Scoot seems flat ????? Any help would be good

[shovel1]

Hoping you guys can help me, I had a heat seize a few months ago, I took my scoot (Vespa PX 125) to a chap local whom stripped engine to find autolube had seized and stopped working so he’s disconnected it, fitted new seals through out changed carb to dellorta non autolube and had the barrel (150cc rebored to next size) but he’s put the original jet stack in??? at the moment I’m running in with approx 100miles done but all seems very flat I’ve tried a couple of jets approx 104,108 but should I look higher any help would be greatful, and thank you in advance
Ps I’ve been putting in 3% oil is this correct I just wanted to make sure the seize doesn’t happen again as it shook me up a little as I was doing 60mph at the time😬😬

[mijapxman]

Shovel1, need a bit more info; what age is your scoot, what exhaust.

You should be using a 2% mix, your actually making it run a little leaner using 3% as it's getting less fuel.😉


mij☺

[ironsloth]

Think a 104 would be right, but as mij says, what exhaust are you using? Have you been ragging the sh*t out of it whilst running in? Or have you been treating it with kid gloves?

[shovel1]

Nononnono no raging it’s something i noticed as from time to time to blip the throttle but no real response (exhaust is sip double barrel) I’ll empty the tank and put 2% in but I really was thinking on the caution side of things any further help I would be grateful as I’ll be taking her a run after work, the plug is ngk8 and on chops the top looks sooty but the probe is brown, when I tried the lower number main jets there seemed to be a couple of pops as Revs dropped like a blowback???

[shovel1]

Forgot to say it’s 2003 vespa px125 (possible Heinz addition) and thank you both for all your help/knowledge 🙌🏼

[mijapxman]

I wouldn't go as far as emptying the tank, just put 2% in next time you fill up.

How old is the exhaust? Unfortunately I have no experience of those exhausts, but they may just jet the same as the single tailpipe ones, will have a search on the net later to see what comes up.

What's the other jets in the carb?

Have a look here 👇,Bud 

www.sip-scootershop.com/community/forums/p/418014/2366495.aspx

Mij☺

[shovel1]

Mijapxman you a top geezer You’ve provided info that not only proves I’m not going mad but also answers which I’ll work through and post a conclusion 🙏🏼I’ve gone With what you’ve suggested and added 2% to a new can of petrol and filled the tank with that I’ll keep topping up until I’ve got through it all and🤞🏼🤞🏼🤞🏼All will be good with the minor adjustments though I’ve a feeling the main jet will be 106-110 as like I said it tends to back fire a little when Rev dies off even low Revs or going down hill with no throttle I’ll keep everyone posted and thank you it’s s major break through with the info on the link you sent thank you 👌🏼

[ironsloth]

You need a starting point but I reckon 110 is too big. I'll check the sloth tomorrow and see what she runs (polini 180, Scorpion exhaust, dickhead rider).... I don't think it's any bigger than a 114 and it's kitted. Are you using the autolube again? I would change the plug to a NGK BP7ES as the spark from an 8 may just be too hefty for a 150 (I used to use a 7 when mine was "standard"), what plug cap do you use? NGK do a rubber right angled one, but I can't find a spare, my shed is a mess of parts (car, scoot and bike)... look at this link, you want a cap similar to the one in this kit:-

rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F223470480220

This one is a Champion one, but I do prefer the NGK one, purely because that's what I have used.

[shovel1]

Good evening ironsloth thanks for your input it’s greatlly appreciated yep regards the cap etc I have that exact one reason behind running the ngk8 was purely I’m lead to believe it’s cooler on longer journeys??? I ride when happy with scoot 40mile round trip on open Cornish meandering roads at stupid o’clock in the morning so I’m free as a bird but not thrashing it’s lovely ride to work/home though I know the major issue is dealt with by the local lad but in comparison to how it did ride it feels like a lull only on top end it used to pull from 3-4 throttle up but not at the moment I’ve got a little to work with and thanks once again, if possible when ur looking at your old lady what idle jet are you running as I believe that can have a impact even in 4th, thanks again fell and good evening👌🏼

[mijapxman]

Shovel1 , have a look at mista freak mopeds YouTube site , in his playlists you'll see a file on how to set up si carbs.

His other playlists are WELL worth a look. He's a member on here, but not on much, I usually pass him a message if needed.



Oh! And he's worth subscribing to 😉.


Mij☺

[shovel1]

Thanks for all the replies I’ve been busy and I’ve just got back to messing around with it again and still no joy the cheap cheap noise is driving me made my idle jet is a 55/160 is this an issue I need to start riding her again but I’m so unsure about things I’m even debating selling her on 🥺🥺 stack is 140/be3/105 gone up and down from 98-116 this seems best setting🤷‍♂️🤷‍♂️
Seriously need some advice I’ve utubed it to death with no further progression if someone can help uploading a video I’m willing to show what I’m dealing with😬😬😬😖😖😖😖😖😖😩😩😩😭😭😭

[phattanglo]

The popping and sluggish throttle response might suggest a leak somewhere.
If it helps I would suggest concentrating on your jetting in the lower rev range while you're running in your rebore with your main jet a bit rich and then plug chop for your final main jet setting.
If your lower range jetting is on the weak side and you compensate with your main jetting, you run the risk of your engine nipping up when coming down from a prolonged ride with wide open throttle.
I've read that many heat seizes are the result of this rather than at full throttle.

[shovel1]

Good morning that is my thoughts at the moment is the idle jet at the moment too small I think it was 55/160 or 55/140 but deffo 55 what ideal jets are people running? And how do the sizes work ? Thank you once again for your input🙌🏼👌🏼

[mijapxman]

I also think it may be an air leak, no point in trying jetting till you find if it is an air leak.

The popping sound may be coming from your cylinder head being loose, have a look and see if it has oil dripping down from it, or better still , check and retighten the cylinder head nuts to spec, if all fine, at least that's been eliminated. 😉

Also check the spark plug is in tight.

Also see the replies you got about this on the" not so modern forum", as they posted a link that may help you.😉

Mij☺

[shovel1]

After more analysis it would seem the chap whom did all the work for me has shafted an already helicoiled thread as it now attached to the engine stud and obviously won’t/can’t tighten to any torque this seems to be my issue and possible chirping fault due head not completed sealing😡😡😡🤯🤬🤬 I’m looking to put a high temp high strength thread lock on and as good as weld the bar steward in place I’m f’ing livid ggrrrrr (thoughts 🤔🤔🤔) thanks for all your input thus far as I found this issue by loosening the nuts and re-torquing via a suggestion from someone on here

[shovel1]

Also when I’ve done heads etc previously I’ve put spring washers and flat washer on matey has just put flat washer on ?? Is this professional practice or am I over doing things? Thoughts

[shovel1]

Also when I’ve done heads etc previously I’ve put spring washers and flat washer on matey has just put flat washer on ?? Is this professional practice or am I over doing things? Thoughts

[mijapxman]

Yes,use flat and spring washers, Bud.

You can buy oversized cylinder studs from Beedspeed which may work straight into the case, depending how big the hole that is left from the helicoil.

First over size stud 👇

beedspeed.com/products/vespa-cylinder-barrel-holding-stud-1st-o-s-primavera-px125


Second over size stud 👇

beedspeed.com/products/vespa-cylinder-barrel-holding-stud-2nd-o-s-primavera-px125

Mij☺

[shovel1]

Mij many thanks the link helped and I’ve ordered them I’m of the position now that any work that needs doing I’ll do it at least I can guarantee that there will be no short cuts or untold errors, your help is greatly received, cheers fella

[shovel1]

Just been out for 3rd run and all seems wonderful in the world 😎😎😎☀️☀️☀️☀️😁😁😁thanks for all your help it would seem chap over tightens or fcuk hellicoil all re down all locktite and torqued down sounds nice with a deep barbel noise hmmmmmm and the chirping/ backfire has gone when coming off throttle, torque is bk though only a couple of thraps to check very 😊 Wishing everyone a great sunny scooting weekend☀️☀️😁😁

[mijapxman]

shovel1,glad to hear all's well, have fun😀. Wish I could be out scooting in this weather, but my arthritis in most of my major joints has giving me to0 much pain for the last few days. Cheers me up, knowing I was of a small help.


Mij☺

[shovel1]

Mij so sorry to hear your health is restricting your enjoyment, hopefully the pain will subside to a degree that will let you enjoy two wheels again 🙏🏼🙏🏼, take care fella and thanks one again for your input