decade weber idf knockoffs

[Scottinaz]

I was searching ebay and found some Decade brand knockoff IDF's for a reasonable price. supposed to be an IDF 40 clone, but takes IDF 44 parts Need to know if the published specs are close to what is needed for the Goldwing conversion prior to purchase. A simple yes/no will suffice, so there is no disclosure of "classified" information

here are the published specs for the venturiis and all


DECADE 40 Specifications: (Intended for dual application)
.52 Idle Jets, .115 Main Jets, .200 Air correctors, F-11 Emulsion Tubes, .200 Needle & seat,
.550 Pump Exhaust Valve Jet w/ Delrin balls, .50 Accelerator Pump Jets & 28mm Venturis.

Rebuildable with Weber 44 IDF rebuild kit.

· Quality castings

· Interchangeable with Weber 44 IDF components and jets.

· Enlarged Float Bowl, 20% more fuel volume.

· Cold Start Circuit eliminated.

· Profiled Throttle (Butterfly) Shafts

· Phillip head top screws.

· Float Bowl Vent filter screen.

· Extra long Venturi—Stack bolts to accommodate linkage plates and Billet air filter bases.

· Hex Idle jet holders.

· Dual linkage arms installed.

· Delrin Pump Exhaust Valve balls.

· Extended life accelerator pump diaphragm.


does this seem to be a decent deal, or am I barking up the wrong tree?? don't want to sink good money into crappy carbs, and still be where I am right now, only poorer...

[gregforesi]

I hadn't heard of that one and it looks like a new design. The expensive parts are correct but the jetting is off.
The "throttle enrichment circuit" that they eliminated was useless and you wouldn't want it anyway. Float bowls held plenty of fuel in the original Weber design but I can see where Decade saved money be eliminating some machining and a cover.

The EMPI 40 HPMX is also compatible. The first couple of years had porosity problems with the castings but newer ones are improved.

As for which of the three options is "best"...you gotta roll the dice. You can order Webers with Randakks recommended jetting and save a few dollars but your engine will be at least a bit different and you'll probably end up with a range of jets and air correctors.

[Scottinaz]

I had been looking at most of the options out there, Weber, Dellorto and Empi, and these seem the most economical for a starting point. Jets I assume can be gotten as part of a tuning kit? I also like the fact that they are brand new, but am scared that they are a bit of an unknown. For the price, I may have to be a guinea pig, and try them out.

After doing some searching, It looks like most of the jets are the same as the IDF 40/70 series, except the idle jet, which is a bit bigger (.52 vs .50). close enough to get into the ballpark I assume, and then tune from there?

[Scottinaz]

Well, I bought them. Paid $250 for the pair new shipped. Didn't want the hassle of trying to rebuild/recalibrate a used set, at more money. Now need to get the manifolds and build the linkage. Should be a fun journey.

[past in time tony]

Good luck with the new carbs. I just set my 1975 up with webers with the randakk set up. Still messing with jetting but was very ridable with the randakk setup tips. Cant wait to here how it goes for you, it would be nice to see a less expensive alternative.

[Scottinaz]

the carbs arrived yesterday afternoon, and look good. assembly quality may be a bit suspect, as I had to realign the butterflies on one carb, and tighten the throttle lever locknut on the other, but the parts do appear to be of decent quality. I cant really complain for new carbs (with 10 yr warranty) for $125 each, as the rebuild kit for the stockers is more than that. Being as these carbs are meant to be very tunable, I cannot complain about the minor assembly issues. Interesting thing is they are assembled with JIS spec screws (with the dot). would lead me to believe that these may be of Japanese origin. Once the remainder of my parts show up, I can begin assembly

[gregforesi]

Take the carb tops off and pull all the jets and idle mixture screws out. Place a piece of printer paper on your workbench. Hold the carb upside down and tap it on the workbench. If ANY crud drops out (left over bits from the machining operations) give the carbs a good cleaning before putting them in service. The bonus is that you'll start getting to know them.

I know you have a ways to go but I thought I'd throw this in. This is the basic "get it running" info and idle adjustment. (Mid-range and top end tuning are the advanced lesson.)

There are several books and a boatload of information on the web on how to tune 40 IDF's. This procedure is a composite of stuff I came across. Near as I can tell, this is how to do it right.

Starting point for tuning (with Randakk's suggested jetting):
1. If you have a vacuum leak you will never get it tuned.
2. Back the idle speed adjustment screws all the way out and then bring them in until they just touch the idle lever. Then bring them in an additional 1/4 turn.
3. The idle mixture screws should be right around 1 turn out from seated when adjusted to best lean idle so start at 1 1/2 turns out.
4. The air bleed screws (next to the idle mixture screws) should all be closed.
5. The cross-bike linkage between the carbs should start out connected.

Fire it up.
It will run like a cement mixer but it will run. Don't touch the idle speed adjustment screws. Opening them further causes the butterflies to start to uncover the progression holes and that is cheating versus how the carbs are supposed to work. Goose it with the throttle to keep it running. It should settle in a bit as it warms up. If it doesn't want to run then try going up a size on the idle jets before making an adjustment to the idle speed screws.

Adjust each idle mixture screw to best-lean idle. Go around and do them all again. If they need to be out 2 turns to run - then go up a size on the idle jets and adjust them all again. Same scenario if the mixture screws are only out 1/2 turn. In that case put in smaller idle jets. Be aware that the mixture adjustment may change as the engine gets to operating temperature. Again, the mixture screws should be right near 1 turn out when you get done doing the best-lean idle adjustment. If they aren't you will need to re-jet.

Sync:
With the engine running and warmed up - use the sync fan gizmo and check the throat of cylinder #1 against cylinder #3. If they aren't the same - you open the air bleed screw on the throat that is breathing less. Bring it up to match the other throat. Double check and then do the other carb.
Next sync left-to-right (cyl 3 to cyl 4). Depending on your linkage design you may have to disconnect the cross-bike linkage.
At this point you will have to touch up one or both of the idle adjustment speed screws.
Finally, adjust your cables (or cross-bike linkage) so both carbs lift off the idle stop screws at exactly the same time. Primary chains don't rattle when the sync is correct.

Webers run much better with velocity stacks even when using regular air filters and housings. There are short v-stacks available that fit inside the air cleaner. The air flow is significantly improved when the air comes around a radius instead of a sharp corner. The best performing velocity stacks have a full radius (as opposed to stacks like I'm running that just have a bell mouth). Velocity stacks are worth 2 or 3 horsepower.

[Scottinaz]

Carbs are on, and the engine is running. Need to do the final tuning, and probably rejet (I have the factory jets in there now), but I am happy so far with the result. 1.25 turns out on the idle screws has me with a good 1000 rpm idle with the butterflies properly adjusted. Have a bit of a return to idle issue, but this is due to the lack of an installed return spring (need to fab the brackets for this tomorrow. I then need to fine tune the linkage system, and take it for a ride. Ill have to watch what pants I wear, as being a bit taller than the average, my knee will choke out the rear carbs if I don't wear something close fitting.

[Scottinaz]

ok carbs are on, and fine tuned. all I can say is WOW, what a difference. The noise made once you hit 5000 rpm is like nothing else, just purely intoxicating, making you want to hold a lower gear to enjoy that song more. The good is that these carbs appear to work just fine, and are significantly cheaper than used Webers, and a bit cheaper even than the EMPI clones. Randakks manifolds are great, and the tuning hints help, but these carbs like to be tuned a bit different than the Webers evidently. I had to do some independent thinking and research to get the carbs to return to idle. The bad is that noise is so intoxicatingly beautiful that it will likely get me in trouble, due to a heavy right wrist. Control is needed to maintain legal speeds, as the throttle response is just out of this world. you can easily go from 40-90 in a matter of a couple of seconds, without much thought or wrist action. As for my cable linkage, it works, but is not ideal. I will retain one of the throttle wheels for the cable coupler, but will follow Randakks and Greg Foresi's lead in the cross carb linkage. Much easier to tune out the minor differences in carbs with their system.

[delling3]

Love to see some pics of your install . . .

[wingrider]

Out of curiosity, what is not ideal with your set up? It looked as if it might be a good alternative to the other styles of linkage.

[Scottinaz]

The system works, its just a bit sloppier than I would like. the style of ends on the cables does not lend itself to a fine adjustment, so getting the openings good is a pain, and keeping it there is a nightmare. the bike is rideable, and runs great, but I would feel better with a less sloppy linkage between the sides.

Here are a few pics to satiate the appetites of the curious











Just for the record, I have rain hats and air cleaners on the way. As it stands, small animals, children and other assorted items can very easily be sucked into the intakes.

[Scottinaz]

ok, I got the linkage items in yesterday, and installed last night/this morning. Had to modify my setup a bit, but this is how she looks now. Throttle feels much better than the dual cables. When I modified the CB350 cable, I left too much slack in the system, causing a lot of slop, and resulting issues. I could have decided to re-shorten the cable and remove the slack, but in the end this setup is better I think.

I still used one of the cable wheels, albeit modified to the linkage.





With this setup, I was able to remove one of the return springs on the carbs, and get a bit better of a feel on the throttles. Still need to cut the rod in the middle and add a fine adjustment, but that will have to wait until my LH tap and die arrive. without the center link, its a hard connection between the carbs, without a real fine adjustment. as it stands, its still better than the dual cable, but even that system could have been refined a LOT over where it was. Funny thing was, that system was still very rideable, and a big improvement over what I had before. Costwise, it is a bit cheaper for the setup I have now, vice the cable.

to finish the conversion, I still need to finalize the fuel lines (probably go with -6AN fittings, as I have a bunch of them from another project (and they look cool), relocate the fuel filter to a less conspicuous location (probably on the center support), remove and paint the manifolds, and build some rain hats. I don't like the products that are out there, so will try and build a set myself. we shall see how that goes. Keep in mind I live in AZ, so rainy season means no riding for me, mostly due to flash flood threats (I live up in the foothills, so most of the major roads experience some flooding). I would have taken this around the block a few more times this morning, but it started sprinkling again, and not only do I not want to be wet, I didn't want to flood out the carbies......

[past in time tony]

Looks good, this looks like a nice tight set up! Cant wait for your report.

[miltoncaniff]

The included velocity stack are a nice touch, but I see some sort of a low profile forward facing ram induction. That would also solve the loose pant issue.

John