Should I rework my Stock 40mm CV Carb with CVP stuff or swap to a Mikuni 42HSR?
#1
Should I rework my Stock 40mm CV Carb with CVP stuff or swap to a Mikuni 42HSR?
Ok guys I currently have a carb that only has about 4k miles on it but it is in need of a complete overhaul to be correct again as it has spent most of its life sitting with fuel in it. I recently was turned onto a company called CV Performance by a fella on this board.
This company CV Performance doesnt have a phone contact which kinda makes me nervous about buying from them as they dont seem to visit their forum to often, so if I have any buying, tech, or concern questions I dont feel like I have very good support regarding proper parts to buy or jetting baseline info to start with.
http://www.cv-performance.com/products/
Thanks Greenohawk!
Anyways, I am quite familiar with tuning carbs and dont mind a little bit of work to build a great CV carb. However I want my FXDX to be a strong runner and am wondering if I would be better off spending about $300 on a new Mikuni 42 HSR carb than the $150 in parts ( complete rubber parts overhaul, with upgraded goodies ) I want from CVP to resurrect my stock CV carb into acceptable service levels?
I already have the S&S 510 Geardrive Cams, Thunderheader, Screamin Eagle Intake, and plan on eventually goin to a High Compression 95 kit.
I want this bike to be a runner and dont want to spend any money twice so if this CV carb needs to be trash canned please say so.
Opinions greatly appreciated!!
EDIT......I would also like feedback on the S&S Super E carb kit, with intake, and air cleaner...BUMP
This company CV Performance doesnt have a phone contact which kinda makes me nervous about buying from them as they dont seem to visit their forum to often, so if I have any buying, tech, or concern questions I dont feel like I have very good support regarding proper parts to buy or jetting baseline info to start with.
http://www.cv-performance.com/products/
Thanks Greenohawk!
Anyways, I am quite familiar with tuning carbs and dont mind a little bit of work to build a great CV carb. However I want my FXDX to be a strong runner and am wondering if I would be better off spending about $300 on a new Mikuni 42 HSR carb than the $150 in parts ( complete rubber parts overhaul, with upgraded goodies ) I want from CVP to resurrect my stock CV carb into acceptable service levels?
I already have the S&S 510 Geardrive Cams, Thunderheader, Screamin Eagle Intake, and plan on eventually goin to a High Compression 95 kit.
I want this bike to be a runner and dont want to spend any money twice so if this CV carb needs to be trash canned please say so.
Opinions greatly appreciated!!
EDIT......I would also like feedback on the S&S Super E carb kit, with intake, and air cleaner...BUMP
Last edited by parts eeter; 03-12-2013 at 06:00 PM.
#2
#3
rebuild yours , buy a 46 and 48 pilot and a 195 and 200 main ( cost 15 bucks ) buy 2 #4 brass washers from ace ( .80 ) . id buy allen screws from ace to convert all your screws . check for rips in accelerator pump and diaphragm drill vacuum hole in slide to .120 to .125 .
i dont think youd spend more than 40 bucks and it will run great up to 100hp
i dont think youd spend more than 40 bucks and it will run great up to 100hp
#4
The 510 cams kick *** IMHO...I have them I'm my WideGlide.As far as high compression with those cams I'd think twice.Its recommended to not go over 9.7 I believe with those cams.Where the carburetor is concerned a properly jetted stock CV carb is good for up to 100 hp according to NHRS.My carb has been re-jetted and a thunderslide installed to match the cams and Thunderheader...it is a good solid hard running bike fo sho! As money permits I am planning on going with the 97" kit from NHRS.for now however it runs great!
#5
Thanks for the opinions fells, I was a tad concerned about going with a 10:5 comp 95" piston kit with such a small set of cams. I do however usually push the envelope on compression when building all of my engines though and go to the small side of the cam selections and always seem to end up happy with the results.
Sonny, I will remove my carb this weekend and have a look inside to see what all it needs, but I am fairly sure the float bowl gaskets, ap diaphragm, jets,float needle, are all gonna be trashed.
The PO had some fella tune the carb and made mention of a Sportster needle being in there, so I am wondering if he ever drilled the slide to compensate for the reduced vacuum of the Screamin Eagle Backplate and K&N Air Filter?
Does the stock slide spring work well with the Screamin Eagle Backplate, and Drilled Slide? I was told its too stiff by some people to allow full slide lift with an open air filter like I have. Of course its only what I was told and have no knowledge on this myself.
If I can save this carb for under $50 bux I would like to. I did find a very useful tech on the Mikuni HSR VS CV40 here.
http://nrhsperformance.com/tech_mikunivscv.shtml
Sonny, I will remove my carb this weekend and have a look inside to see what all it needs, but I am fairly sure the float bowl gaskets, ap diaphragm, jets,float needle, are all gonna be trashed.
The PO had some fella tune the carb and made mention of a Sportster needle being in there, so I am wondering if he ever drilled the slide to compensate for the reduced vacuum of the Screamin Eagle Backplate and K&N Air Filter?
Does the stock slide spring work well with the Screamin Eagle Backplate, and Drilled Slide? I was told its too stiff by some people to allow full slide lift with an open air filter like I have. Of course its only what I was told and have no knowledge on this myself.
If I can save this carb for under $50 bux I would like to. I did find a very useful tech on the Mikuni HSR VS CV40 here.
http://nrhsperformance.com/tech_mikunivscv.shtml
#6
ive been hot rodding cv carbs for 20 years , i dont like the sportster needle but thats just me . you have 2 choices on the spring , lighter spring or drill slide but not both with both you can get slide bounce . im running cv on my tc and forcewinder and it runs great and has full slide lift , ive also ran them with screaming eagle air filter kit and they run great . i doubt you need as many parts as you think , just be sure to blow out all orfices with carb cleaner
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#9
Just one thing to consider about swapping to an HSR42...
The stock CV carb is simple to tune, there really is only one set of pilot and main jets that are useful for stage-1 and even beyond that its only minor tweaks.
The range of adjustment on the HSR42 is much greater. The pilot and needle you need tends to vary more and I found I needed to swap out the main between summer and winter. I never felt the one I had was dialled in properly until I bought and used a wideband O2 meter to check the results. What I ended up with was nothing like the suggested settings from Mikuni.
So, if you do go the Mikuni route I'd suggest a dyno tune if you don't have access to an O2 meter.
The stock CV carb is simple to tune, there really is only one set of pilot and main jets that are useful for stage-1 and even beyond that its only minor tweaks.
The range of adjustment on the HSR42 is much greater. The pilot and needle you need tends to vary more and I found I needed to swap out the main between summer and winter. I never felt the one I had was dialled in properly until I bought and used a wideband O2 meter to check the results. What I ended up with was nothing like the suggested settings from Mikuni.
So, if you do go the Mikuni route I'd suggest a dyno tune if you don't have access to an O2 meter.
Last edited by Foxster; 06-09-2012 at 07:03 PM.
#10