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Post by 90GTVert on Sept 27, 2010 9:42:28 GMT -5
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Post by aido21 on Sept 27, 2010 16:33:45 GMT -5
thanx, that guide looks helpful, I didn't get a throttle cable with the dellorto kit, does this matter, will the current one for the 12mm carb work?
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Post by 90GTVert on Sept 27, 2010 17:03:02 GMT -5
Never used a smaller Dell carb. Try it and see unless somone here knows for sure. Sometimes the connections are fine, but the stock cable is too short. That's the case with the 24/25mm Dells I have, but hopefully not a problem on smaller ones.
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Post by aido21 on Sept 29, 2010 12:04:19 GMT -5
Took off the old 12mm carb, noticed the 17.5mm has a few more brass spouts on the inlet manifold side, the black line running from across the head of the cylinder over the plastic air flow cover (not sure what it does), not sure which one to fit it to?
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Post by 90GTVert on Sept 29, 2010 12:25:22 GMT -5
You can trace the hose to be sure, but the line from the oil pump runs as you described. That would be my guess. It's the hose around the shroud in this pic. The carb should have a fuel inlet that is usually the largest nipple on the carb. It may have an oil injection port. The others are probably for fuel overflow from the bowl. If you have a couple of pics of the new carb it might help someone give you positive IDs for the ports.
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Post by aido21 on Sept 29, 2010 14:38:58 GMT -5
yeah I will post a few pics of the old & new carb tomorrow, I think the throttle cable(for the original carb) is too short the needle isn't resting fully down into the carb, I've tryd lengthening as much as it will go but no joy, was looking online for a longer one but they all just say throttle cable, no length, what size carb to be used with etc. would you know where I could look for one??
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Post by aido21 on Sept 30, 2010 10:22:15 GMT -5
Here are some pics You can see the the two large ports on the left, I think it should go onto the narrow one on the right, just not sure tho The 2nd pic, you can see the needle slide, thats as far down as it go's, its not near the idle screw, is this enought? this why was thinking maybe need a longer cable
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Post by 2strokd on Sept 30, 2010 12:39:44 GMT -5
I think your right, it looks like the oil line should go there. Might wanna put a little oil in the carb mouth by hand just to make sure it gets oil in the first start up. The other two could be for vac, or vents maybe? Not sure.
You will need to get that slide down all the way at idle or it will be reving and want to take off when you start it. Looks like a cable is in order for that one.
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Post by aido21 on Sept 30, 2010 12:55:29 GMT -5
thanks man, I managed to get the slide down all the way, by cuttung one of the alum necks down to size, the join to the cable isnt great so only temporary, where would I get a longer throttle cable for that carb? Im struggling to find one on the net, how many turns out should I have the idle screw when starting her up for the 1st time?
Cheers
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Post by 2strokd on Oct 1, 2010 7:57:30 GMT -5
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Post by aido21 on Oct 5, 2010 14:21:54 GMT -5
So I got the carb on n jetted ok (i think) it has a 90 main n 34 pilot, seems to be running alrite, but its fairly sluggish, spluttering over the line, not at all responsive,need to give it almost half throttle to take off, could this be that I havnt jet'd her correctly, or maybe just transmission needs a bit of messing around after goin up a bigger carb?? im not sure what the problem is
Cheers
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Post by 90GTVert on Oct 5, 2010 16:11:49 GMT -5
I would continute tuning the carb first. Tune the idle mixture screw. Adjust it to get the highest idle speed and then go 1/8 turn or so more rich just to be safe. Then adjust the idle speed screw so it idles at a safe RPM that doesn't stall and doesn't spin the tire. You can also tell if it's close by just barely opening the throttle. It should respond quickly to the small movement if it's right. Also, adjust your throttle cable so there isn't much play to get it to feel the best.
If that doesn't show you any real improvement you might need to start over. Tune the main jet first. Make test passes with a clean plug at WOT. Shut the engine off (ign or kill switch) at WOT and coast in. That will show you what is going on at WOT. Change main jet sizes accordingly.
The next step is supposed to be tuning the mid throttle postions with the needle and clip, but I move to the idle settings again. Do just what I told you above. If you can't get the idle correct, you may need to swap pilot jets.
Once the idle is dialed in, then I move on to tuning for good part throttle performance with needle and clip positions. I don't do plug chops here usually, just tune by feel. Moving the clip up (needle down) will lean the mixture from roughly 1/4-3/4 throttle. Moving the clip down (needle up) will richen the mixture in those positions. Sometimes you'll need to go back and touch up the idle settings after a needle/clip change.
When tuning, you need to use the feel and sound of the engine to give you an idea of what you need. You can hear rich and lean conditions and you should pay attention to the amount of smoke or lack of smoke to give you general ideas. Don't tune by smoke amounts, but if you see a ton of smoke it's probably too rich and if you are seeing no smoke at any point it's probably lean or you're not getting oil. If it's rich it might chug and pop and sounds kinda "thick" if it's lean it usually makes kinda of a BWAAA or hollow sound.
If you can't get anywhere with all that, check for intake leaks or anything out of the ordinary and then move on to the trans. The fact taht throttle position is dictating whether it's sluggish or not points to the carb to me though.
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Post by aido21 on Oct 5, 2010 16:22:01 GMT -5
Cool, thanx a lot for the advice, i'll giv it a go, the idle mix screw is one thing i dont know very much about, can I move it without worrying the bike will take off?? clockwise is rich (like the idle speed screw) yeah?
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Post by 90GTVert on Oct 5, 2010 20:35:59 GMT -5
Clockwise should richen on that one. If the idle gets high enough that the tire is spinning when you are trying to adjust the mixture, just use the idle speed screw to back it down.
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Post by aido21 on Oct 6, 2010 9:24:18 GMT -5
ok, i'll give it a go later this evening see how I get on, I think I have the idle mix screw 1 & half turns out currently.
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