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Zippers G3 carb

Started by tmwmoose, September 21, 2018, 05:31:12 PM

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tmwmoose

I decide to try one out on my 117 twin cam it comes bored and all the bells and whistles . I have a a/f gauge so to see what's going on . First business is the intermediate jet which in my case is super lean they supplied a .035" to start with. Ok I go up a thou and still very lean all in the 2 thru 3k rpm range so on and on I go a thou at a time and it does slowly improve.Well I sent the carb back for them to inspect after I drilled out a .041". I'm almost there but I don't know what's going on here never had one of these modified Super Gs and there's no dialogue coming back to me from good ole Zipper's either! So anyone here have experience with THIS carb of there's ? Is the bored out throat got the air speed so slow this is to be expected?  Thanks

turboprop

You will probably here the same story as mine. Couldn't make it work in the midrange/cruize area. Tried real hard. One T-Jet, 2x T-Jet, just couldn't flatten out the cruise area. At WOT they perform fantastic.

On my 124 Smack-A-Hoe I tried a standard out of the box G. As expected it was either too rich at the top or two lean down low.

The standard Zippers G3 (bored venturi, 1x Thunderjet, external air bleed, re-timed emulsion tube, re-timed idle circuits) fixed the idle issue and sort of straightened out the upper mid range and lower top end (if that makes sense). But it was still dangerously lean in in cruise area.

The G3 w/2x Thunderjets was better. We tried a bunch of different sized air bleeds for the T-jets and got them timed as good as we could. Spent a few days on the dyno doing this. The result of this is posted in the dyno section here. The break in tune made 153 Hp SAE with a table top flat torque line, but was still dangerously lean in areas.

In the end I wound up putting a Mik48 on and lost a few HP (Above 6k, dont dive a darn). But the low and midrange areas are so much better.

This bike has an AFR display permanently installed on the riser clamp. Makes for a fun time. Rarely do I ride the bike without making some change to the carb afterwards. The just in the Mik are very close to perfect. The weather screws them up. What is perfect today is not tomorrow.

I have the G3 with dual T-Jets on the shelf if you want to try it. For your intermediate jet, there are a couple different schools of thought on this. There is the Zippers way, ie big fat int jet. Others will say to bring the intermediate jet size down along with the main jet size and air bleed and let the T-Jet do the heavy lifting. I tried. Spent many days on a dyno and drill press. Best of luck to you.

Added - This is the tune that worked best in the G3 w/Single T-Jet,  .036 int., .084 main, 147.5 T-Jet, 190 air bleed.
'We' like this' - Said by the one man operation.

speedzter

Nothing to add, but I would be pretty annoyed after spending that sort of money on a Carb' and it's not right.
I love how tunable the Mik 48 is, and could never see myself trying an S&S.

tmwmoose

September 22, 2018, 11:00:09 PM #3 Last Edit: September 22, 2018, 11:05:26 PM by tmwmoose
Quote from: speedzter on September 22, 2018, 07:47:50 PM
Nothing to add, but I would be pretty annoyed after spending that sort of money on a Carb' and it's not right.
I love how tunable the Mik 48 is, and could never see myself trying an S&S.



I have a fine running 48 Mik that's been on it just wanted to try a change . Got the carb back from ZIPPERS all they did was LOOK at the transition ports , didn't make any changes and said to "try this and see how it works". Anyhow no change I'll see Monday how well there return policy is but this maybe on me since I asked for it. I'll put on the shelf next to Ed's.
Note, other that the lean area the carb does haul ass, shame.

turboprop

Update.

I put the G3 carb on my black/gold FXR with the EVO 124" when I sold the bike to a local a few months ago. I tried talking him out of the carb but he really wanted it. The new owner mounted an AFR gauge on the bike and set about tuning. Got it pretty close to perfect, well except for that lean spot at cruise in RPM. He has since worn Zippers out. They are currently redoing the transition between int and main. Not sure what that entails but am anxious to see how that cruise area is after the carb comes back from Zippers. Outside of the very narrow lean area, the bike runs fantastic with the G3. If for some reason the lean spot is still there when the carb comes back the next step is to take the entire bike to Zippers. They really want to work this this out and my black/gold FXR with an evo 124" is the perfect test platform. More to follow.
'We' like this' - Said by the one man operation.

Ohio HD


wfolarry

I'm interested to see how this turns out.
When I had trouble tuning that carb I put the DaVinci kit in there. Back when S&S first came out with their 95" kit they had the Super G carb in the kit. Too much carb for the motor. Put the DaVinci kit in a lot of them then. I don't know if they're still available. I have a Super G on my 88" Evo with the DaVinci kit. Runs great. I'm rebuilding a Super E now & will see how that works. Have an AFR gauge going on there too so I can see how well it does [or doesn't].

turboprop

Update:

We decided to have a small science project while the G3 carb is still at Zippers. I loaned the owner one of my Mikuni HSR 48 carbs and the various accouterments required to mount and filter it. Just to see. Owner is giddy with the results of the Mik48. He went to the next size richer pin (clip in center position) and will probably increase the main from the oem 190 to maybe a 195 or 200. The AFR (measured with a 4.9 Wide Band) while cruising around 3k rpm in any gear results in an AFR of 13.5. The engine leans out a little at WOT with the rpm above 4k, but that is an easy fix. Regardless of any combination of any combination of jets or bleeds, the G3 was never able to get below 15:1 during this same condition. The owner also reports that the bike is more responsive, the engine does not feel as hot when it is shut down, his chest appears larger and chicks think he is cooler. We both really want to see what Zippers comes back with in regards to their G3. I hope they don't try to blame the lean condition on reversion. More to follow.
'We' like this' - Said by the one man operation.

turboprop

Quote from: wfolarry on March 30, 2020, 03:13:07 AM
I'm interested to see how this turns out.
When I had trouble tuning that carb I put the DaVinci kit in there. Back when S&S first came out with their 95" kit they had the Super G carb in the kit. Too much carb for the motor. Put the DaVinci kit in a lot of them then. I don't know if they're still available. I have a Super G on my 88" Evo with the DaVinci kit. Runs great. I'm rebuilding a Super E now & will see how that works. Have an AFR gauge going on there too so I can see how well it does [or doesn't].

Zippers has returned the G3 carb. I plan to put it back on my red bike along with the Guppy and see how it does now in the trouble areas it had before. Will probably not happen until after the FXR Jam.
'We' like this' - Said by the one man operation.

RTMike

I had a customers bike here had a Zippers 107 billet big bore kit on it  120 hp but same issues  at cruzing rpm.I tryed every trick in the book same thing,replaced it with a Mik 45. Customer was extatic .