Advice on jetting

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wee nor
Posts: 7
Joined: Wed Jul 30, 2008 10:18 pm
Location: Scotland

Advice on jetting

Post by wee nor »

After fully rebuilding my storm and binning the high level pipes and cans, I have fitted SP Engineering carbon stubby cans. Ran it up on the stand and it runs really rough and throws flames when throttle is closed ! I removed and checked the carbs and found kit needles with 6 grooves, 48 pilots and 180 mains, the needles are set on the second richest groove and the air/fuel screws are set at two and a half turns out. the slides have three holes in each. Should I re-jet both the pilots and mains, should I blank off the holes in the slides ? Help please :( :(
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VTRDark
Posts: 20010
Joined: Sun Mar 18, 2012 9:24 pm

Re: Advice on jetting

Post by VTRDark »

That's a dynojet kit you have there by the sounds of it. If your spitting flames then it's a sign of running rich, I expect the running rough is bogging down from being too rich also. The flames will be the unburnt fuel spitting out. Also what air filter are you running? If you temporarily take the filter out and it runs a bit better this will confirm it running too rich.

The 3 holes in the slide is that including the one in the centre where the needle goes through or is that 3 lift holes. If that is 3 lift hole then I would block 1 hole in each slide with some epoxy resin. But do a neat job of it or that will upset things.

The best way is to take the needle holder out and put something behind the hole so epoxy does not fall through and make a mess behind and the glue also has something to rest against and dry flush on the rear. A second fill once dry and sand down the smooth on the front. These bikes don't run well with the extra lift hole that Dynojet install instructions say to do.

Have a read through the following on jetting and tuning carbs
http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=14214

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wee nor
Posts: 7
Joined: Wed Jul 30, 2008 10:18 pm
Location: Scotland

Re: Advice on jetting

Post by wee nor »

Thanks for your reply, sorry I meant to state it has a BMC filter fitted. I popped out to the garage, whipped out the filter, re-fitted the lid, started and warmed up, still spitting flames, but much, much better ! I will resin the holes in the slides, drop the needles and set mixture screws one and a half turns and try again. Once again, thanks for your help.
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VTRDark
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Joined: Sun Mar 18, 2012 9:24 pm

Re: Advice on jetting

Post by VTRDark »

1.5 turns on the fuel mixture screws may be too much from 2.5, especially as you going to drop a clip and lean the needles as well. With 48's between 2 and 2.5 would be about right. If you had 50 pilots then 1 to 1.5 turns would be about right. Get the slides and needle height sorted first. :thumbup:

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lloydie
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Joined: Mon Jan 17, 2011 11:16 pm
Location: In the garage somewhere in Coventry

Re: Advice on jetting

Post by lloydie »

Mine has 48s and the mixture is at 1.5 1.75 out
This is like other carb settings every bike is different so best to start at 2.5 and turn them in 1/4 of a turn at a time till it's smooth and you get around 100 miles a till the light .
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