plug colour should I care?

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Snails
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I'm trying to get my scooter set up right but I dont seem to be able to find a set up that works and gives me a brown coloured sparkplug throughout the throttle positions.

I'd always thought that this was necessary but I was speaking to someone the other day with a lot more experience than me and they were totally dismissive of the idea of looking at the plug colour at anything other than on close to full throttle

However if that's the case why do people talk about ideally setting scoots up on dyno's so you can spot any hidden areas where it might be running lean at throttle positions other than full?

Anyway so today I'm having a go at setting up one of my scoots again - its using an sh1/20 carb and I'm dropping down main jet sizes and taking it for a test drive down the road after each change

98 - really boggy so cant get to 20 meters
96 - boggy still cant get anywhere
94 - boggy
92 - feeling a little better but cant really pull 3rd at all
90 brilliant. Drives really nicely so took on a couple mile drive just on low to mid throttle (with occasional very short blip just to see how it goes) as I'm still running it in but when I had a look at the plug back at home its very white

Now I will obviously try a 91 just to see how that runs (once I get one) but I've been through this a couple of times with different atomisers and there does not seem to be a middle ground, but then again should I care?

(its a Lui 125 3 speed running a sh1/20)`
mick1
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On full throttle mine ran perfectly, (100 mile plus)......but I popped my piston doing 60 mph (about half throttle). Turns out I had an air leak and had over compensated at full throttle (main jet), but not with my needle/slide/atomiser at half throttle.

Good luck if you don't plug chop at 1/8. 1/4. 1/2 and full throttle
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garry inglis
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ive just had my ts230 dynod and i had a major lean spot at 1/8 throttle right in the spot when you roll off from high speed if not found would have blown engine for sure
Strummer10
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Set mine up myself on the Avanti and then had it dyno'd by specialists and it was mildly tweaked on the jetting but always has a black slightly oily plug (always has done) but runs perfect all of the time....so yes not sure the chocolate plug will ever be achieved for me lol
Scooterdude
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Snails wrote:I'm trying to get my scooter set up right but then again should I care?

`
Well you know yourself how much it's cost you up to now and you must have a good idea of what it will cost you if it goes pop, so yes you should care!
A good starting point is the cam lam help pages.
Snails
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OK, so if I should care, and like some have said I don't want to pay to replace parts then what should I do in my example where it is the main jet that is affecting the performance but it's either too boggy to drive or lean?
alanscottj
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Snails wrote:OK, so if I should care, and like some have said I don't want to pay to replace parts then what should I do in my example where it is the main jet that is affecting the performance but it's either too boggy to drive or lean?
Put it on a dyno :)
Lambretta Series 2 Rat - RB260, SuperTourer, Cyclone 5 gearbox 😎👍
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DigDug
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Snails wrote:OK, so if I should care, and like some have said I don't want to pay to replace parts then what should I do in my example where it is the main jet that is affecting the performance but it's either too boggy to drive or lean?
The price of a dyno session and a couple of jets will be far cheaper than rebuilding your top end. :idea:
Did you have to do that?
alanscottj
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DigDug wrote:
Snails wrote:OK, so if I should care, and like some have said I don't want to pay to replace parts then what should I do in my example where it is the main jet that is affecting the performance but it's either too boggy to drive or lean?
The price of a dyno session and a couple of jets will be far cheaper than rebuilding your top end. :idea:
Whilst trying to get my jetting right on my TS1 I have probably spent the equivalent on a dyno run in petrol with all of the running around I've been doing :lol:
Lambretta Series 2 Rat - RB260, SuperTourer, Cyclone 5 gearbox 😎👍
Scooterdude
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Judging by the relatively small jets you are using and the fact it bogs on a 98 and 96 it sounds like an air filter issue as I was happily running a 128 main jet on a similar set up but it would start to bog on a 130.

The same situation I found my self in with my current set up until Darrell Taylor suggested I take the filter off then try a bigger jet.... it worked a treat, so try it with a 125-128 main jet and no filter just as a test and see how it goes. I was also using a 5998-1.5 atomiser as well if that helps + 45 or 50 pilot jet.
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