carb tuning

[vmax1125]

hey all i just got done with a morleys jet kit and need to fine tune it. it runs real sluggish and feels like only two cyl are kicking until it hits 7 grand then it launches. i asked sean and he said it sounds like it needs some needle shimming. can anyone give me some guidance on the shimming how much? sean told me to run the 160 jets he said it may be a tad rich but acceptable.
i have not synced the carbs i need to get my hands on a carbtune and i set the a/f screws 3 turns out. also i dont have any shims sean said radio shack or lowes but i am concerned about them being the same thickness.
any help would be appreciated
Chris :th_help:

 

[maleko89]

Chris, sync your carbs for sure. It will be off since you remove carbs to change main jets. You can get precision shims from Paul C. Check out the VMF Links page under Precision Shims. Another route would be to try #4 finishing washers. Use a caliper to make sure thicknesses are the same.

 

[vmax1125]

Mark, thanks for the heads up on the washer size went in search and found some at lowes #4 size i bought a few bags i figured sizes would vary but i found 0.030 to be most common so that what i used. it did help but it is still sluggish from start to 6 grand and when cruising at 4 grand it surges a bit like two are hitting and the other are trying to go. i did also tinker with the sasy i noticed when its set at 1800 its worse but improves when set at 3000 or better. i did search for a carb tuner today but no luck i think they really need synced before i start tuning more any thoughts? anyone? please?
Chris :ummm:

 

[Akatora]

Hello,

Have you checked the condition of your spark plugs?

It is possible that a little bit rich adjustment will cause them to get dirty quite quickly, and drop one or two cylinders away. This is enough to give that kind of lazy feeling with occasional hiccups. This is naturally easy to test by changing the plugs or maybe cleaning the old ones.


Regards,

AT

 

[4gasem]

You REALLY need to sync it up. I have a slight stumble at about 7000 rpm's when the sasy is set to 6000 RPM but at 4500 it's gone completely.

If I spaced the needles one more time it would be perfect I think.

I'm running 157.5

 

[vmax1125]

i have not checked the plugs yet i am waiting for sean to email me and get his input. i know the carbs need synced it was stumbly of the line bone stock so i know they didnt get better with the removal and jet kit i am ordering a morgan tonight. i am waiting for some input on my fork project so i can get them back together i think i have it but want to be sure thats my main problem at hand so if anyone with some fork lowering exp. would chime in the fork lowering thread i would greatly appeciate it. :worthy:

 

[vmax1125]

quick update took a few minutes and poped out the plugs and they look very clean tips golden brown and white porcelain does not seem rich at all.
Chris :confused2:

 

[maxcruiser]

Hey Chris, I think your best bet is to follow Sean's instructions on setting up the carbs - I am sure he can get them right for you.

Mike

 

[vmax1125]

i received my carbtune pro a few days ago them guys are fast 5 days at my door . i synced the carbs tonight they were out a little but got them bang on very easy with the morgan. it made a big difference in low and mid range but it still dont have it yet and i get an occasional spit from the carbs. Sean recommended some more needle shimming and maybe swap back to stock springs. i have .030 shim in there now does anyone know what the adjustable needle spacing is from slot to slot or overall from top to bottom. i only have .030 washers right now and .060 seems to be alot thats why the question about the adjustment range of the needles.
Chris :ummm:

 

[maleko89]

Chris, 1 clip is approximately .026 inches.

To get my midrange right with stock needles I put Mikuni 165's in there. Top end was rich and still a slight stumble at 6K. I put 1.25 clip shims under the needle and that worked well. Try shimming your needles 1.25 clips. That's about .033 inches.

 

[vmax1125]

i just put the stock springs in and changed the .030 shim with a .036. i also set the mixture screws 3.5 turns out. i give it a test run and it keeps making progress it even run good with the sasy set low. it has to be real close just a bit more on the low end i dont know if i should keep tuning or try to get it to a dyno. any opinions? chris :confused2:

 

[maleko89]

I'd get on the dyno and see where you're at. You won't get the same low end you had with stock. With Morley's air box you loose a bit of intake velocity which helps low end. If you spend most time down there it might be worth going back to stock air box. I love the great midrange and screaming top end so I was willing to sacrice a bit of low end. IMHO.

 

[vmax1125]

i am with you mark i like the rrrr's i'll get on the dyno asap and take it from there. thanks for the input , Chris