PaintItBlack Posted November 22, 2023 Posted November 22, 2023 Trying to understand why my Mk1 B12 runs so rich, only did a couple of hundred miles on my newly acquired bandit before I started to pull it apart to modify it, before I pulled it apart I rigged up my air/fuel gauge, just to see what it was saying, very rich , 10.5:1, from as soon as I touched the throttle up to over 100mph, then leaned off a bit 11.5:1 after that, still very rich, bike was running stock airbox with k&n filter, noisy end can was expecting to find worn needle jets, but they look good, main jet fitted is 100, stock is 102.5 needle clips were in second groove down,4th is stock can’t see any numbers on the needles, and they have some notches just below the grooves which don’t look stock, the notches vary slightly from one needle to another as though someone filed them in by hand, also six grooves , is that stock, thought stock only had five ? have a stage 3 dynojet kit on order, so will be swapping needles and jets soon, just trying to confirm I don’t have other carb problems that need addressing first Quote
Gixer1460 Posted November 22, 2023 Posted November 22, 2023 They don't look like std steel needles - i'm leaning more towards DJ needles? What do the MJ's look like as if you've got the needles, you'll likely use jets as well? Only seen one set of Blandit DJ needles and seem to remember them having little taper with blunt tip but could be wrong! Quote
TonyGee Posted November 22, 2023 Posted November 22, 2023 they don't look standard B12 ones to me either. Quote
PaintItBlack Posted November 22, 2023 Author Posted November 22, 2023 33 minutes ago, Gixer1460 said: They don't look like std steel needles - i'm leaning more towards DJ needles? What do the MJ's look like as if you've got the needles, you'll likely use jets as well? Only seen one set of Blandit DJ needles and seem to remember them having little taper with blunt tip but could be wrong! Just as I was reading your reply the postie turned up with my new dynojet kit , now I’ve compared the needles I can see the needles that I removed are dynojet needles, with additional notches that someone added for some reason, can also see the springs that came with the kit are the same as the ones already fitted , so would seem somewhere in this bikes murky past, someone fitted a dynojet kit , the guy I bought the bike from thought it was running rich, and said he’d given the carbs an ultrasonic bath, and they are very clean, but he didn’t say anything about a dynojet kit, so guess he didn’t fit it, seems I got some spares now then Quote
Jaydee Posted November 22, 2023 Posted November 22, 2023 1 hour ago, PaintItBlack said: the postie turned up with my new dynojet kit Get on to Dynojet UK and Vicky will swap your used needles for new ones. Lifetime guarantee on DJ needles. Save the new kit or sell it on. Quote
PaintItBlack Posted November 22, 2023 Author Posted November 22, 2023 5 minutes ago, Jaydee said: Get on to Dynojet UK and Vicky will swap your used needles for new ones. Lifetime guarantee on DJ needles. Save the new kit or sell it on. Worth a go I suppose, spent the afternoon fitting the new kit, but if I can swap the old needles for new Quote
Upshotknothole Posted November 22, 2023 Posted November 22, 2023 (edited) If it's running rich it's most likely the emulsion tubes are worn. You'll have to call them to order emulsion tubes, but they're a fraction of the price of a full kit. In the future, you can drop the needles a notch when it's running rich like that to verify if it's the tubes. It's only a band aid fix, but it'll help clear up the bogging in the mid range if that's the problem. Also, DJ needles are usually titanium. Edited November 22, 2023 by Upshotknothole Additional info Quote
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