salo
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Posts: 27
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Jetting
Oct 3, 2016 19:14:51 GMT
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Post by salo on Oct 3, 2016 19:14:51 GMT
I've got a stock PX125, I've just put a SIP road 2 on and a 100 main jet. I'm very very new to scooters, (3 months). Just heard about drilling the air filter. My question is what size drill bits and how high should I go with the jet.
Salo
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Post by bignico2411 on Oct 3, 2016 21:22:38 GMT
Did this fairly recently, you'll need 5 and 7mm bits. Pack the filter with cotton wool to help catch the swarf, and put a dab of grease on the bits to do the same thing. Make sure you clean the filter out thoroughly afterwards, I gave mine a blast with an airline, you do not want swarf going into your engine. Jetting wise, I went up from a 98 to a 104 and worked down after checking plug colour to a 100. But every engine's different, so err on the rich side of caution and come down until you have a nice digestive colour on your plug
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salo
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Posts: 27
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Jetting
Oct 3, 2016 21:40:26 GMT
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Post by salo on Oct 3, 2016 21:40:26 GMT
Thanks, I'll give that a go on the weekend, waiting for jets to arrive, I've got a 100 jet in now so I think I'll put in a 104 and take it from there. Thanks againot for your advice.
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salo
2nd Class Ticket
Posts: 27
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Jetting
Oct 5, 2016 12:21:10 GMT
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Post by salo on Oct 5, 2016 12:21:10 GMT
Probably a silly question but would drilling hole 4/6 or 6/8 make much difference? Also I've since heard that you need to go up10% on main jet. Hope this all makes sense..
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Post by bignico2411 on Oct 6, 2016 8:07:56 GMT
Drilling the filter increases the airflow, which 'leans out' the mix, hence the need to upjet. If you went 6/8 as opposed to 5/7, then I'd be inclined to go up 10%. It'll probably be way too rich when you plug chop, but better to be safe than seized and sorry. Conversely, if you went 4/6, then a 5% jump would probably be more than enough. These are only guidelines, though, every engine is different
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salo
2nd Class Ticket
Posts: 27
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Jetting
Oct 6, 2016 9:18:52 GMT
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Post by salo on Oct 6, 2016 9:18:52 GMT
Thanks for advice. It's a minefield! Just want a bit of umph without having to mess about with the engine. Not really wanting too much top end just wanted more acceleration
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Post by bignico2411 on Oct 6, 2016 9:25:39 GMT
Take a look at the sticky at the top of this section, mate. This mod will not give you any increase in your top end speed, but you'll get there quicker, if that makes sense. A simple power increase, not a speed one
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salo
2nd Class Ticket
Posts: 27
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Jetting
Oct 6, 2016 13:47:33 GMT
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Post by salo on Oct 6, 2016 13:47:33 GMT
OK thanks, will.read through the posts later when I finish work. It does make sense what you said.
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salo
2nd Class Ticket
Posts: 27
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Jetting
Oct 7, 2016 12:25:20 GMT
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Post by salo on Oct 7, 2016 12:25:20 GMT
I have a sip road 2 with a 102 main jet, if I drill the filter what size jet do you think I should go.up.to?
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Post by bignico2411 on Oct 7, 2016 14:11:37 GMT
I have a sip road 2 with a 102 main jet, if I drill the filter what size jet do you think I should go.up.to? I'd be inclined to go up as far as a 108, maybe even a 110 to be on the safe side, and then work down after regularly checking your plug colour. What your looking for is a nice digestive biscuit colour on the plug; black and sooty is too rich, grey or white is too lean.
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Jetting
Oct 11, 2016 8:26:44 GMT
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salo likes this
Post by scooterbooter on Oct 11, 2016 8:26:44 GMT
Hello I'm on the same set up. I took out the whole heart shape and I'm on 108.
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salo
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Posts: 27
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Jetting
Oct 11, 2016 15:01:49 GMT
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Post by salo on Oct 11, 2016 15:01:49 GMT
How and when do I check the plug colour? Is it after reaching certain RPMS and is it through all gears?
Hope this makes sense. Also will I notice the change,in other words, is it worth doing.
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Post by bignico2411 on Oct 13, 2016 8:02:52 GMT
How and when do I check the plug colour? Is it after reaching certain RPMS and is it through all gears? Hope this makes sense. Also will I notice the change,in other words, is it worth doing. Take the scooter for a good run to get properly warmed up. If it bogs down (revs drop), particularly in fourth, then you'll know without checking the plug that your mj is too big. Once you get back home, take out the plug and look at the colour of the cone (bearing in mind that a new plug will take longer to colour than an old one). If the plug is black and sooty, you're too rich, so drop a mj size; if it's white/grey, you're too lean so go up a size. What you're looking for is a nice digestive biscuit colour. Is it worth doing? My own experience is yes, it is. Scooter is more torquey through the gears, has better pull up hills and is a bit sharper off the lights. As stated before, you won't get any more top end speed, your scoot will just be a little more responsive. It is a cheap and simple mod. P.S use a glove to take your plug out, those wee feckers get warm!!
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Post by pxguru on Oct 13, 2016 16:06:25 GMT
The main plug chop is done after a full throttle run at maximum running temperature. I usually do 5 miles wide open, then take the plug out at the side of the road. This gives the most accurate result for the main jet size.
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salo
2nd Class Ticket
Posts: 27
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Jetting
Oct 15, 2016 18:30:33 GMT
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Post by salo on Oct 15, 2016 18:30:33 GMT
Drilled the filter today. 6&5 coz that was the only size bits I had. Put a 108 jet in. Haven't had time to ride it yet, will do that tomorrow.
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salo
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Posts: 27
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Jetting
Oct 16, 2016 14:23:01 GMT
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Post by salo on Oct 16, 2016 14:23:01 GMT
Went for a ride today, accelerated through all the gears as often as I could. Checked the plug when I got home and it was a light sandy colour. Hoping that's the colour I'm looking for?
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Post by henri on Oct 16, 2016 16:29:46 GMT
cant find it but , "simes amazing biscuit scales " what ya want . basically to take guess work out of it as to what shade youve got we use biscuits as a internationally recognised grade . arrowroot/rich tea/custard cream =too light =lean =bad thing . bourbon/charcoal/dog biscuit = dark=rich not good but safe . you want a digestive colour ,dark sandy to chocolate (milk not plain) ,ok . so "light sandy" i read as rich tea ,so just a tad lean ,1 size up on main an try again . still trying to work out were jammy dodgers come , best guess biscuit=lean an red of jam=the blood of scraped/burnt knuckles . opinions please lads ,like me dodgers an dont want em left out the scale . H
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Post by sime66 on Oct 16, 2016 17:52:59 GMT
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salo
2nd Class Ticket
Posts: 27
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Jetting
Oct 16, 2016 19:06:51 GMT
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Post by salo on Oct 16, 2016 19:06:51 GMT
OK from memory I'm thinking it's a custard cream colour. Also I forgot all about the plug chop. I just found a quiet road and opened up but waited to get home before checking the plug.
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Post by RWS74 on Oct 22, 2016 19:35:06 GMT
Mine's all set for tomorrow am.... cross town traffic to A41 Herts and WOT for a good 5+ miles.. then road side check where safe. What a massive change so far on a short ride. Felt like I gave Signora Vespa a nebuliser and cured her asthma.
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Post by RWS74 on Oct 25, 2016 9:27:12 GMT
Well Sunday's ride went well, I fitted a new NGK BH7S plug then rode around 40 minutes urban traffic then 10 miles WOT on dual carriageway before plug chop. Engine pulls really smoothly and consistently from 1st to 4 when on 1/2 TO full throttle. I performed a plug chop and this is the result. Probably too early to tell correct colour as only done around 50 miles on new plug. I also set the fuel mix screw as best I could. It was a pain but managed it with 7mm spanner by firstly turning idle screw down to slow then turning idle screw each way until I heard it running faster then opening throttle and repeating. My only grumble was the low end riding at 1/4-1/2 throttle feels a little ropey & sounds to my mutton ears with hearing aids to be bubbly, does that mean too lean or too rich in the pilot circuit? Do I need to up the pilot again or even lower it? Once I open to half throttle it pulls and sounds lovely. I tried a 48 pilot jet yesterday which helped a bit but still sounds & pulls same < 1/2 throttle. The video is taken yesterday after installing 48 pilot & riding for afternoon & readjusting fuel mixture & I think I've set the idle too fast.. Current set up: Main 100 Pilot 48 Air Filter Drilled.
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Post by pxguru on Oct 25, 2016 12:05:37 GMT
I would say that's a comprehensive test and plug chop.
In my opinion that is running dangerously lean, the little silver pimples are bits of melted piston! This usually means at least 2 jet sizes under. I would fit a 105 main jet and try the plug chop again. The SI carbs start pulling on the main jet from just under 1/4 throttle, or even less if the throttle is lower but revs are high to increase the suction. Increasing the main jet could fix all of the issues at once.
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Post by RWS74 on Oct 25, 2016 12:39:59 GMT
I would say that's a comprehensive test and plug chop. In my opinion that is running dangerously lean, the little silver pimples are bits of melted piston! This usually means at least 2 jet sizes under. I would fit a 105 main jet and try the plug chop again. The SI carbs start pulling on the main jet from just under 1/4 throttle, or even less if the throttle is lower but revs are high to increase the suction. Increasing the main jet could fix all of the issues at once. Thanks PXguru.... will adjust & report back.
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Post by RWS74 on Oct 25, 2016 15:33:44 GMT
I managed to get a mate to pick up 3 main jets from a scooter shop in SE16 that is an Aladins cave while I'm at work today.
102 105 106
Will start with the 106 before my commute home tonight and see how that goes.
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Post by RWS74 on Oct 26, 2016 13:40:47 GMT
I put the 106 in and it did feel a little better, not quite a plug chop due to time constraints but this is the plug 10 miles urban riding with a cheeky 50 mph on short dual carriageway then I took it out when I got home.
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Post by bignico2411 on Oct 26, 2016 14:31:31 GMT
Looks too rich to me, try the 105
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Post by RWS74 on Oct 26, 2016 17:57:50 GMT
Looks too rich to me, try the 105 Ta, I think you're right, I'm gonna up Pilot jet tomorrow to see if I can smooth bottom end. Going for the SIP Zen of 2.8 55/160 tomorrow from ,https://g.co/kgs/f61B7r they are a Scooter Emporium in Sarf East London, I will fit it before my ride home and adjust fuel screw when warmed up.
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Post by pxguru on Oct 27, 2016 3:11:25 GMT
Plug looking better overall. I would agree the main jet is 1 over, 105 would be better. A photo showing the root of the electrode would confirm this. No need to worry but next time I would put in a B6HS plug too. Could go a tad hotter. All the black oily stuff round the rim comes from running rich during low rpm use. I would think a 55/160 will make this way worse. What atomiser and AC are in, BE3 and AC160?
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Post by henri on Oct 27, 2016 7:06:10 GMT
as above , cone looks good to me too , personally i'd leave the 106 in an lean the pilot jet by 1 . that will lean the mixture all through the range ,about the same as dropping the main by 1 in the end . H
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Post by RWS74 on Oct 27, 2016 10:53:44 GMT
Ta Folks, B6HS fitted & 105 before I read your post Henri. Will see what my ride home is like and go from there.
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