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Workshop => Carburetor, Intake, and Exhaust => Topic started by: DOUGLAS on August 13, 2018, 07:05:15 PM

Title: Carb Alignment with Big Bore Cylinder
Post by: DOUGLAS on August 13, 2018, 07:05:15 PM
was able to get some time on my bike today. having a big bore cylinder in a OEM frame I did not like my options with the alignment of the carb to the intake. the top of the carb hits the frame making it extremely difficult to install and to service the carb. trying stock OEM cr250 and UPC intakes the out come was all the same poor alignment. I picked up an aluminum billet one from atvguy and this was the closest one but still did not like the way it fit. I mocked up an intake. time to send it out to fab shop.

Title: Re: CARB ALIGNMENT
Post by: hickwheeler on August 13, 2018, 07:09:38 PM
I'm not having those alignment issues. I'll get you a pick to night
Title: Re: CARB ALIGNMENT
Post by: DOUGLAS on August 13, 2018, 07:55:22 PM
do you have a 350 esr cylinder in a stock frame running an led intake ?
Title: Re: CARB ALIGNMENT
Post by: DOUGLAS on August 13, 2018, 07:56:14 PM
and 1/4 spacer plate ?
Title: Re: CARB ALIGNMENT
Post by: hickwheeler on August 13, 2018, 08:13:27 PM
I have pro cross cylinder vf2 reeds with a stretch stock intake and a stock air intake with JL airbox eliminator
Title: Re: CARB ALIGNMENT
Post by: havinnoj on August 14, 2018, 01:26:25 AM
Glad you got it sorted Doug. Out of curiosity, did you have any issues without the spacer?
Title: Re: CARB ALIGNMENT
Post by: DOUGLAS on August 14, 2018, 05:52:38 AM
without the spacer the alignment is still not good but useable. the spacer keeps the petals from touching the cylinder causing premature wearing. using the spacer throughs the alignment out more. as you can see in the pics. using different intakes does not clear this up on a stock frame. changing the angle pitching it down to a 30 degree is the best option for me. it also gives room at the top of the carb to remove the top to change cable and service carb.  i'm sending out my draft to the fab shop this week. 
Title: Re: CARB ALIGNMENT
Post by: jcs003 on August 14, 2018, 10:49:54 AM
short body carb, or a 35mm carb bored out.  just a thought.
Title: Re: CARB ALIGNMENT
Post by: havinnoj on August 14, 2018, 11:46:32 AM
Wow, that's pretty extreme, didn't know the ESR cylinder intake angle was that changed from some of the others.
Title: Re: CARB ALIGNMENT
Post by: DOUGLAS on August 14, 2018, 11:58:11 AM
short body carb, or a 35mm carb bored out.  just a thought.
I already have a 38 that Arlen suggested to run. he built the motor so i'm going to follow his advice. I did think of also getting a short body.  I also had it polished. waiting for its return from Race Reflections. thanks for your thoughts on this.
Title: Re: CARB ALIGNMENT
Post by: jcs003 on August 14, 2018, 12:07:17 PM
just to clarify.  a 35mm has is smaller altogether and should rectify your fitment issues.  If it is then bored, it will compensate for the lack of flow you need with the big bore.
Title: Re: CARB ALIGNMENT
Post by: F-Red on August 14, 2018, 12:41:24 PM
UPC intakes the out come was all the same poor alignment.

Doug,

That is some serious misalignment.  :o I have the same cylinder and carb. I'm running ESR's intake with a UPP manifold. Mine was a little tight, nothing like yours.

What is a UPC intake? Typo?

Title: Re: CARB ALIGNMENT
Post by: 2Nubs on August 14, 2018, 01:51:12 PM
My boot between the carb and filter lightly rubs the frame, but I don't have the carb interference you have.

I also have an ESR cylinder and 39mm PWK using a factory intake. Curious of what the variable is here.
Title: Re: CARB ALIGNMENT
Post by: DOUGLAS on August 14, 2018, 01:57:35 PM
UPC intakes the out come was all the same poor alignment.

Doug,

That is some serious misalignment.  :o I have the same cylinder and carb. I'm running ESR's intake with a UPP manifold. Mine was a little tight, nothing like yours.

What is a UPC intake? Typo?


  yup its UPP typo.
Title: Re: CARB ALIGNMENT
Post by: Hawaiiysr on August 14, 2018, 02:17:15 PM
i have the same issues with a stock frame, stock cylinder, cr manifold, AS 38mm and a eliminator. i think a upp will fix my issues but i also want to install a JL bracket. i still have to play around with it all. not enough time in a day