Dual carbs gl1100

[Daijen]

I'd also be curious to know if anyone has run this type setup with straight pipes. My very limited knowledge tells me I'd have to run a richer mix, but with the easily accessed dual carbs it would seem like the ability to adjust as needed would be there. Or that's my weak theory and I'm sticking to it--until I learn better. Great thread.

[gregforesi]

I ran straight pipes for a bit. Not as brutally loud as the megaphones without baffles, but loud.
The combination of open exhaust and free intake means more top end HP but will cause it to run lean at high rpm. You might need to go to 115 mains, but first try going smaller on the air correctors. I'm running 145's over the 110 mains with essentially no air filters and race baffles that I opened up even more. I had to give it more squirt on the accellerator pump as well.
I've said this before..."When I get it down around 27mpg, I know I've been having big fun!" Nobody makes this mod for fuel economy.

[Daijen]

I ran straight pipes for a bit. Not as brutally loud as the megaphones without baffles, but loud.
The combination of open exhaust and free intake means more top end HP but will cause it to run lean at high rpm. You might need to go to 115 mains, but first try going smaller on the air correctors. I'm running 145's over the 110 mains with essentially no air filters and race baffles that I opened up even more. I had to give it more squirt on the accellerator pump as well.
I've said this before..."When I get it down around 27mpg, I know I've been having big fun!" Nobody makes this mod for fuel economy.

Excellent. Exactly what I wanted to know. Thanks.

[Millwright]

Here is a couple pics of the mufflers I installed. Made by Super trapp. The thing I liked about these mufflers, is that they are adjustable in that, the more plates you add to the end of the muffler, the more air flow you get out and the louder they get. The ones I bought came with 15 plates, so that is what I started with. I liked the sound, not too loud but louder than most stock wings. A nice rumble. As far as jetting goes, keep in mind that Gregs bike is a 1000 cc. Looking at his numbers you should bump them all for the 1100cc motor with these mufflers. I run air fuel mixture guages all the time and when the main jets kick in about 4000 rpm, I am about 12.5 on the gauges. They provide more than enough power, for the riding I do.




Millwright

[Blackmagic]

The key to doing this entire thing is buying the manifolds from Randakk. That gets you the manifolds AND 45 pages of instructions. Priceless in making the conversion.

[Daijen]

Here is a couple pics of the mufflers I installed. Made by Super trapp. The thing I liked about these mufflers, is that they are adjustable in that, the more plates you add to the end of the muffler, the more air flow you get out and the louder they get. The ones I bought came with 15 plates, so that is what I started with. I liked the sound, not too loud but louder than most stock wings. A nice rumble. As far as jetting goes, keep in mind that Gregs bike is a 1000 cc. Looking at his numbers you should bump them all for the 1100cc motor with these mufflers. I run air fuel mixture guages all the time and when the main jets kick in about 4000 rpm, I am about 12.5 on the gauges. They provide more than enough power, for the riding I do.

I don't know if they're for me, but they look awesome on your bike. I had a custom 100" Evo at one time, used the Supertrapps and liked them quite a lot. The info helps a bunch. Thanks




Millwright

[Daijen]

The key to doing this entire thing is buying the manifolds from Randakk. That gets you the manifolds AND 45 pages of instructions. Priceless in making the conversion.

That thought had definitely occurred to me. I will definitely do that. Thanks

[earthquake]

I would think 36mm Dellorto's would be perfect but they have not made dells since the early 90's and parts are getting harder to get, If you can find a set CB Performance should be able to get kits for them.
Avoid Webers made in the USA they have a porosity problem and have internal leaks, Italian Webers are considered the best but Spanish made IDF's are pretty good too. EMPI carbs are ok if you get the later model carbs, the early one had a few problems.

Casey

[gregforesi]

This isn't specific to this build, and maybe it should go somewhere else, but here it is. It's something that anyone running V-stacks has to deal with. Here's what I did.

Without a covering air filter housing, there are holes in the carb tops that need to be dealt with.
Here are a couple of photos of the mods I made to the carb tops to keep junk out.

This first shot is of the topside of the carb top. The yellow circles show the idle air inlets. In the green circle is the block I made to keep junk out of the fuel bowl vent. The orange ellipse is of the vent holes that go into the cold start circuit. You really don't want a carb with the cold start circuit. The holes are there anyway and simply get plugged with JB weld.
The velocity stacks are actually built for the 44IDF (I couldn't find ones specific to the 40) and so are a bit large though they do bolt right up. With the V-stacks mounted, I scribed a circle around the ID of the bottom of the V-stacks and then used a die grinder to open up the big holes in the carb tops so the incoming air wouldn't have to flow over a step. Bottom of the hole stayed the same size so in essence just the angle of the taper changed.

IMG_1300.JPG

Here is a view of the underside of the top. You can see the straight "blind" hole that goes into the aluminum block. The block itself is 3/8x1" aluminum with the bottom shaped to fit into the fuel bowl vent hole. JB weld keeps it there.
Within the red circles are the pieces of air filter foam (from an old weed wacker motor) that I cut to fit into the carb top. They work quite well and need to be cleaned once a year. The filters should be put in place before you put the gasket and float / needle back in.

IMG_1304.JPG

Finally, here is a shot of the cross hole that goes up into the aluminum block and intersects the vertical blind hole. The fuel bowl can vent, but debris has an extremely tough time trying to jump up into that hole.

IMG_1302.JPG

[Daijen]

I would think 36mm Dellorto's would be perfect but they have not made dells since the early 90's and parts are getting harder to get, If you can find a set CB Performance should be able to get kits for them.
Avoid Webers made in the USA they have a porosity problem and have internal leaks, Italian Webers are considered the best but Spanish made IDF's are pretty good too. EMPI carbs are ok if you get the later model carbs, the early one had a few problems.

Casey

Thanks Casey. There is a shop in Mansfield that is full of old bikes and bike parts. Might check with them on the DellOrtos. Thanks again.

[Daijen]

[quote="gregforesi"]This isn't specific to this build, and maybe it should go somewhere else, but here it is. It's something that anyone running V-stacks has to deal with. Here's what I did.

That is great stuff. Thanks so much for taking the time to post this. Really helpful. You guys might actually keep me from drowning when I dive into this.

[desertrefugee]

I'd also like to thank Greg for having posted so many tidbits when he went through his conversion. The trouble is, he posted so many tips in so many places, I'm still discovering bit of it. Like the comments above regarding exposed inlet holes in the carb top when running stacks.

Dang it...right after I buttoned mine up.