My 77 Cafe idf build

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dontwantapickle
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Joined: Fri Oct 13, 2017 9:26 pm
Location: Colorado

Re: My 77 Cafe idf build

#16

Post by dontwantapickle »

gregforesi wrote: Mon Jul 12, 2021 6:53 pm The OEM's are fine. They just don't run as well.
run as well as what?
Giving bad advice is worse than just saying "I don't know."
Olyclo
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Joined: Tue Nov 07, 2017 6:10 pm

Re: My 77 Cafe idf build

#17

Post by Olyclo »

gregforesi wrote: Sun Jul 11, 2021 10:06 am "It is however nearly unrideable as it pops and backfires until about 5000rpm and then it clears and pulls hard ( if I use full throttle )"

There is no mid-range circuit so the idle circuit must be rich enough to transition to the mains. The accelerator pump is a big part of that transition too. I have a pretty easy flowing system with the velocity stacks and (now) Delkevic exhaust. My settings are: 50 idle jets, 110 mains, 135 air correctors, 9mm of thread showing on the accel pump adjusters.
Your low speed mixture screws should be between 3/4 and 1 turn off the seats. You will get that with either a 47 or 50 idle jet.
The bike should idle with the butterflys open by just 1/4 turn on the idle adjusters. Any more than that and the progression holes start to get uncovered and can give you a false impression.
If the bike is falling on it's nose at 3000 - 3500 or something like that it's the accelerator pump. Crank it down to show more thread (less squirt).
My #1 problem was with Randakk's suggestion for the air correctors. You can see that I ended up a lot smaller than his. That was the result of a dyno run. The accelerator pump adjustment was trial and error.

So when I first started out I was getting way too much squirt from Accel pumps and it bogged. Then as it got to the top end it was getting way too much air through the air correctors and it was running really lean. Instead of buying a bunch of air corrector jets I invested in micro drills. The brass solders closed nicely and then I just drilled them to size.
Sent you a PM Greg, Thanks
77 Gl1000
Olyclo
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Re: My 77 Cafe idf build

#18

Post by Olyclo »

Greg I fitted 55 idle jets today ( the only size I had ) up from 47. The difference is incredible! Still far from perfect but rideable at least. Il order 52’s and try them out.
77 Gl1000
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lilleG
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Re: My 77 Cafe idf build

#19

Post by lilleG »

Great looking bike! Well done!
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gregforesi
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Location: Venice, FL

Re: My 77 Cafe idf build

#20

Post by gregforesi »

dontwantapickle, I had the bike on a dyno with the Webers and it made ~73hp. Stock was 61 so I'm thinking it runs better with the Webers. There may have been some effect of the 3.7 GEM rear gears I put in, but I thought the nearly 20% gain in horsepower was a pretty good kick by just changing carbs.
I seem to recall that the stock GL1000 was 61hp, with the Webers we'll call it 71hp, fuel injection gets near 80hp and with a blower they are about 90hp. No matter what you do they always make 60-65ftlbs of torque. There are no cams available and you can't really change pistons or the stroke so I suppose that's a reason the torque numbers stay pretty static.
I'll mention this as an aside - the dual 40 IDF Webers total about 425cfm while a 34 PICT is about 115cfm. Has anyone here ever come across single carb conversion dyno numbers?

On a sad note, I have been forced to go back to the drag bars. The clubman riding position just got to be too much for this old man. Oddly enough it wasn't my back but rather my wrists and thumbs that got sore as all my upper weight was on them.
2006 GL1800 (Brutus Maximus)
1978 GL1000 (White Trash - 2012 BOTY
(If you want to discuss the Trashmobile, Webers, Rearsets, Clubmans, or other stuff then send me a PM.)
"Getting old ain't for sissies" - Phyllis Diller
"So how much you gonna spend to win that $5 trophy?" - Cyborg
robjordan406
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Joined: Tue Aug 31, 2021 10:39 pm

Re: My 77 Cafe idf build

#21

Post by robjordan406 »

Greg, I love that carb setup B-17 look.... It fills up that outer space nicely...... Nice job on your build....
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