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Hey peeps, not sure how much appetite there is for performance parts reviews, but I'm an endless tweaker and can indulge my scooter tuning fantasies. This data may be useful to people looking to do similar upgrades? I'd have saved a fair bit if such reviews were more readily available.

I originally had a smallframe as a teenager, and got bit by the tuning bug after swapping an exhaust and noticing how different the revs and power curve was. That led to more exhausts, eventually expansion chambers, and a DR 133cc cylinder kit. My 1979 smallie had 6V electrics, unregulated and continuously blowing bulbs, points ignition which was absolutely all the rage in the 1950s etc.

This August I bought a 2005 Vespa PX150 with disc brake and electric start, not to mention fancy bourgeois accoutrements like 12V, regulated(!) electrics (all the latest 1970s technology!) and a battery that powers... the DC horn and starter motor.

It's my second largeframe, and I bought it for the latest/last classic Vespa tech. Things like CDI, better electrics, front Disc Brake that would cost a fortune to add after the fact and is outside my comfort zone installing. It's basically a platform, and I'm on a journey to create the perfect Vespa.

So going from underperforming stock, to well tuned, and how each performance part or mod feels and adds to the overall character, was kinda what I was thinking.
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PM Tuning UK's PM24ev
First thing I change on a Vespa is the exhaust, as it's so fundamental to 2 stroke power, and stock is so de-tuned.

I originally bought a PM24ev by the British PM Tuning. I did so because I have a well designed smallframe (PM40ev) exhaust by them, and figured they would be leaders in the fit and performance areas.

The PM24ev is decent, and can be found on ebay for a decent or even 'bargain' price. Worth noting however, you have to buy the exhaust can as additional extra. This is fairly common with expansion chamber exhausts. I bought my can from PM Tuning's online store as to guarantee proper fit, something that can't really be assumed when buying aftermarket parts for obsolete two stroke Italian scooters.

The very sturdy bracket works well enough to attach to the swingarm. It has a black rubber spacer to reduce vibration transfer to the frame.

With the can cost summed with the expansion pipe and hardware, it's around $425 Canadian Pesos all in.

The pros are it's an expansion chamber, so you get that sweet powerband pull which for me is the true joy of a two stroke. Tiny engine displacement but lightening acceleration. Revs higher than stock.
Great welds on thicker steel, reinforcement on weak bits.
Decent instructions, including jetting suggestions and stock carb filter "heart" drilling (makes a small but noticeable difference).
Fairly 'easy' fit with exception of cutting a bit of kickstand off.

The cons are worth noting however.
First, mild steel rusts, so you'll want to spray this heavily with high temp spray paint, which slows you down in terms of testing it out
And before that you'll want to strip the oil off with nasty degreasing solvents like acetone.

The manifold and main chamber body have spring attachments, which is great. Unfortunately mine leaked a thick black ooze due to an easy-fit-but-poor-seal. PM literature, a one-page photocopied piece of paper, suggest using high temp silicone gasket goo, which helps but doesn't solve the issue. Also it adds to the total cost (with the spray paint and acetone) and requires curing before use. I'm not that patient with new hardware and just want to bolt on and go.

The manifold comes with no way to keep from slipping off. I removed the tightening band from the Sito it replaced, and attempted to use that to tighten down the PM on the exhaust stub. Manifold kept slipping off the stub regardless of how over-tightened the band was, likely due to the porky weight of the over-built steel manifold plus gravity plus two stroke exhaust pressure. I bought some stainless plumbing straps of a good size and tried those, and still no luck. I eventually had a MacGuyvered Sito band plus Stainless plumbing strap plus spring hooked from plumbing strap to a hole on my aftermarket cylinder's fin. It mostly held, most of the time.

What every other performance chamber exhaust does is have loops for springs to hook the manifold to cylinder fin holes and/or cylinder shroud screws. The PM even had loops for springs where the manifold and chamber body meet, so it's not like they haven't realized the utility of loops and springs. Weird. If I was to keep this exhaust I'd have a welder add the loops at the exhaust-stub end. It's pretty standard to have and makes accidental slip-off impossible in a very vibration prone environment.

Another con, though more standard for this style of left-hand exit exhaust, is the need to cut a section off the kickstand arm, and to drill a new hole for a spring through the remaining portion.

Finally, this is a loud exhaust. Like Sito loud. Perhaps partly due to imperfect seals even with gasket sealer goo to bot exhaust spigot and slip-joint-with-springs. I thought it might be the can packing though I later discovered the can works fine on another expansion chamber.

So I feel like I'd give this a "7" and for the price, even less. Just IMHO. Decent speed/revs/power much better than stock or Sito. Built like a tank with solid hardware. But frustratingly prone to slipping off the exhaust spigot, black juice leaky, and louder-than-it-should-be compared to similar (and better) exhausts.

For $400+ CAD, I expect better. Especially for a British hand made item. Especially for an exhaust that's been in production this long; the problems this exhaust has have been solved by other companies quite some time ago. I feel the PM Tuning may be eclipsed by the other Euro expansion chambers.

Bittersweet.

Pics forthcoming.
⚠️ Last edited by stimuli on UTC; edited 3 times
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Note the clamps for holding the manifold onto exhaust spigot are all 'me.' Nothing provided. Paul at PM Tuning wasn't helpful either, sending me boilerplate non-resolving response. You can see dripping sludge, high temp grey sealant remnants, lack of spring loops near exhaust stub end, etc.

This is sturdy, just more 'project' than 'exhaust,' and for the asking price, I'd expect a more perfect solution. It's not like Piaggio Vespas were moving targets in terms of build.

You can see my PM24ev smallie exhaust lurking on floor ;D
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⚠️ Last edited by stimuli on UTC; edited 1 time
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Jim Lomas stainless = the business
So I had this feeling the PM was leaving something on the table. I recalled how a VSP2 smallie exhaust I had back in the day looked similar/identical to a PM Tuning smallie exhaust, yet clearly bested it in broad power and higher revs.

I wondered how much better a Jim Lomas (British designed, Czech made) might be. I decided to buy one from their online store, direct from the Czech Republic. The price is decent but they charge a 100 Euros for shipping, which seems exorbitant, but hey it's "two day" shipping.

I purchased a vespa PX125 NG Performance LH BOLT-ON Stainless - Silencer:Stainless Steel from them. The web site mentions they may take a couple weeks to make the exhaust as they work in batches. Fair enough, but if I'm not in a hurry, why the forced 100 euro 2 day shipping? Given exchange rates, I suspect Czech post would be peanuts.

Anyway, I ordered early December, and got it a few weeks ago in January, so "two weeks" my ass. In fairness, COVID, plus Christmas holidays kinda explain that. Again, I wasn't in a hurry, I just felt I was paying the in-a-hurry price for shipment.

When it arrived, it came without the exhaust can. At the time I thought I'd forgotten to order one, or had decided to cheap out and use the PM Tuning can I already had. I just checked today and they totally owe me a can. Hopefully they don't have the balls to charge me shipping.

Anyway, it's a thing of beauty. Like a hornet's stinger. Stainless, pro welds, spring hooks for slip joint and exhaust stub(!), decent mounting hardware. Bolt on and go! I used the PM can which required a bit of elbow grease as the hole/stud spacing is ever so slightly off between PM/Jim Lomas exhausts. Stainless should mean more brittle metal but no rust. With good reinforcement, it should have good longevity.

The first thing I noticed is how much quieter than the PM24ev it replaces was. So the PM exhaust can works great, it's the rest of the PM24ev steel expansion exhaust that is loud. Perhaps the Lomas uses double walls in a few spots too.

It pulls like a coked-up mule and keeps going well past the rpm ceiling of PM Tuning's PM24ev. More power, throughout the entire rev range. I've almost-wheelied on both (PM and Lomas) with just a throttle twist from stand still, but even more so with the Lomas. I wheelied first go.

Other pros include less vibration with the less noise. This is huge and frankly unexpected. My PX feels less like it's falling apart as a result. Way fewer resonant modes and rattles.

This is the exhaust I was looking for. No buyer's remorse. Less peaky means going uphill in third and fourth, as opposed to PM which takes finesse and goes uphill in third. Both will do more than 80 Km/h in third gear (on speedo) but Lomas gets there faster and with more to give.

Cons are: long wait time, exploitative 'two day' shipping that takes 4 days over and above the month it takes to manufacture the exhaust. The shipping makes this a $525 or so exhaust in Canadian dollars. Still likely less than buying the PM from PM Tuning's website, mind, and without any design flaws or performance left on the table(?).

Cons include they forgot to send me a can I paid for. That would suck if I didn't have cans lying around the house already.

Cons/Pros include REALLY tight fitting, which means no leakage and quiet, but a bit challenging to assemble and mount. Took me a while and some grunting.

Springs at exhaust stub end of manifold means no coming off unless I take it off.

Con for noobs is no instructions whatsoever. This includes cutting the kickstand spring arm which isn't an obvious step.

I thought I'd buy direct from Czech instead of ordering from certain German scooter stores, thinking I'd save money. In retrospect, the savings are small and the wait time was huge instead of instant. Also, the Germans would have remembered the exhaust can.
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Not all Dellorto Si24 carbs are equal
I swapped out my Si20 carb for Si24e pretty quick. The Si carbs are ancient and de-tuned under-performing carbs by any standard, which explains why Piaggio used them until the end ;D

They lack a Venturi which is a basic, fundamental feature of a carb, plus the carburetor->carb box->inlet on the engine cases don't match. Plus the carb has a 'filter' on it of dubious value, and it's sealed in a box to keep dirt out. So your scooter has its hands tied behind its back.

Nonetheless, swapping out a 20 and swapping in a 24 isn't very daunting; it's just a matter of detaching the throttle and choke cables and unscrewing two bolts that hold the carburetor in place. Jetting is daunting for a noob, as is setting idle/richness but there're threads galore on these stock carbs. I sort of 'get' Dellort Si carbs so I went with that instead of something more modern/exotic I have no familiarity with.

20->24mm doesn't sound like much but because of Pi*r-squared it's actually a decent upgrade on stockish engines. 314 vs 452 mm2
26e Si are actually 25mm not 26mm, and some say they are harder to jet, so I skipped the road less travelled. I wanted to use others' jetting as a guide.

My first instinct was to buy cheap off eBay as the 'Dellorto' aka Spaco are all Indian replicas these days. Why pay more for the same thing that due to exchange rates should cost peanuts, right?

When my $50 eBay find from a reputable seller arrived I was thrilled. It took me about a week to realize it wasn't going to work properly, after trying screwing and unscrewing mixture and idle screws, swapping out likely jets for less likely jets. It ran as though the choke was on all the time. The slide would stick. The float chamber was stuck and I replaced it with a carb rebuild kit float and needle I had ordered. I spun in the mud trying to lean this thing out and eventually decided this was a quality control reject I had bought.

I went to a popular German online store and ordered a 'DRT Dennis Racing Team' reworked Si24 with enlarged holes for better fuel flow. I assumed Germans check their work and thus the new carb must have passed QC of some kind. The better fuel flow would come in handy as I juiced up my Vespa PX over time.

The DRT 24e Si carb arrived and worked perfectly. Jetting was a breeze and so was setting richness and idle. The crappy previous 24e had made me learn almost all there is to know about these carbs so when I got one that worked it was near instant success.

So I throw this out there as a cautionary tale; I'd recommend a more expensive de-restricted/modified carb as the Dellorto's aren't very good when stock anyway, and modified likely means "scrutinized and tested by capable hands." Carbs that don't work aren't good value for money, and the cheaper they are, the less sense it makes to bother returning them.

If you are curious about the fuel flow mods, google it; these carbs are extremely well understood these days and there's all sorts of small simple fixes to make them better.

Which leads me to... bolting on proper venturis! Whoa! Next post.

If I recall correctly, the 24e Si carb gave more power, revved higher faster. A larger carb seems most noticeable at wide-open-throttle. At part-open, a 24 is the equivalent of a 20, right? At this point I'd already added a lighter flywheel, a BGM 177 bolt-on, and a PM24ev exhaust. I feel it benefited at high rpms. A carb upgrade on it's own likely isn't going to blow your mind, as presumably the carb you have is good for the engine you have. It's when climbing the performance ladder its value starts to show more. You can move more air, thus more fuel, more quickly into the engine. a BGM 177 has more power than a PX200 so I figured a PX200 carb was about right. 24mm is a little bit louder than 20mm, I think.
⚠️ Last edited by stimuli on UTC; edited 1 time
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Venturis for Dellortos
In my view, adding a venturi opening to a Dellorto Si is a game changer. Your fuel economy tanks. But in exchange you get a load more air and fuel into your cylinder per rpm. But let's step back a bit.

That little box your carb is in? It's too short; adding a venturi on top of your carb's air intake would make it 'kiss' the top of the airbox, negating the airflow benefit. So first, a venturi upgrade means a carb box upgrade.

There's two options; a cheaper spacer that goes between the box top and bottom, or an $80 taller plastic top made by Pinasco. Yeesh. Having felt a bit of buyer's remorse going the cheaper route in the past I just went for the taller box top; it seemed easier to seal, maybe less floopy.

Then, for Venturis, there's three choices, an inexpensive ($45 or so?) Polini that also comes with a foam air filter and a 140 main jet(!), a mid priced MRP Racing knock off of a Pinasco, or a $110 Pinasco. Youch. Polini are legit and came with extras so I got that one.

I skipped air filtering and just have the bellows between carb box and under-seat air chamber; I've never taken a look at that stock 'air filter' thing in the past and thought 'wow that's covered in dust.' No regrets so far.

Upon bolting the goodies on, and without the box top on, the first thing I noticed was it was LOUD and I could SEE the air sucking into the engine. I mean I could see the pulses of white condensing vapor as the intake opened. Upon riding I was like WHOA the Del isn't actually an awful carb! Ample power and especially at the top end. Faster throttle response? The Del finally had some balls. All for $45? Made me wonder what the other MRP and Pinascos offered...

The hilarious thing with the Polini on a Si24/24e is that it actually is smaller than the carb diameter. Like it's machined for a 20/20e. And yet it turns the scoot into a turbo charged vaccuum cleaner.

The kit comes with a 140 Main Jet. That's nuts. For reference, a stock PX150 comes with a 105, and with a 24e carb and expansion pipe I was around 116 or so. 140 is HUGE.

It's also necessary. I was actually running LEAN and had a soft sieze on a stretch of highway with a still breaking in BGM cylinder. My sparkplug was chalk-white.

I upped my atomizer to BE4 and Air Correcter to a 55/120 and switched to a b8es spark plug and I finally got the titanium-white off my spark plug. It's spot on chocolate brown now.

In short these venturis, with larger airbox and massive upjetting make the carburettor behave as though it's much larger

The cons of the Polini venturi kit are fuel economy. I imagine riding style has a lot to do with this, but even idling you are pulling in far more air and thus fuel.

The other more glaring con is that with the Polini, you have to remove the venturi to change jets, as it covers them. I think I prefer this to the MRP/Pinasco approach of having holes drilled in the cone of the venturi top allow jet access. That can't be good for flow on those two venturis.

This, plus the fact the YOU WANT TO USE BLUE LOCTITE on the screws (you do NOT want them getting sucked in your engine cases after vibrating loose, which will happen, apparently). It might take a few goes to dial in jetting. Minimum is larger main jet. In my case I had to change the entire stack to get the desired richness on my setup.

The Pinasco airbox works well. They seem to make precise stuff, which makes premium pricing 'worth it' to me if stuff actually fits and does what it is supposed to. I feel like a sucker for buying a piece of plastic for $80USD, but the greater volume plus venturi headroom were worth it in the end. I actually kinda respect the Dellorto now, between the faster flow modifications and the venturi bolted on. It 'feels' like a much larger carb, but still fits inside stockish carb box setups.

Pinasco airbox lid is fiddly/fussy to get started threading with the longer hex screws. You'll need a ball-end hex tool to get the awkward angles tightened on the front-most screw as the airbox top is very close to the upper frame.

Changing to the Lomas exhaust from PM24ev seems to have made my jetting too rich on cold starts, so I'll have to revisit that.
⬆️    About 2 years elapsed    ⬇️
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Necro-ing my thread like a restored vintage Vespa.

I discovered I had cracked engine cases on my PX, I have to assume they were there when I purchased it. The crack became so extreme, the case half with the crack would flex. It dumped all my crank case oil on the ground, ran my gears dry, broke teeth off them (from the flex?). I tossed that set of cases, order new ones from India.

They turned out to be reed-intake. I went with an MRP (or was it MMW?) reed intake, VForce knockoff reeds, and had a Polini CP30 carb. It's great; would recommend. I have the 'dumbo' setup to connect the carb to the frame, as without the air/plenum coming from under the gas tank, it was ear splitting loud, no exaggeration.

Wound up hard-seizing my BGM 177/187 end of last autumn, as the carb needed a clean and would race at idle from dirt in my jets(?). Should have investigated, now regret it.

Bought a Malossi 177 MHR over the winter, with split exhaust port. Bought a balanced reed-only crank with 62mm stroke, had my case half spun out to fit the crank on the flywheel side. Raised the MHR 1.5mm with chunky base gasket, and a 1mm head gasket, to get a 1.1mm squish.

It's now basically two scooters in one.

Below 7k rpm, it's a much torquier Vespa. Keep the revs low and it's not too loud in the neighborhood. Pulls fairly mule-like, mostly due to the crank and cylinder.

Above 7k, it's a ~35HP monster, roughly doubling power every 1k rpm until 9000rpm or so.

It's weird, but I love it. I'll need an even shorter fourth to really make use of fourth gear. I already have a BGM xmas tree with closer gearing, a quite tall primary (22/63 if memory serves). This gives me a first gear that actually does something besides wheelies, a taller second, third the same as stock (my fave gear; I didn't want to mess with it), and fourth shorter (though needs a touch more shortening).

My death machine is for now complete.

Light Flywheel (DC Vape w/ EGIG CNC lighter fan) 1.1kg
JL/SIP Performance 2.0 lefty expansion
MHR 177cc (now 193cc)
62mm crank, balanced, reed-style bell
MRP low-profile stubby reed block, VForce knockoff 8-petal reed.
28mm SmartCarb 2 (no need for fuel pump; sits low on MRP stubby)
BGM fast flow 2.0 fuel tap
BGM chonker clutch
BGM 1,2,3,4 gears. Actually broke a tooth off 4, so stock 4 for now, shorter fourth waiting for engine case to be opened.
BGM xmas tree with 'short third and short fourth'
Tall BGM primary 22/63 (hence the quotes in previous line) to make 1 & 2 do more, 3 the same and short fourth.

I am fairly content, for now.
⚠️ Last edited by stimuli on UTC; edited 2 times
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Pics or it didn't happen
Needs a bigger lithium battery
Needs a bigger lithium battery
Smartcarb, short reed block, light flywheel
Smartcarb, short reed block, light flywheel
Front disc
Front disc
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Hey mate your build sounds and looks amazing.
I'm running very similar to you just the VRONE Malossi cases.

I had originally used the piaggio cases but it just couldn't feed the MHR with that small intake. I was just interested to how you got around that issue. It seems in Asia they just weld a whole aluminium section into that area and extensively machine it down to suit a full size reed intake.
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Sounds like Stimuli has LML cases. Maybe he used one of these with the V Force?

https://www.mrp-racing.de/MRP-Reed-Valve-System-for-LML-engine-case-36mm-complete-set-with-RD350-reed-and-carb-rubber
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Indeed; LML reed intakes cases have great meat on them. Also, random observation, the MHR has some material covering transfers at the base, likely so people don't blow through piaggio cases trying to port match. They thus have a funky angularity to their shape.

You called it Ginch. Also, got a 28mm carb on your suggestion.
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Opened up LML casings. Looks like old BGM -> new MHR port matching in progress. Plus my old engine case.

The LML cases from India were a bit half-baked as you can tell from lack of polishing on cylinder mating surface. Also was missing some studs and dowel.
You can have this case half, only $1000 + shipping. I'll sign it.
You can have this case half, only $1000 + shipping. I'll sign it.
LML cases let you do this.
LML cases let you do this.
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You can still blow through the meat on the LML cases without trying all that hard. Ask me how I know.

Build is looking good. Any video yet so we can hear it in action?

How do you like the SmartCarb? They look really interesting (and CM2 loves his), but they're also a lot of cash, even by high end tuning parts standards.
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Video of Vespa-on-kickstand revving? I can do that in a few days when the rain stops. I don't have a GoPro or anything for ride video.

The SC2 is great. It's fairly compact, and sits nice and low for fuel pump avoidance.

It starts first kick without choke. With choke it ironically takes two or three kicks. The real upshot is no jets, which means no dirt in jets, which means no more piston writeoffs. It's always correct 'jetting' as fuel is metered purely by air intake. I dig it. As to their claims of '10% moar power' and 'moar fuel economy!!!' I can't really say. The Polini CP30 had a touch more power, iirc. It *might* use less fuel, but let's be honest, at 9K RPM it chugs fuel either way. If I want fuel economy I keep the revs lower.

The cable stand-offs are basically maxed out to get correct cable length for proper opening/closing of the slide. Took me a while to notice my slide was only 70% open with more sane stand-off threading.

I just like the peace of mind and absolute lack of talent required to use it.
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Actually, my favorite thing about the SmartCarb2 is the lack of oily fuel leakage. No dripping, ever. At all. The lack of air hoses springing from the carb means it doesn't look Rastafarian either.
⚠️ Last edited by stimuli on UTC; edited 1 time
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We'll take video on the stand.

You need to get an quick pull throttle pulley if you haven't already. Find the one that matches your model, plus a long throttle cable inner and your life will never be the same.

I'll take revving on the stand. And, yeah, I see the advantage of the plug n' play nature of the SmartCarb. I'm a bit of a carb tuning masochist, myself, but will probably give the SmartCarb a shot at some point anyways.
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chandlerman wrote:
You can still blow through the meat on the LML cases without trying all that hard. Ask me how I know.
This for sure. Stimuli you must have got lucky on that casting because many of the LMLs are a bit less than generous in that department.
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Good point Ginch I hadn't realised that they were Lml.
Nice list of parts and I totally agree without having to run a fuel pump.
I do notice that your fuel line runs up and over where it connects to the carb, you may get fuel starvation at higher speed runs but may not notice just sprinting around. Just one to be aware of if something feels off or your temps spike.
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First kick, no choke, cold and rainy. I took a subsequent video but must have muted it when pocketing my phone, plus there was traffic keeping me in check. Will have to make another.
https://youtube.com/shorts/qX0NgdiJoK0
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Funny you should say that Jim, I did have one soft sieze or sudden compression loss going uphill in fourth. Long steep hill/major road. Temps hit 150C and bogged to a stop. Thought I'd written off a piston and/or ring or maybe a reed. Tried to kick it over after a bit but compression was soft. Pushed home.

Took intake off, saw happy reeds, put it back on. Kicked over first kick like nothing happened.

Ironically, blasting in third keeps the engine cool. Like 8500-9000rpm. My timing is variable and super retarded in both metaphorical and literal sense.
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Actually it does have sound
⚠️ Last edited by stimuli on UTC; edited 1 time
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We just can't see it because it's private.
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Fixed hopefully? Edit: YT is being difficult for some reason.
⚠️ Last edited by stimuli on UTC; edited 1 time
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stimuli wrote:
Fixed hopefully?
Now it says it's processing, so something else may be going on. You got the permissions sorted, at least.
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You have ONE JOB, Youtube.

re-uploaded, re-linked. Kinda tame but you get the idea. 1:41 is a bit sporty. My (Grade A repair) speedo or speed sensor is on the fritz; ignore the speedometer. Also note gearing is wildly different from stock (taller 1 and 2).
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Sounds really clean through the whole rev range I like it!
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Gearing looks like this> Bought a 35 tooth fourth by mistake. Got a 36 waiting for next case split.
gearing
gearing
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stimuli wrote:
Gearing looks like this> Bought a 35 tooth fourth by mistake. Got a 36 waiting for next case split.
You mean you don't want to go 85 MPH on your scooter? Razz emoticon
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Not even if I lived on the salt flats of Utah.
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So your low speed cruising is quite rich and burbly. That would be annoying having to chase the revs all the time. You can have them run nice in the lower revs but alot more tuning required. I would say a leaner slide on a normal carb to clean that area up, but the smart carbs don't have the dumb carb technology.
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Could be adjusted withe the clicky thing. First kick no choke suggests richness(?) with current settings.

Given my aspirations (ha ha) I'm leaning (haha) towards richness
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Sounds like it's going towards lean as the rpm gets higher. Does it get hot on a high speed cruise?
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No, stays stable at high rpm. Lugging uphill in fourth (timing, no doubt) builds up heat
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Far as I'm aware smart carb rods are single taper. If it's richer at the lower rpm it would be leaner at higher rpm and about right in the middle.
If it sounds slightly lean and gets hot, there's probably enough clues.
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Hey mate, I ran that same pipe for a while just the Sip variant.
Kind of had a nice whip up onto the pipe and revved out nicely similar to your revs.
The downsides were that although it revved out nicely it never really pulled once it hit the power band. Also like yours it was always really rich and hesitant to run smoothly in the lower revs…hence the feeling that you need to chase it all the time for a pleasant ride.

I'm not dissing that pipe and I'm sure it works on lots of other setups.

Sure that smart carb could be leaning out at higher revs, like Jack said it certainly sounds all light and wooly up there, sounds very lean and dangerous to me.
I run a Sip performance 2.0 now and it really compliments my setup nice low speed running, bags of torque and a nice rev on, nothing silly high just terminating around the 7,500rpm but will allow over rev to around the 8,200
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Agreed the exhaust is holding this scoot back. Never thought I'd say that…

The cylinder and and piston need some window enlargement now that the stroke has changed, too. This is choking higher revs. I was reluctant to do so on a brand new kit, but it's not brand new now. Might widen exhaust ports too.

⚠️ Last edited by stimuli on UTC; edited 1 time
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I think my Jl-direct pipe is a SIP Performance 2.0. Though it looks like a bolt-on-can non-2.0. Hmmm
⚠️ Last edited by stimuli on UTC; edited 1 time
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Jack I may try another 10-15 clicks to the left on the sc2
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stimuli wrote:
I think my Jl-direct pipe is a SIP Performance 2.0. Though it looks like a bolt-on-can non-2.0. Hmmm
Yours is the Sip Original version 1 been around for donkeys. It has sound deadening material spot welded to the inside of the belly section.
The Sip 2.0 has a larger belly section and no sound deadening
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