2005 02:40:09 AM
Thank's for all input. I've solved the problem so far. It seems like the vacuum-hose on the carb wasn't tight enough, and in combination with the fact i was running out of gas it made the snapping air-sound. When i turned over to spare and strapped the hoses up,everything worked fine. Took a piece of metal, some tools and made my own plates for covering the holes in the cyl. So far so good. Now having other troubles, but that's Off Topic in this subject.

Reply by Jlutty650L on 12/18/2005 12:27:34 PM
Thanks XRnTahoe (Temecula). I used the pix today!!!

Reply by KingTutt on 12/18/2005 1:27:16 PM
You're welcome. After completeing my bike, I did my buddies '05 XRL, (see dualing carb mod pics in galery) I realized That the large charcoal canister can be left alone. But if you go with the Clarke 4.7, it will need to be moved to the lower frame mount. (again, see pics) Before I knew this, I removed it completely, then I had idling problems I think because the case vent hose was going directly to the airbox. (too much vacuum to the case breather-although there are some who have no problems with that set-up)When I re-installed the canister I cut hoses to fit not realizing they were already perfect because I didn't remember how they went on. Anyway, you may also have had a 3rd vent hose going up from a y fitting on the carb vent hoses. This is fine and can be routed out of the way. My pics show that 3rd hose removed.

Reply by phathead9771 on 12/20/2005 4:11:25 PM
Thanks for the information! It was really helpful. Quick question, I am in California also, California tanks have a vent hose. What did you do with it? I left mine hanging and now my whole garage smells like gas after a ride. I was considering ordering a non-California gas cap.

Reply by KingTutt on 12/21/2005 08:42:21 AM
phathead, check out my pics in the signature link. I used a left over piece of gas cap vent hose to run from gas cap to the hole in the triple clamp pivot bearing. That will solve that problem.

I just updated pics of XR650L carb after smog block-off. This is a California model carb so bikes from other states will have fewer vac nips to plug.

Reply by mitchner9g on 05/04/2006 10:30:31 PM
Gentlemen - Forgive my confusion please. I wish to clarify a self perceived contradiction between the "Dave's Mods" which at one time I thought were carved into some indellible material such as granite. If you read with me in unison of verse 17 of said text, you will note that the charcoal canister appears to be *entirely* removed from the XR650L:

"The trany vent is located just under the carb on top of the trany. Pull off the hose from the charcoal canister and smog pump, cut to length, and reattach. The hose will run between the trany vent and airbox."

These instructions indicate from mine eyes that a hose (harvested from another removed section of smog scuba gear) shall route from the crank case nipple to the lower input port of the machine's air box.

And the congregation said in unison: AMEN. Though, some hushed whispering doubtlessly ensues about the risk of oil vapor reaching our beloved machine's input tract, not to forget the consequences of air flow differences based on whether the cylinder is at TDC or BDC.

Here, our (my) much revered King Tutt offers an alternative take, which includes the charcoal cannister in the situation. I am in shock and awe! And here I will admit: My machine was bought in used condition and had all *but* the charcoal cannister removed in the emmissions debris removal process long before I took the helm. It is a California model, and I observed a configuration much like his above, with the charcoal cannister being fed from the crankcase, and it's top-most hose reaching to the top input vent of the airbox. But growing bitter with such an ugly contraption adding to all the other ugly contraptions of this bike, I boldly struck forth with a new piece of hosing! And in the spirit of Dave, jettisoned the charcoal cannister, and attached one end of the hose to the crank case nipple, and the other end to the lower input port of the air-box (which heretofore had been plugged with an improvised rubber device from previous anti-smog work). I then blocked off the upper input port of the airbox with another rubber widget procured at Kragen's auto supply.

But, now with inspection, i can say with utter certainty, that I should not have done so. For not only does the engine appear to be a bit softer around the edges, I do note residual oil along the walls of the input manifold of the airbox where the hose from the crank-case feeds.

I then read further in this forum recently from some other folk, (Hard Charger? Mr. Kubiack??? I cant recall right now) of another trick, where the hose from the crank-case is just terminated with a generic filter by the UniFilter corporation. I assume both of the input ports to the air-box are then plugged at this point. To me, this seems the most reasonable route: The removal of one last artifact of the emissions debris, while at the same time, affording your carburetor to breath only the air being sucked from the atmosphere, without any potent fumes coming from the bowels of the machine interfering.

Have I rattled on long enough?

Is this entirely too much?

Perhaps one too many pints of a mighty wonderful Lagunitas IPA tonight. I only rattle this off while modding my rear tail light assembly while the UniFilter is on order. Much fabrication using pop rivets and aluminum metal strips. Oh, I know now right off it won't be as tightly integrated as a mere *cast off* from "Old Guy's" garage but one must always try to aim higher than one intends to land. There I go again. By the way: Mr. Old Guy, your flat track project is nothing short of astonishing and I wish you nothing but happy riding!

Thanks for all the dialog, gentlemen. It has been most illuminating.

Reply by KingTutt on 05/05/2006 12:57:30 AM
mitchner9g, a very well written, well researched, whitty and interesting post I must say.

Strangly enough, today as I was installing the new Mikuni carb I found my bowl of spagetti connecting my airbox to the case breather via the charcoal canister had a vac leak somewhere. Rather than mess with trying to find exactly where, I yanked the canister and replaced it with a hose straight from breather nipple to the "top" inlet on the airbox.

I could see no reason why I should change the plug from the bottom to rout hose there, so I just routed it to the top using the hose already there and extending it down to the case with 1/2" fuel line and a handy plastic connector from NAPA.

I too am concerned about oil residue in the airbox though and would like to hear if you go with the little pod filter for case breather. My guess is that similar to a 1960's era Chevy V8, the case really needs no suction to remove vapor. Only an outlet so preessure doesn't build up. It's only because of smog and emmissions that those vapors were recycled through the combustion cycle.

Another funny thing (if it's funny to admit one's stupidity) the reason I left my canister on (or should I say re-installed it-OH, and I just thought of this or remembered it today)) was because after removing smog junk including canister, not really knowing what I was doing, (not firmiliar with the new Honda XR) my idle would go up and down strangely. Almost like I was holding the throttle for about 10 to 15 seconds, then let it off. Up for a while, then down for a while. I checked everything I could think of but was stumped as to the cause. I then inspected my cousin's '02 XR650L that was set up by a Honda race team mechanic friend of his. He had the canister. So I went back to re-install my canister thinking maybe somehow there was negative pressure building in the case and causing the weird idle.
Well, as I was taking it apart to re-configure, I realized I had connected the airbox drain tube to the lower airbox inlet and plugged the nipple where the drain tube connects. WHAT AN IDIOT!!!
Too many 's while wrenchin I guess. So, when I re-installed canister and corrected the stupid factor, my bike ran fine. I didn't realize that was the problem untill today for some reason. Perhaps a moment of clarity as I limmit my beer consumption to 1 or 2 now.

Anyway, as embarrassing as that story is, that's my story, and I'm stickin to it.

I guess I enjoyed your post so much I just had to share something special.

I'm sure HC, 4Stroken, 4Putter and the rest of the guys will be giving me a ration of crap for this one, but I just had to share my beer induced stupidity.

Let this be a lesson to ya kids, if it's more than a 6 pack job, you better have a case!

Reply by mitchner9g on 05/13/2006 6:51:06 PM
Yeah, all these vacuum hoses emanating from the carb do resemble spaghetti - Honestly, if I had done the original work on my bike, one of those lines surely would have ended up my nose for all I know :)

I don't have the machine in front of me now, but my recollection is that the vac-hoses leading from the carb (I'm running the Dave-ified stock Keihin) are currently draped downward and aft of the engine. Some are conjoined with a plastic "Y" tube. I will have to review this stuff with a clear head.

Anyway, when I get the pod filter installed on the crankcase hose, I will post a report on this thread.

I wanted to post an update as soon as i got a few pics uploaded here of my latest crankcase breather status. used a Uni Filter "Clamp On" type filter, part UP-103 (1/2"). in retrospect, i would have preferred a "Push-In" type (UP-123) for this application since i could have just pushed it into the crankcase breather hose and clamped it over the filter "nipple." alas, the "clamp on" type required another joint to connect the filter to the crank hose. perhaps a picture would help describe:
Here's a shot of the airbox ports getting blocked off:
you guys think it'll be okay? it seems to work, tho i do not like the "elbow" that i have joining the filter to the crankcase hose. would like to find something grippier, and at some point i'll want to fashion a bonnet around the filter so that it's not so exposed. but i'm at least relieved that i no longer have that crankcase hose feeding directly into the airbox input venturi! just holding my hand around the new crankcase filter shows that there is a lot of air movement caused by it; who knows how it was affecting carburetion. for sure the oil vapors were not doing much good, either.

Reply by mergoofmx on 01/14/2008 06:18:29 AM
Morning all, I am new to this site and I have been reading through the articles on XR mods. I have a FMX 650 which uses the same motor as the XR and I have done all the mods listed on this site, Smog removal, air box mod, carb mods........ i have done all the carb mods shown on this site and it has mad my bike far more powerful and more responsive but I have found that i am using a 240 main jet ! My dad had a lot of old main's in his spares from years ago so I experimented with them from 165+ to current 250. The 250 ran a bit rich when I did a plug chop so I went back to the 240. My question is as follows, has anyone EVER used such a large main like I have? The Dynojet mains are around 165 so why am I finding a 240 to be the best for me? Odd !!! Regards, Mat

Reply by dave_cl on 01/21/2008 5:47:07 PM
Doesn't sound like it. Maybe some other part of the main passage is blocked? What size jet was in there stock? Dave

Reply by mergoofmx on 01/22/2008 2:58:42 PM
Hi, Yeh Std it was 155 i think, it may have been 160 but it was really choked up, i have done quite a lot of mods and ran jets from std upto 250 and 240 was the best both performance and burn after a plug chop. regards, mat

Reply by dave_cl on 01/25/2008 5:20:47 PM
All I can say is- that's bloody weird. if it runs good, don't mess with it!! Dave

Reply by sivan on 07/27/2008 10:16:42 PM
Hi all. Sorry for reviving an old thread. I bought my used XR650L with a UniFilter crank case breather installed. It gets oily after awhile around the breather. I'm suspecting that it's old and clogged. What is the normal operation of this filter's effect on the surrounding? How often does it need servicing? Thanks!

Reply by dave_cl on 10/05/2011 09:45:04 AM
Oh, and don't forget- the black thing near the petcock is not a charcoal canister, it's an oil separator. If you get rid of it you may get oil in the airbox or wherever you stick the little filter you put on the crankcase vent. Dave

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