More talk about my engine build and updates.

[jasonp]

As some of you may of read I got my 4 wheeler running and took it out for a good ride last weekend after my winter engine build project. I was trying to get it to idle right and it didn't want to start for **** and basically had the whole range of the carb jetted way to rich..
So I took the carb appart and found the pilot screw had broken off inside the carb body and was suck there. I had to drill it out with a mirco drill bit as every other form I tried didn't work. I also decided to drill out the nozzle for the accel pump as I was having problems with the engine bogging off idle with the throttle quickly opened.
I got all the parts today and got it all together. Run's great, had to run a bigger air jet as my pilot jet was to rich but after that it ran great. Starts right up and everything. The accel. pump nozzle works wonderful when cracking the throttle open fast.. The engine responds like mad. Only problem now is in the mid range it's got this huge stumble when opening the throttle slowly, even when I tune the accel pump timing to be really short then my quick throttle response goes a way and I still have a bog. So yeah I ****** up there. Luckly I got a new nozzle just in case this happen.
So I got it jetted on the main very close now and it just pulls like crazy. Much more then before. It goes to show if your off on your jetting there is a lot of power your missing out on.
I found out that jetting main has no effect on the needle jet which was suprising to me and I now know that I have to go all the way lean on it. I was a 2 clip from the top and it was breaking up on the top end with 1/2 to 3/4 throttle.

 

[dave76]

Jason Thats why I love the Edlebrock, you tune with the needle height, and thats only a twist away. The accelerator pump is a matter of turning a screw in or out, thats it. But glad to hear you got going pretty good.

 

[jasonp]

Dave if you only new how much ******* around I've done with this carb to get it set just right and even then it's still off a little here or there. It's really quite frustrating. I've always thought that since this carb is more senstive to changes or vaccum and what not that this carb would help me make more power.. . when in reality, I've led my self in a path of constant battle with this bitch. The best way to tune this carb would be to put this Fer on a dyno with a sniffer. I actually may just do that as there are a couple atv performance shops opening up around here. What's really worried me about the brock was that being lean in the middle and rich on top and not being able to change it?? Or somehthing like that because of only a couple of adjustments. I heard though if you roll on the throttle slow that the accel pump doesn't work.. which is something that I wish this carb did.

 

[jasonp]

Also isn't the brock a 32mmX34mm oval carb? I wonder how that flows in compare to a regular 36mm flat slide carb.

 

[yamarider]

I haven't had any issues with getting the carb tuned right due to there only being a few adjustments, edelbrock seems to have hit the nail directly on the head with this one. And yeah, the accelerator pump only works when you *** the throttle quick and the extra fuel is needed, if you just roll the throttle on the pump doesn't kick in.

I'm not sure about how the brock compares in raw flow figures, but just pure flow isn't absolutely everything. A smaller carb bore means more air velocity through it, and that helps to atomize the fuel better, getting a cleaner and more powerful burn. It seems that they designed it well enough that the increase in efficiency compensates for the small amount of restriction the smaller bore may have.

 

[dave76]

Also isn't the brock a 32mmX34mm oval carb? I wonder how that flows in compare to a regular 36mm flat slide carb.

I think it's actually 32x36, but thats only on the airflow side, the fuel air side is a true 36mm round.

 

[jasonp]

Doesn't this carb also use a flat slide needle for better fuel atomization? I really like how that accel pump works. Seems to me this is designed after an lectron carb and from what I've read about them has been nothing but great things. Also this is what one of the top engine builder uses for 300 ex's when they where big.
Smaller carb will give you more throttle response and give you more signal to the jet block.. also giving you more torque. . . The carb I have now uses a 115 main instead of a 145 stock! That goes to show how much more vaccum signal is being supplied to the jet blocks. If that's a better design or not I have no idea. I sure it's a little more accurate as far as fuel wise.

 

[dave76]

Uhmm I'm using a #21 needle. I think this was a Russel design which I do believe was based on the Lectron. Edelbrock bought the patent.

 

[jasonp]

dude... this carb sounds crazy! It's nice to not having to take anything appart to change a jet.?? It gets really old after a while, call me lazy. How do you adjust the needle?

 

[dave76]

You do need the gas tank out of the way, but otherwize you shut the bike off, push the throttle all the way and hold, and turn the little adjuster knob on top of the carb. Turning to the left leans it, turn to the right richens it. There is a total of 20 clicks all measured from rich to lean with 20 being the leanest and 1 being the richest.

 

[jasonp]

and that's it.. it adjust the whole mixture of throttle postions?

 

[dave76]

and that's it.. it adjust the whole mixture of throttle postions?

Yupers

 

[dave76]

Dude it was worth every penny of the $399 I payed.

 

[jasonp]

Wow... you've never been to rich on the top and and lean on the bottom or something?! God how does that work!!??

 

[jasonp]

******* AMAZING!!

 

[dave76]

I always have tan colored plugs which proves to me that the mixture is close perfect.

 

[yamarider]

If you remove that useless rubber flappy thing from under the gas tank you can actually access the needle height adjustment just by taking the seat off and reaching under the tank.

Jason, i'm not sure if you caught this or not, but the needle height primarily controls the idle up to 1/3 throttle. The upper ranges require that you change out the needle with a different size. That's quick and easy to do though, take the carb off, take the top cap off, and just a few turns of the screwdriver and you have the needle in your hand.

 

[dswwarrior350]

I still have the rubber thing and i can get to my carb adjustment on the top of mine, you just have to listen real close to hear the clicks and have someone hold the throttle for you, its nice to be able to adjust on the trail with no tools.

 

[yamarider]

DS, how do you reach in to adjust yours? I take the seat off and reach in from behind the gas tank, and can easily hold the throttle open with my left hand and turn the adjuster with my right hand. I can actually feel the clicks without concentrating on hearing a faint sound, and nobody has to hold the throttle open for me. I'm just trying to figure out why you'd need someone to hold it open for you. Maybe you should try pulling that rubber thing out, it's 100% pointless once that snorkel and airbox lid is removed anyways.

 

[jasonp]

Interesting so you still have to take the needle out if you find that you are running to lean/rich in that range. So the adjustment only effects 1/3 and lower throttle. mmm I'll have to read more about this for sure. Thanks! I'll tell with this carb I have on I can make jetting changes real easy with the main jet nut at the bottom of the carb.. changing the needle you have to pull the carb. But low side you can just do it by taking the air filter off and changing the air jet if you out of range... or just use the pilot screw. Still alot more to **** with. I thought it would be fun .. now it's becoming a hassle and cutting into my riding time. Ah well. I'll remember that for next time.