needle and jet sizes?

chris-stockton · Post by **chris-stockton** » Sat Jul 20, 2013 10:15 pm

ok guys, so i stripped my eddy 500 down today. And heres the info ive got so far.

needle = 6347
primary (i think - the ones near the middle of the carb) = 383
secondary (the ones at the back of the carb) = 375 i think.

the info on the secondary jets was a nightmare - im confident on the 3 and 7 but not the 5, was near impossible to see.

pump spring - had no colour markings on it at all?

any comments on the above spec?

cheers

chris

sidecar · Post by **sidecar** » Sat Jul 20, 2013 10:51 pm

The jets go up in 3 thou sizes, the smallest being 77, the next would be an 80, then 83, 86, 89.....

The 'middle' jets are the primaries. Your setup is 8% leaner than base on cruise and virtually as stock on the acceleration circuit. You maybe able to go leaner on cruise. A 65-47 rod used with a 83 jet will lean off the cruise to 16% leaner than base. Your springs maybe the silver ones which have no colour, having said that the colour falls off the other springs anyway!

Johnny Rotton · Post by **Johnny Rotton** » Sun Jul 21, 2013 4:32 pm

Likely the secondary jets are 95 thou. I have tried 83 primaries and 63-47 rods, but once I fitted the Innovate AFR gauge, it was clear that this could be leaner. Next set up tried was 86 primaries and 68-52 rods, which is 12.5% leaner on cruise. Went well, but wanted to see if it could go leaner still, so tried 83 primaries and 65-52 rods. On cruise car was hesitant, but on acceleration, it hooked up really well. So too lean on cruise at 16% leaner than stock setting, but acceleration felt good.

So have gone back to previous set up, but have asked Muscle Manta to send me some 68-57 rods to try with 86 primaries. Will report once I have tried this.

Although your car appears to have similar spec to mine, there may be differences, so you really need to sort out an AFR gauge. Got mine from Graham Goode Racing and had a bung welded on to the exhaust pipe before the silencer.

chris-stockton · Post by **chris-stockton** » Mon Jul 22, 2013 7:43 pm

hello,

cheers for the info guys, was looking online to try and find one of those tools for measureing the jet size - im looking to just match the original spec from the old carb for a bit till i can get an AFR gauge on it.

The last dubioius RR session I had, the guy told me it was a bit to lean on cruise and when coming on throttle, but WOT was pretty good.

I know I need some proper data - but just looking to get it back on the road asap when my new carb arrives

sidecar · Post by **sidecar** » Mon Jul 22, 2013 8:13 pm

chris-stockton wrote:hello,

cheers for the info guys, was looking online to try and find one of those tools for measureing the jet size - im looking to just match the original spec from the old carb for a bit till i can get an AFR gauge on it.

The last dubioius RR session I had, the guy told me it was a bit to lean on cruise and when coming on throttle, but WOT was pretty good.

I know I need some proper data - but just looking to get it back on the road asap when my new carb arrives

Hi Chris,

I take it from your post that your have bought a new carb, if it is an Eddy 500 then the jets and rods will transfer from one carb to the other without a problem. If I was buying a new Eddy carb I'd go for the Thunder series. The jets and rods are still transferable, the Thunder carb has a spring loaded adjuster for the air valve which covers the secondaries.

As to the rolling road bods comments I think that you should run the cruise as lean as possible up to the point where any leaner causes a bad throttle response. If your throttle response was OK on cruise then it was not too lean.

If you are going to sell your old carb I might consider buying it!!!

Cheers,

Pete

chris-stockton · Post by **chris-stockton** » Mon Jul 22, 2013 9:01 pm

hello, ill PM you re old carb

my throttle response isnt great to be honest, a few times ive experienced a hicup when putting my foot down so i suspect something wasnt great,

chris

sidecar · Post by **sidecar** » Mon Jul 22, 2013 9:41 pm

chris-stockton wrote:hello, ill PM you re old carb

my throttle response isnt great to be honest, a few times ive experienced a hicup when putting my foot down so i suspect something wasnt great,

chris

Maybe is it s bit lean on cruise then. It could be that the accelerator pump needs a tweak although personally I think that in some ways they can just mask a small problem. Also they can cause a rich bog too if they dump too much fuel into the manifold. An LC1 will show this sort of problem.

Johnny Rotton · Post by **Johnny Rotton** » Tue Jul 23, 2013 9:18 pm

I would be surprised if 83 primaries and 63-47 rods set up is too lean, as this is only 8% leaner than stock on cruise. What air filter set up do you have and which hole is being used on the pump shot lever ? As Sidecar says, it could be a rich bog that causes the hesitation. You could try using the outer hole on the pump shot lever.

sidecar · Post by **sidecar** » Wed Jul 24, 2013 4:37 am

8% may seem not to be two lean but you never know. Muscle Manta and I built a stage II 3.9 lump for a chap, it would only run right on cruise when it was 0% leaner than the base setup, the acceleration circuit was 11% leaner. This is why I don't really like to give out carb settings these days....there are too many variables which have an effect on the carb.