jwahrmund, on 08 February 2012 - 04:23 AM, said:

The hard twisting throttle sounds like the cables need to be lubed up and /or rerouted. Maybe the twist grip assembly needs to be cleaned and lubed.As for the little rubber plug to cover the small vacuum hole I used a piece of tire patch. To cut the plug I used a zerk fitting(grease fitting) for a car and put the threaded end on the rubber then hit it with a hammer to cut it out. I'm sure a leather punch would have worked but seeing I didn't have one I had to improvise. With the whole mod it shouldn't die anymore.

That's the crazy thing. They are lubed and more loose than girl on prom night. When the bike isnt running, the throttle is smooth as butter. But when it is running, that initial pull is a little tight.after that, it is the same as my CRF through the throttle pull. And yes, maybe i am also used to the FCR on the other Honda, but it seems it shouldnt be quite like this.

Either way, we will give this mod the full meal deal and call it good. I think my current jetting will be fine 160/58, but will cehck it after a longer run. Supposed to snow today, so not sure i will get out.

Love these old XRs. Easy to work on and simple. Would love to see the trail bikes go back to air cooled engines, but once they make 'improvements' they will never go back. Just my thoughts, but with more and more restrictions on places to ride, high costs for families to ride at most ORV parks and the high cost of shop time to fix modern bikes...i am not sure how much longer this sport/hobby will be around. I sure as hell hope i am just being pesismistic.

That initial tightness when you go to twist the throttle is I have
absolutely no doubt created by the extreme suction in those carbs.
That was exactly what mine was like before the mod. Bike not running everything
about the carb seemed fine. Start her up and the twist grip was hard to turn
and the throttle would not return to a nice steady idle without you blipping
it and even then it still held up sometimes.You can't do a half pie job
with the mod. Do the full job. Cover or put the rubber plug in that hole that
already has the small rubber washer in it (remove that one) and replace it
with your bicycle repair patch one. Do the full cover of the ACV diaphragm hole
with your paper gasket. You could also use a thin bit of copper fuel pipe to
cut the small rubber insert. Sharpen up the external end with a file and whack
the patch out using that and a hammer..cheap hole puncher..Gasket screw holes  
you'd burn out with the heated end of a smallish round file if you have no punch. You will definitely need to rejet down on the Pilot
Leave it the same and things will be way to rich.I could see black smoke coming out the muffler without the rejet down.Spark plug was also covered in black soot on inspection.Engine was literally drowning in too much gas and was also sounding as blubbery as a blubbery kid.,

Horri, on 07 February 2012 - 07:42 PM, said:

Were you able to test the 55 pilot yet? Just checking as I will be rejetting the pilot this weekend. We are about the same elevation and temp. so what works for you should be at the very least close (if not perfect) for me.

TBH ,,No I haven't. What I'll say is this. If I start my bike with the 55 and it
runs fine at idle,,isn't blubbery..and is blowing no black smoke or literally fuel..
it's good to go. It does all of those so it's fine. I may look at going down again
in the future if I check the plug and it's black or sooty. Apart from that the bike is good as is.

I'm sort of busy fixing and selling the 82 500 and fixing my sisters pc so haven't had time for real testing.

It idles..no black smoke,,no blubbering..Win.

Admittedly tonight I had time for beer,,We all need the odd break from reality.

Horri, on 09 February 2012 - 02:13 AM, said:

Sounds like you have a winner. I have all the jets down to a 58. We're very close in elevation and temp so I'll probably be making a trip to the shop for one more jet. I'll let you know how it turns out this weekend.

xr650r148w, on 09 February 2012 - 05:26 AM, said:

Wow, your going to go from a 68 to a 58? Mine isn't running that rich, maybe a 65 but I gotta mess with my pilot screw some before I do that. I'm still out 2.5 turns.

pb1963, on 09 February 2012 - 10:51 AM, said:

I know mine is rich but not sure how much so I got jets from 68 to 58 so I don't have to go back to the shop for more. Mine is a little blubbery if you try to hold it at a steady 1/16 to 1/8th throttle. I have no popping on deceleration at all.I'm doing rejetting of the pilot jet this weekend so I'll post results when I know something.

xr650r148w, on 03 February 2012 - 07:44 PM, said:

I'm sure your method works, but I'm not sure its all necessary. I got to test my way (plugging only the small hole in the back at about 7 o'clock) this last weekend when I went on a 40 mile ride out in the AZ desert. 30 of that was single track, mostly second gear stuff. Ran great, just need to mess with the pilot circuit some. I've still got a 68s in there and when I run the screw all the way in the bike keeps running, just an increase in the idle. So I think I need to go to a 65. Definately no hanging idle and more engine braking, which I like because you use less brakes that way.

See this is why people get confused..What hole at the back at 7 oclock.

The back of what the ACV??,, the back of the carb??

Stuff needs explaining correctly or we go through the entire mire of
rubbish we've already been through to get things correct. xr650r148ws explanation
and description of what to do is plain and simple. Not having a go at you it's
just we get half hearted explanations all the time around the net and they
just don't cut it. Anyway,,Glad the bikes running good,,as is mine after the mod.

Horri, on 14 February 2012 - 05:32 PM, said:

The hole underneath the rubber diaphram inside the ACV. You posted a picture of it. You are correct though, there is a lot of confussion/lack of information on this mod, that's why I posted this thread to begin with. xr650r148ws does give a good explanation of what he did which is good, I was just hestitant to go that far because if you read in Borynack's description of understanding the ACV, he said at that bottom of his write up,

"The big confusion comes from some of the first guys on some groups, getting my modification backwards and cutting off the tit to the diaphragm, cutting the air from the air jet off all the time making the bike run bad. There would be no air going to the pilot emulsion holes at anytime. Some did this and had to buy new diaphragms to fix it and are sour on any talk about the AJCV."

So my take is if you remove the spring and diaphram your doing just what he said not to!" Yes/No??

Who knows, maybe there is more than one way to make it work.

I think there's two ways to skin the cat. Your method of I assume just blocking the hole that the small rubber washer fits in???,,is that your method???.. and xr650r148ws explanation of blocking it with his bicycle repair patch and his/my use of the paper gasket as well. Maybe the paper gaskets not even required and you can just leave the ACV diaphragm and spring in there,,I don't know as I can't recall whether you actually took those bits out or not. I've removed both of them from the bike as well as the small rubber washer,,I haven't cut any nipple off or anything. The diaphragm, spring and small rubber washer are in a bag in my carb spares dept so I can use them again at some other time should I need to..

Ok,,I see what hole you're talking about now..kinda forgotten about that one.,So make that 3 possible ways of doing the job. I just think xr650r148ws is the easiest..There can be no confusion with it..Anyway we more or less know all of them work so I suppose whoever's about at the time can choose to describe whichever one they want as their preferred method..

Here is an update on my testing and tuning with the AJCV blocked.

I tried to set the pilot circuit again because I still had a slight rich spot just above idle, ended up with 1.5 turns out, still with a 68s pj. Friday I went through the AZ emissions to get my tags for the street, didn't pass. Back to the drawing board.

Saturday I went in and put the new B53E and needle jet that I bought. Someone told me that they can where over time. Put it back together and this seam to clear up the 1/16th blubbery throttle. Must have been warn. I then went back in and put a 65s pj in it, adjusted the pilot circuit out 2 turns. Went back down to the emissions and passed.

Came back home and put my 68s I think runs better than the 65s which seamed a bit lean on decelleration.

So with my testing so far, plug the one hole under the diaphram at about 7 o'clock, leave the hole in the cover, the spring and diaphram alone, adjust your pilot circuit and your good to go. Maybe my original hanging idle problem was due to the warn needle, I don't know. All I know is the bike runs great, the throttle response is crisp and clean and it shuts down when you close the throttle and the bike rips. Plus, I can get it to pass emissions! Gonna leave it plugged!

I used to have a hanging idle and found the throttle valve was sticking before I got my FCR-MX carb. I took it apart and buffed it with 2000 grit sandpaper and the internals of the carb where the throttle slides. Cleaned everything up with spray cleaner and put a light coat of grease and I didn't have a hanging idle problem but I did have to do this once or twice a year. When the engine is started the suction causes the throttle to bind more.

Gordon Bennett!!,,They worry about what's coming out of a motorcycle exhaust when their's very few in the actual system but everyone drives around in massive trucks with the dog in the back spewing 8 cylinders worth of emissions out of them. Some things just never make sense in the US,.,But yep,,you got to the Moon and beyond,,Sure as hell didn't do that by worrying about "e-missions'.."You're go Gene",,Roll complete Bob,,High altitude staging is a beautiful sight..Love it.

Horri, on 05 March 2012 - 11:58 AM, said:

There has been a bill in the AZ legislature for the last 3 years to exempt motorcycles...........hasn't went anywhere. Seems pretty stupid to me but at the same time I've got a street legal XR650R!