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Post by bignico2411 on Apr 15, 2016 15:15:01 GMT
Going to do the air filter mod, and know I need to upjet. But how far on the side of caution should I err before plug chopping etc? I've seen conflicting advice saying up 2 sizes (e.g 98 to 100) and others saying 10% (think the sticky on here says that) which, in my case would be almost 10 higher than my current 98 MJ. I know all scooters are different and it's not an exact science, but can anyone suggest a ballpark figure? And where should I be on the 'biscuit' colour scale for plug chops? I keep seeing 'tan chocolate' as the ideal plug colour, but this confuses me, as tan and chocolate are two very different colours to me  As for the mod itself, I'm pretty sure someone mentioned on here about packing the filter with cotton wool to catch the swarf, does that sound like a plan? Final question, specifically for Sime and/or H; one of you, as detailed on Sime's build thread, found an ebay seller doing non-OEM MJs for £2 a pop. Did he turn out to be legit and were his jets true to size? Thanks in advance Nick |
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Post by bryno on Apr 15, 2016 18:59:16 GMT
Which air filter mod do you mean?
10% increase is massive
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Post by henri on Apr 16, 2016 9:01:24 GMT
for a totally free-er filter an expansion pipe change up from stock ,10% increase is the ballpark safe figure to jump to then work down . for just drilling a stock filter up 2 numbers/1jet size ,from a 98 to 100 is were most end up.for safety coz every engines different i'd go 102 1st an see were that takes you . an greasing the cotton wool a bit an drill bit too to catch swarf ,an always blasting it with a air line to be sure of removing swarf .
cant remember the name off hand , but the jets you refer too seem to be off good quality,£2.50 an posted quickly .i'm using him for all my push in jetting now .H
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Post by bignico2411 on Apr 16, 2016 11:51:08 GMT
for a totally free-er filter an expansion pipe change up from stock ,10% increase is the ballpark safe figure to jump to then work down . for just drilling a stock filter up 2 numbers/1jet size ,from a 98 to 100 is were most end up.for safety coz every engines different i'd go 102 1st an see were that takes you . an greasing the cotton wool a bit an drill bit too to catch swarf ,an always blasting it with a air line to be sure of removing swarf . cant remember the name off hand , but the jets you refer too seem to be off good quality,£2.50 an posted quickly .i'm using him for all my push in jetting now .H I'm just doing the standard 7 and 5mm drilling, H, so I'll get a 100 and a 102 and see how we go. Good tip re greasing wool and bit, thank you. I saved that seller's name on ebay, just wanted to check he was on the level. |
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Post by bignico2411 on Apr 20, 2016 8:49:45 GMT
Apologies if this is a stupid question but, once I've done the mod and upjetted, should I be using a new plug each time or the one that's in situ to check lean/rich/ok?
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Post by henri on Apr 20, 2016 9:58:04 GMT
some use a new plug every time , i just use a new one to start with,to rule out a old plug giving problems . a used plug can need longer runs/chops so its got time to re-colour ,an ya need to take a photo to compare if ya memorys as crap as mine .a new plug can take longer to colour up 1st time out ,than a old plug re-colouring ,but will give a truer reading/less confusing one.no chance of mis-reading a old colour coz ya aint run it far enuff to give a proper take on the job . for a "proper" chop you need a new plug every time ,as the old ones been chopped ,literally cut in half .for are stuff a new plug to start with an then notes on colour changes as ya go is fine .long winded answer i know ,but cant get brain in gear today .H
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Post by bignico2411 on Apr 20, 2016 10:43:41 GMT
some use a new plug every time , i just use a new one to start with,to rule out a old plug giving problems . a used plug can need longer runs/chops so its got time to re-colour ,an ya need to take a photo to compare if ya memorys as crap as mine .a new plug can take longer to colour up 1st time out ,than a old plug re-colouring ,but will give a truer reading/less confusing one.no chance of mis-reading a old colour coz ya aint run it far enuff to give a proper take on the job . for a "proper" chop you need a new plug every time ,as the old ones been chopped ,literally cut in half .for are stuff a new plug to start with an then notes on colour changes as ya go is fine .long winded answer i know ,but cant get brain in gear today .H Cheers, H, as I don't plan on doing 'full' chops, I'll pick up a couple of new ones (spare for the glove box). Just so I'm clear, I fit the new plug once the mod and upjetting is done and then start the chop process? My understanding is that I should ride around for a bit to warm up the engine, then 30 secs at WOT, engage clutch and turn off engine, cruise to a halt then check plug (without burning fingers!). Black/sooty - too rich, downjet, grey/white - too lean, upjet, tan chocolate - happy days. Does that all sound about right? N |
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Post by henri on Apr 20, 2016 12:07:38 GMT
yep , but its more like 1 1/2 minutes for a full run . if working totally in the dark/new set-up i'll count sixty n check .so long as its not obviously lean i'll then count 90 an chop . an scoots got to be fully warmed up 1st ,usually the 2-3 mins riding to get to my "test-track" ,chosen chop road is how i do it .
an tan chocalates a confusing description really , simes biscuit scales a easier metaphor ,with 1 tweak ,your looking for a "ginger-nut" colour ,if memory serves we were using digestives as a gauge before .rich tea or lighter =danger/lean .bourbon an darker=safer but rich . its 14 degrees outside today over hear so lovely chopping weather . 10 degrees an lower an jettings going to be leaned up ,set right in those conditions an it will be rich over summer but perfect nxt winter . H
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Post by sime66 on Apr 20, 2016 12:49:19 GMT
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Post by bignico2411 on Apr 20, 2016 15:07:12 GMT
Thanks, gents! I remember the biscuit scale from Sime's rebuild thread, but couldn't recall the optimum biscuit. I'm quite partial to a ginger nut, too! I plan on doing the mod over the bank holiday weekend, so I'll report back once the job is done. Cheers! N
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Post by bignico2411 on May 9, 2016 8:14:50 GMT
Ok, so I did the filter mod over the weekend, upjetted to a 102 MJ, and stuck in a new plug. Couple of WOT runs (90 secs max), but plug hasn't coloured. Do I keep riding her as normal and keep an eye on the plug, or persist with the WOT runs? Feels like there's a lot more 'throttle' in 3rd gear before I need to change up, which I'm presuming will be the mod kicking in
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Post by vespasco on May 9, 2016 10:03:35 GMT
ride as normal
dont go WOT when you are swapping jets of different sizes
play it safe
try a 104 and come down if needed
the plug will need some more miles on it before it will colour
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Post by bignico2411 on May 9, 2016 10:31:50 GMT
ride as normal dont go WOT when you are swapping jets of different sizes play it safe try a 104 and come down if needed the plug will need some more miles on it before it will colour Thanks, mate, that's what I'll do. Do you think the 102 may be a little lean (I was on a 98 before mod)? I've saw people mention on here about a scoot being obviously lean; pardon my ignorance, but how would I know? |
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Post by henri on May 9, 2016 11:08:06 GMT
as vespaco says , go bigger on main ,he reckons 104 ,i'd prob jump to a 106 an look for a very black plug ,then come down 1 step at a time .an lean will give you a hot engine an very white even blistered looking plug . H
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Post by bignico2411 on May 9, 2016 12:54:45 GMT
as vespaco says , go bigger on main ,he reckons 104 ,i'd prob jump to a 106 an look for a very black plug ,then come down 1 step at a time .an lean will give you a hot engine an very white even blistered looking plug . H Cheers, H, I'll grab a couple of bigger jets off that ebay guy and see how we go. Any idea, miles-wise, how long a new plug will take to colour? I do about 10 miles a day commute |
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