Hot Cams an Jetting?

[Ketch]

This is what is going on i have installed a hot cam stag 2 with a wiseco 11 to 1 piston 85mm [stock] power bong Q4 pipe stock
carb. I'm haveing problems getting it jetted correctly I have a flat spot in low to mid range an then it comes a live the jetting i'm running a 148 main and a 40 pilot and the plug is still black. What do i do with the needle the clip is one nock down from stock do i move it back up or down to get more air? Any succestion would be a big help. Thank you Jimmy:)

[Ex'r Marlin]

Originally posted by Ketch
i'm running a 148 main Correct me if I am wrong, but I would think for your set up that a 165 or 170 jet would be needed. As for your low to mid (pilot)..... I don't know the answer to that.

[ccole400EX]

You my be rich somewhere ot cause your plug to be black but on the top end where the main jet is most important i would guess you are real lean. I ran a 165 dyno jet in my stock carb with the modds i have done. Did you move the needle? I would richen that up to. Good luck and keep us posted on how she runs.

I was looking over your problems and think i need some more info to help you figure this out.

Since the various parts on the carb effect differnt throttle positions (half or full for ex) not so much the rpms let us know at what throttle opening is the problems happening.

Is this a new plug?

Tho the main jet seems a little small and may need to be uped a little the rich condition seems to be in the lower settings. Tell us if the flat spot is at all throttle points? Is it worse on 1/4 1/2 or full throttle?

Does it bog or just lack power?

Well just give up any info you think may help as this is a lot of trial and error unless we get someone who knows the "science" of carb jetting.

It can get tricky as ccole400ex pointed out that you could be rich in one circuit and lean in another with the plug showing the rich condition. I had something like this on mine where the pilot was set up too rich and the main (160) was too lean. Not only was plug showing ok to lean but the pipe was blowing carbon everywhere. using a 168 now and its seems all the circuits are getting along better, but may still be a little lean on the MJ.

Hope this helps

[Ketch]

Ok i Will do my best it's at 1/4 throttle to 1/2 it will sputter smess
and then comes on strong. I started with a 165mj an a 42pj and it fowled the plug real good very black. but it starts good and idlis good. When i strarted to go down in size with the jetts it started to get better. That why i'm at 148 and 40pj. Also i have K/N and outerwares and Holes in the airbox. I hope this helps.

:)

(p.s. spell checker would be a help to)

[Ketch]

One last thing it's a new plug a Splitfire please don't chew me out.
If this cam does not work i have a stage 1 waiting in a box.

Thanks Jimmy:D

[skemp]

The 40 pilot should be good. The 148 main is WAY too lean. You would need more like a 165. I think the problem is in the needle. I don't see you mentioning doing anything with that. At the very least, drop the clip on the needle one notch. This would explain the flat spot in midrange. A flat feeling is usually lean. I am surprised it even runs past 1/2 throttle with the 148. And for the time being, forget about the plug, they are helpful in jetting, but in our world of oxygenated fuel with all the detergents they have, they aren't always accurate.
In summary, leave the 40 pilot, raise the needle by dropping the clip one notch, and put in a 165 main. I bet it wakes up then, but keep us posted.

Yea yea what he said. Skemp seems to have you covered.

It looks like the problem was in the pilot being too rich (42) but then when you changed that (40)you also went a little low on the main(148) hmmmmm.

First thing do just one change at a time so you get an accurate idea of the change. Its just too confusing if you make more than one adjustment.

The only thing thats puzzling me is the fact that your problem is at 1/4 to1/2 throttle. This range will start to get onto the main but is mostly controlled by the needle and pilot. And you stated that its ok after the mid into the top. Did it give you any trouble with the 165/42 set up?

What I am thinking is try dropping the needle setting as skemp advised and then after you test that try moving up on the main jet.

Just remember that the stage2 will give up a little bottom end power, but it shouldnt be a lot of loss.

[Ketch]

Thanks 440ex4me, Skemp, ccole400ex, I will be working on this problem this week end i have to the self employed thing all week long. I will keep you posted. 440ex4me i did sign the Petition to
last week. I thougt out here in sunny california is were all the nazi-anti any thing peaple lifed.:rolleyes:

Ketch those guys are everywhere.

I had worked with some of those tree hugger types in the past to help stop the crazy overdevelopment here in NJ and I know how they work or think and were gonna have a battle all across the country.

Good luck with the jetting, I know it has driven me nuts bfore

[Ketch]

Well i have it running real good now. I moved the clip on the needle to the last grove and the pilot is #40 an main is 165 for now. And for the hot cams it's very good value for the money.
It realy wakes up the powerband in the mid to upper RPM range and i didnt lose any low end. Thanks to every one with the help.
:cool: Jimmy