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Re: Dave's Carb Mods

Posted: Sun Nov 25, 2018 9:51 am
by davisjj
"Is this the airbox snorkel the post mentions removing?"

Sorry for the above post. I tried to attach a photo but wasn't able to.

Re: Dave's Carb Mods

Posted: Sun Nov 25, 2018 10:59 am
by JoeRC51
It's under the seat and restricts the airbox opening. Drill out the two rivets with an 1/8'' drill bit.

Re: Dave's Carb Mods

Posted: Sat Jan 12, 2019 12:11 am
by Pipeburn1967
I am wondering if anyone has seemed to have a weak spring ? I did the Dave's mod and used 158 main and I found a #55 pilot that was the longer type,I did file the slosh baffle to accommodate height but when I reasemblemed and turn the cable mechanism by hand it seems my slide don't return all way down,any suggestions??. Thank you, I thought about stretching spring out a little to give it more spring.??

Re: Dave's Carb Mods

Posted: Sat Jan 12, 2019 9:20 am
by JoeRC51
The slide isn't supposed to close completely and you sure as hell don't want to stretch the spring.

Re: Dave's Carb Mods

Posted: Sat Mar 30, 2019 11:03 am
by MrDion
Hello, Thanks for all the info. I have a new 2016 XR650l which now has 1000 miles on it. The bike really needs help with hesitation while turning the throttle. Turn it slow and the bike responds well. Crack the throttle fast and the bike sputters, like when you shift to second gear, twist to wheelie but it just sputters.
I need a little more info on the washer Dave's Mod denotes. I followed the link to JetsRUs, thanks for that, but the washers there are listed as 2.0-3.0 in size while the instructions state 0.02-0.03. Can you clarify please.

Another thing is jetting for altitude. I live in Colorado at 7800' and ride up and down the mountains at or around 6000' to 8000'. How should I jet? or what size jets would you recommend, Main jet and pilot or slow jet. I did see the mention about Denver, 52 pilot and 158 main. Was thinking of starting there but that's also what was recommended for sea level?
Thanks for helping us laypersons to push past our fear of carburetors.

Re: Dave's Carb Mods

Posted: Sat Mar 30, 2019 12:27 pm
by JoeRC51
At your altitude the stock jetting should be pretty close , the bog is just the nature of the stock constant velocity carb.

Re: Dave's Carb Mods

Posted: Sat Mar 30, 2019 6:20 pm
by MrDion
Thanks for the reply. So should I do the Dave's Mods and leave the jets as is or NOT do the Dave's Mods? What do you think of the "Flat Slide" carb I see on xrsonly?
Mods to date:
Smog delete
snorkle deleted
gearing 14-48
Rehthal bars 971
IMS foot pegs

soon to add
Uni filter
Dunlop D606
Clark 4.0 gal tank

Re: Dave's Carb Mods

Posted: Sat Mar 30, 2019 7:12 pm
by JoeRC51
In your case I would just drill the slide's vacuum holes. Steer clear of ''XRs Eventually'' , they're not known for their customer service. Niche Cycle has the best prices on the Mikuni TM40 pumper carbs and the cables , adapters from Amazon. The ''kits'' are higher priced than the individual parts add up to. The Keihin FCR is over priced and more difficult to tune.

Re: Dave's Carb Mods

Posted: Sat Mar 30, 2019 8:10 pm
by MrDion
I'll drill the slide's vacuum holes and report back on the out come. Just looking to get it to run the best it can here in the mountains.