SuzukiSavage.com - boosting the thumper

Matthewfriez YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 1	Re: boosting the thumper Reply #75 - 03/03/14 at 16:22:34 Its too bad there isn't a bolt on EFI conversion... That would make adding a TC/SC a bit of a breeze. I hear the newer model is EFI. Someone should get brave an hack a brand new one down!
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savagebob Full Member Offline SuzukiSavage.com Rocks! Posts: 235	Re: boosting the thumper Reply #76 - 03/03/14 at 16:40:15 yes and no, EFI makes it easy if you have a programmable computer. If not, and the injectors are only adequate for a stock application it can make things more difficult. Once I get to the bottom of the behaviour here my setup should be pretty straight forward I hope.
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savagebob

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Re: boosting the thumper
Reply #77 - 03/04/14 at 02:34:40

Alright I think I got to the bottom of it. I checked all the clamps.. no change.. I tightened up manifold bolts.. no change.. I rejected carb.. no change. I took off VM36 and slapped the stock CV carb on.. and the problem disappeared.

I don't think a round slide is going to be a good carb for this project.. the vacuum caused by the SC just pulls air and fuel through it seems.

A real shame.. I had that carb all setup. So.. anyone suggest an alternative? Searches bring up the mikuni HSR 42 as being the best draw-through carb but could be too big..

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ChrisTech Junior Member Offline SuzukiSavage.com Rocks! Posts: 58	Re: boosting the thumper Reply #78 - 03/04/14 at 05:23:13 Bob, Any way you can post a YouTube video of it running, can't view your Facebook video on this stupid ipad. I'm dying to see it running, glad to see it's working out.
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Dave YaBB Moderator ModSquad Offline SuzukiSavage.com Rocks! Posts: 18104 Camp Springs, Kentucky Gender:	Re: boosting the thumper Reply #79 - 03/04/14 at 05:24:52 Savagebob: You might try ditching the UFO before you abandon the Mikuni.
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savagebob

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Re: boosting the thumper
Reply #80 - 03/04/14 at 13:06:12

Yeah I'll give that a go - if the UFO is removable.

I actually think the CV carb might actually be better. I can use a way smaller carb as the SC creates the vacuum and will draw the air and fuel it wants. I'd have to rejet much larger of course..

Chris - I'll do a youtube video later on, at this stage running at idle isn't really that exciting. I'd rather get a GoPro vid of me savage boosting down the street

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Steve H Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1223 Spartanburg, SC Gender:	Re: boosting the thumper Reply #81 - 03/04/14 at 16:20:26 You can get an EFI kit. check out http://www.ecotrons.com/products/
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savagebob Full Member Offline SuzukiSavage.com Rocks! Posts: 235	Re: boosting the thumper Reply #82 - 03/04/14 at 18:10:31 Interesting, but I'd rather keep it old-school. Also I doubt the electrical system is up to running a high-pressure fuel pump and EFi. Righto, I removed the UFO and put the mikuni back on - no change. It just doesn't like the slide carb. How much fuel can the CV carb flow with jetting? Enough to fuel 60hp?
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markbacon

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Re: boosting the thumper
Reply #83 - 03/06/14 at 15:05:25

Don't know if this helps, but anyway ...

In a normally aspirated engine at idle there's a lot of pressure pulsing in the inlet tract that alternately pushes air out and sucks it in. So the bottom edge of the butterfly or slide, where the idle orifice is located, sees both in and out air movements for each intake stroke. Each movement sucks fuel, so idle circuits are actually tuned lean because they're going to deliver a double dose.

The SC will be damping out the pressure pulsing, so idle circuit would have to be re-tuned to suit. Since idle circuit is usually a branch off the pilot circuit, the pilot jet may have become a limiting factor in the VM36.

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savagebob Full Member Offline SuzukiSavage.com Rocks! Posts: 235	Re: boosting the thumper Reply #84 - 03/06/14 at 17:15:26 Limited as in the fuel delivery or limited in the design? I changed pilots a few times with the VM36 and couldn't get a changing result. I'm going to rejet the original CV and run with that I think. MarkBacon..you're not from Christchurch are you?
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markbacon

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Re: boosting the thumper
Reply #85 - 03/06/14 at 22:24:59

Limited as in fuel delivery. The CV carb will probably be easier to tune - slides look easier but there's all sorts of things you can end up having to stuff around with to get them right - slide cutaway, accelerator pump adjustment, needles, etc. CV might not give you the same potential but it takes care of a lot of things for you. You'd be very unlucky to have to do more than idle screw, pilot/main jets, needle position.

One thing to watch with the standard CV is the enrichment circuit - that's the diaphragm operated one on the side. If that's crusty it can make things unhappy - pull it apart and clean it out, especially the tiny drilling in the diaphragm cover. The spring in there seems to be the culprit in the famous savage banging on over-run. It's too stiff and closes the enrichment circuit before revs have dropped far enough for the idle circuit to deliver enough fuel. Running slightly over-rich pilot jet and idle screw can mask this. If you want to sort this out properly, someone on this forum found a softer spring from an outboard. Somebody else tried cutting the spring, but I think that ddin't work out too well.

Not Chch - Wellington

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savagebob

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Re: boosting the thumper
Reply #86 - 03/27/14 at 02:17:59

Ok time for an update. It's all running and I took for my first ride today. I've had a funny time with the CV carb. Ended up putting some VM36 pilots in which were too rich at idle until I dropped down to a 12.5. Shaved white spacer to half size. 170 main.

I've also put one range colder plug in.

It's a bit harder to start than normal and requires a bit longer on the enricher before it will idle ok without it. Much louder and deeper noise, have had to put a baffle up the back of the drag-pipe to quiet down some.

Took it around for a spin. Currently running more boost than I was expecting. Looks like it will run over 10psi which is a bit much. Runs way to lean so I'm going to take white spacer out completely, put a 15 pilot and a 200main and see what happens.

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Yoshi Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 874 LongIsland, N.Y. Gender:	Re: boosting the thumper Reply #87 - 03/27/14 at 03:50:54 I think you left out the most important detail, is it any faster?
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curmudgeon YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 23	Re: boosting the thumper Reply #88 - 03/27/14 at 05:10:09 Got any video? I'm dying to hear what it sounds like!
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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: boosting the thumper Reply #89 - 03/27/14 at 09:49:52 If that thing is makin 10 PSI boost AND the mix gets lined out,, then its Gonna be faster,, Keep swinging at it, man!
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