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Old 02-22-2014, 11:19 AM   #1
Rob Farmer OP
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Dellortos what jets are you running?

Hopefully somebody with dells can get me in the ballpark for the jetting as a starting point.

As a tempory measure I've just slotted a tuned engine into my old pd. fitted with dells. Standard exhaust system. I know I'm not going to get the most out of it with that setup but it's just temporary.

1000cc

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Old 02-22-2014, 04:52 PM   #2
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As a starting point I started with stock R90S jetting. My '92 R100 with everything pretty much stock (8.5:1 CR) excepting a BMW sport cam and Staintune Sport mufflers ran good enough jetted thusly. I then went from those 155 mains down to 130's for a lot more power. I then shortened my accelerator pump throw a little at a time until I shortened it as far as it would go and it just kept revving quicker and pulling harder. I then removed my pump bell cranks all together and, except for a flat spot, it ran a lot stronger yet. I first got rid of the off idle flat spot minus the pumps going up from 260 needle jets to 264's. It ran real good like that but I think it runs a tad better yet minus the pumps with 1mm richer slides, K9 jet needles versus K4's, and 262 needle jets.

Since dual plugging, remapping the ignition, raising CR to 10.0:1, and major port work including going from 42 to 44mm intakes, it ran real well with the same jetting until I removed the airbox and shortened my stock velocity stacks about 5 inches for a lot more power from idle on up. While making the airbox changes, it started falling flat on it's face not too far up off idle like I was hitting the kill switch. Increasing the mains alone from 130's to 160's fixed that.

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Old 02-22-2014, 10:02 PM   #3
Rob Farmer OP
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Thanks SS. Good advice. Much appreciated.

I'll let you know how I get on.
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Old 02-23-2014, 07:54 AM   #4
chasbmw
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Rob, my 1070 bike runs 155 mains with standard exhaust and 165s with the Jim Cray straight throughs. Needle, slide and pumps standard.

1982 heads Dual plugged, ported, rubber mounted Dells.
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Old 02-23-2014, 08:21 AM   #5
Rob Farmer OP
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Thanks Charles. If your on 155 I may need to go down to 145 with the original gs exhaust fitted.

What choke cables did you use? I'm assuming there are lower cables available to suit?

I've just spent a couple of hours modifying my original gs throttle cables to make them fit. Cutting the outer back 15mm was easy enough but filing the original bing carb end down to a 3mm tube was a pain in the arse. Just need to turn a couple of stainless adapter for the top of the carb.

I'll speak to venhill next week to see about having some custom cables made.

I'm pleased with the way it's all come together considering they were originally 800cc heads. It all looks like it's supposed to be there.


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Old 02-23-2014, 09:39 AM   #6
chasbmw
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Thanks Charles. If your on 155 I may need to go down to 145 with the original gs exhaust fitted.

What choke cables did you use? I'm assuming there are lower cables available to suit?

I've just spent a couple of hours modifying my original gs throttle cables to make them fit. Cutting the outer back 15mm was easy enough but filing the original bing carb end down to a 3mm tube was a pain in the arse. Just need to turn a couple of stainless adapter for the top of the carb.

I'll speak to venhill next week to see about having some custom cables made.

I'm pleased with the way it's all come together considering they were originally 800cc heads. It all looks like it's supposed to be there.

Venhills made my lower throttle and choke cables, but I don't know the length of the inner cables. In the end I fitted individual choke levers to each choke. I'm not sure why. In terms of jetting I would start off high and then see what happens when you reduce the size....a Dyno might help!
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Old 02-23-2014, 12:58 PM   #7
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Originally Posted by Rob Farmer View Post
Thanks Charles. If your on 155 I may need to go down to 145 with the original gs exhaust fitted.

What choke cables did you use? I'm assuming there are lower cables available to suit?

I've just spent a couple of hours modifying my original gs throttle cables to make them fit. Cutting the outer back 15mm was easy enough but filing the original bing carb end down to a 3mm tube was a pain in the arse. Just need to turn a couple of stainless adapter for the top of the carb.

I'll speak to venhill next week to see about having some custom cables made.

I'm pleased with the way it's all come together considering they were originally 800cc heads. It all looks like it's supposed to be there.

The whole point is to go down in mains until it doesn't run and then go back to the next bigger jet. That's where the most power is. Jetting 101. Your butt or a dyno will get you to the same jets although I admit that I went back up two sizes (125's to 135's) just to be safe until I dynoed my bike and it still sniffed a bit rich so I went back down to 130's. Just that one 'size' change got me over one hp! You'll find that exhaust does not effect mains that much. It mostly effects just off idle jetting. The airbox setup effects mains a great deal more than exhaust.
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Old 02-23-2014, 01:06 PM   #8
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Originally Posted by chasbmw View Post
Rob, my 1070 bike runs 155 mains with standard exhaust and 165s with the Jim Cray straight throughs. Needle, slide and pumps standard.

1982 heads Dual plugged, ported, rubber mounted Dells.
I am guessing by 'standard' you mean R90S specs? My bike ran great like that. It just ran a lot better yet not jetted like that.
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Old 02-23-2014, 03:43 PM   #9
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I ended up with almost identical jetting to SS
Slides are a litle leaner
980, 9.5:1, 77 S heads, 308 cam, dual plug

Sticking with 155-165 mains prevented me from finding a better solution.
I would suggest K9 262 135 no pumps is the starting point
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Old 02-25-2014, 11:55 AM   #10
Rob Farmer OP
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Just been out for the first run. Fantastic would be an understatement, obviously it's a fully rebuilt engine so I'm taking my time but it pulls very hard up to 4k and then really wants to go. Going to have to wait a while for that pleasure.

I put it together with the standard 90s jetting and standard plastic airbox just to see where it's at. The only issue I've noticed is between 2 and 3k under load (riding up a hill) it's pinking slightly. this stops completely at exactly 3k. There's also a tendency for it to hang onto the revs slightly as it comes back through the 3 -> 2k transition when it's in neutral.
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Old 02-26-2014, 06:28 AM   #11
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I can relate to that having had much the same experience on the R90S setup
One large snorkel and one small seemed to make a positive difference.
Two large made it worse
Now I'm back to two small after a couple of trips around the jetting block to get to where I am now.

I find the 2-3000rpm range really useful especially if I want to hold third on slower sections (37/11)
My riding style is sort of oposite to the demands SS asks of his engine yet we ended up with very similar jetting solutions.

Very interested to hear what you end up with.

P.S. congratulations on the first run - hope you have heaps of fun
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Old 02-26-2014, 08:46 AM   #12
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Memories of Ducatti ownership have just come flooding back (literally)

Lovely day here so I thought I'd have a run on the bike. Turned the fuel on and within seconds there's a pool of fuel all over the floor. Turns out the floats on the right carb are both full of petrol, looks like the seams are leaking. Pain in the arse! I'll have to wait until I can get some more delivered.
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Old 02-26-2014, 09:37 AM   #13
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Quote:
Originally Posted by Rob Farmer View Post
Memories of Ducatti ownership have just come flooding back (literally)

Lovely day here so I thought I'd have a run on the bike. Turned the fuel on and within seconds there's a pool of fuel all over the floor. Turns out the floats on the right carb are both full of petrol, looks like the seams are leaking. Pain in the arse! I'll have to wait until I can get some more delivered.
That sucks, they look like new carbs? Pretty shoddy if they are

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Old 02-26-2014, 11:26 AM   #14
Rob Farmer OP
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Pita for sure. Brand new carbs.

The seams on both floats on one carb weren't welded or glued on the back edge. Once the fuel was out I just took my soldering gun to them and melted the seams together. It may not last but at least I managed a decent run out and a little more fettling.
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Old 02-26-2014, 02:11 PM   #15
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That's the second quality issue on here with dels recently, doesn't say much for
them!

Hope you're getting new floats for free
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