Modern Vespa

That's a lot of riding around and jet changing. As long as your final main jet is under 170 the K98 DQ266 will be ok at the top, where it matters.
Lower down its always a struggle to get lean on the K98 which is why the smaller inner pilot jet.
Any other needles?

I've never been able to run a filter on high RPM motors. I don't know why, but accepted it as a fact years ago.

I love my fuel filters. I use the NCY filters and they catch all kinds of stuff. I've measured flow with and without and there is no difference with the filter. The only reason not to run a filter, IMO, is because you like cleaning your carb.

Yeah, so that's the thing. Testing fuel flow with the bike stationary and the hose in a cup didn't make a difference.

But there's something the test doesn't take into consideration is the resistance from the float valve. I think it's enough to cause a reduction of fuel flow so pockets of air slowly appear in the fuel filter.

Don't have another explanation of why the fuel hose is full of fuel, then after riding, air appears in the hose. Without the fuel filter, doesn't happen.

Of course the biggest effect is WOT and the bike hits a glass ceiling in acceleration.

Yup it's a lot of riding… and changing jets… probably took off the float bowl at least a few hundred times by now.
Most of the time, I didn't even attach the tank to the frame.

Nope no other needles. Didn't see the need as the difference size atomisers took care of 1/8-1/2 throttle.

The taper seems to be sufficient for the engine.

As long as your happy with it. Sounds like it goes as it should.
What size is the main jet now?

Yeah super happy with it… definitely faster than my old Malossi 210. Maybe not top speed but off the line for sure.

And the torque is pretty crazy… goes up hills like they don't exist.

Main is 155. Measured it with pin gauges… it's like a 1.68mm big hole.

That's a drastic difference. If really 168 it's on the limit of that needle/atomiser. Not over the limit but on it.
How high is max rpm?

Yeah measured all the dellorto jets. Numbers don't mean anything. Used to think 148 is 1.48mm but it isn't. Maybe the flow of fuel through it?

Don't have a rev meter, but going on using the old PX sip speedo on the malossi 210 as a comparison, I'm guessing well over 9000rpm. Revs like crazy without hesitation. And going flat out there's no hiccups.

Egig has a dyno chart of the vhsh using a 1.62mm vs 1.86mm jet and without changing anything else. And it's pretty much the same power output. Of course riding stop and go will be terrible. But the point is, that the main jet isn't so sensitive. It's like what it doesn't use just expels through the exhaust. Of course spewing out fuel isn't good and fuel economy will be terrible. But the engine seems pretty forgiving on jetting.

A copy of egig jetting, which he copied from rotax 125 jetting. On the go-karts they don't really need the main jet. The K98 needle binds and blocks it like the smartcarb does with the rods.
Is why the max main jet is 170, after this it barely gets richer, even with no main jet fitted.

If sustained wot, like 10 miles or more, gets hot, then the K98 needs looking at. Otherwise ride it like you stole it.

Does anyone work in fluid dynamics?

I prefer the way the Vape flywheel looks, but engine is getting a bit warm so brought the egig high flow fan.

Thinking about it, are the fan blades actually at the wrong angle with the SIP stock flywheel? They released an updated flywheel which looks like a stock Ducati one.

The Egig is 3cm bigger, but the fan blades do look a little smaller

Put in a new plug and went for a 20km ride. WOT for 500m just before I killed the engine

I actually just put one of those egig fans on my Smallie, too, but have also richened up the jetting, so it's hard to say what made the difference, but I completely agree about the alignment of the blades.

I also noticed the size difference, and while the blades may be lower, they are also longer and a tighter fit to the cowl, so I do believe the net effect is more air flow, I just don't know the best way to objectively measure it.

Yeah, of course I was looking at all smallie flywheels made by independent brands during this time.

All of them seem to have pretty aggressive scoop style fan blade.

Some have super short fan blades, makes me wonder how effective they are.

Forgot to mention the sound was completely different for me… there's a whooshing sound now which goes up and down with the revs.

Super-short as in smaller diameter, or lower profile?

I'll have to go listen and compare, see if I can tell an audible difference. I'll try comparing to one of my largeframe Vape's too, maybe.

Lower profile… some blades barely exist… maybe they're for alu kits??

I don't know if the difference in sound is because the fan is so near the egig kit cooling fins… kinda like whistling through teeth type of thing…

Small updates to the EGIG, just playing around with a few things.

Something Chandlerman might take note too...

Thanks!

I run no-kink fuel line already and other than when I had the quick disconnect, have never had fuel delivery issues even with the giant carb.

I have considered options for minimizing the amount of air that gets heated by the exhaust manifold on its way to the cylinder, but have never really done anything about it. I like your solution, though, and just ordered some heat shielding so I can adopt some variant of it.

I used to run Toyo hoses… but always ended up swapping them out after about a year when they would harden shrink and not be able to bend around things when removing the tank. But I think it's just a matter of time before any hoses shrink.

But wanted to highlight the exhaust shield thought it could be useful on your build.

Edit:
Forgot to mention, I am a little wary of the fact that 10000rpm might blow the heat shield off (even bolted down) to oblivion. Thinking about making something a little more sturdy.

Absolutely, and I greatly appreciate it!

I should be able to get some comparative temps both with and without shielding since it won't arrive until Sunday, but anything to help with cooling is a good thing.

Heat shield arrived and I installed some to prevent blowing hot air off the exhaust manifold over the cylinder.

I used a piece of paper to fabricate a template, then traced that onto the heat shield material and cut it out with scissors.

Dropped and tapped a couple holes to hold it all in place and it's all good-to-go.

I wasn't able to take it for a test ride because I was tight on time and Mr. Biggs wouldn't let me leave, but no rattles or anything rattling at idle.

More to come, but it was easy enough (maybe half an hour of effort) that even if the benefit is nominal, it's not a big deal.

Looking sweet though! Looks the business.

Yeah, that definitely doesn't look like it's going anywhere.

That hole previously isn't insignificant.

With mine, went for a short ride. Seems like the redirected air is now hitting the floor near where the stock junction box is. Where the old manifold would be blocking that space, I have a void.

There's a huge whoosh of air now when I rev the engine on the stand.

I'm thinking if it's worth customising the cowl in that area? Redirect it into the cylinder area again. Hmmmm…

Right, the cowl work can wait, I'll probably end up buying another cowl as an experiment with cuts and using fibreglass to block certain areas off.

But picked up a carbone shock locally for cheap.

And thank goodness I did, didn't realise the old shock was toast. I just thought it was terrible.

Realised red parts on a white bike just look a bit too bodge for me… So out came the silver rattle can…

I generally like the splash of color, but agree it didn't work in this case.

Personally, I'd have gone with black rather than silver so the dirt doesn't show as much, but it looks amazing either way.

I found a splash of orange works well with bikes. I'm boring, so it's the normal black/grey/silver/white for me…

Orange seems to works best with all of those.

So glad I swapped the shock out though.

It's my own fault, I picked up a scrapped shock and thought it'd be better than the stock one, but seems to have totally seized.

The new one isn't anything fancy, but sure hell is better than a fixed rod.

Having a good, working shock is most important. In my aesthetic sense, a splash of color works better on dark colored bikes. I kept all my running gear black or silver on my VBB and let the orange paint speak for itself, similar to what you've done.

You're definitely inspiring me to convert the Smallstate from Fast Rat to just Fast.

It's fun to work on the smallie… glad to have a few guys to bounce some build ideas off as I discover stuff.

Been interesting so far…

I may have glossed over it but what made you go with the VHSH over the SmartCarb? I was tempted to get a SC for this and run my CP24 on the Dio but maybe ill just get a Keihin 28 next time I go to Japan.

I'm just shooting in the dark here, but I'm gonna go with *money*.

Haha damn I somehow got confused cause I thought he was running one previously in this thread.

Ah I think you're thinking of another member with a egig 170, Poindog?

I'm a bit of a traditionalist, I prefer carbs to have a pilot jet and a pointy needle in the throttle.

I just think it's easier to jet with multiple combinations, and there's quite a few people using the vhsh with the 170.

The pwk28 is an awesome carb. But for the 170 I'm tempted to put my old airstriker on it.

Again, I'm not super convinced with meter rod carbs. I think the only person who has made it work better than a traditional carb is the fella with the orange unicorn, CM2.

Oh and maybe this fella… his carb is made by this mad guy in China. Seems to be the real deal…

Oh yeah and this too… lol

Smartcarb is way too expensive for my taste…

However, with the library of jets and needles might balance that total cost out.

Small update to the 50s.

Installed the latest hyper flow fan from EGIG. Sounds a bit over the top, and I was a little sceptical about it, but the fins are pretty big compared to the high flow.

So big the stock fan cover doesn't fit… after a ton of cutting grinding and a bit of paint. It's on. Not super into how it looks, it's not as balanced as a stock cover, hole just looks big.

Don't know scientifically how much cooler it is. But the frame isn't hot to touch anymore. Not sure if it's it's just because weather is 5c degrees cooler.

I put a High Flow on my Smallie at the same time as I went back and re-jetted it and am pretty sure it made a difference. It was about as much bigger than the stock cover as the Ultra Flow is to the High Flow.

So. Much. Flowing.

Of course, now that I know there's an Ultra Flow, I'm tempted to pick one up and see if it helps with the GL, which has always struggled a little bit with temps at sustained 60MPH+.

The High Flow calls for the Electric Start 50S flywheel cover, IIRC. Is that what you're using? I had to space my stock cover out from the cases a couple millimeters to get it to not rub with the high flow.

Lol… a lot of flow… It's starting to sound like something from Spaceballs…

So, don't ask why I have 2 egig fans, but the high flow, worked without any mods on a stock cover… being an idiot with a bit of time on my hands, I installed the latest fan.

So I ended up using a beaten up, red painted stock 50s cover and cut the hole it's not super round, but from a distance, you can't see… I really just wanted to keep the stock cover because I didn't care too much seeing the whole fan and kinda like the last 2 bars of grills at the bottom, even if it affected a little performance. But even after a bunch of hammering with a hammer and dolly, still couldn't make it work, so busted out the grinder.

Yeah at the moment the only place you can get the ultra/hyper flow is from the EGIG site. He's not selling it on SIP/SC yet…

Whole lotta' flowing goin' on.

If/When SC or SIP start carrying to HyperFlow(!!!), I'll probably pick one up. In the meantime, I'll probably just roll with what I've got.

would a flywheel spacer create enough clearance for the fan? https://www.sip-scootershop.com/en/product/spacer-crimaz-flywheel-cover-th-3mm_22159600

It absolutely would. My washers space the cover out about 2mm, to that would give me a millimeter to spare. I'll either get a spacer or the taller 50 Special cover at some point. As long as it's a rat bike, though, washers and some tape around the gap are doing just fine.

Not 100% sure, I'd guess yes, but something tells me the "knuckles" on the flywheel still might not clear, even with extra space…

They're quite tall

I had to install a Crimaz flywheel spacer on my PK after i installed a Vape it. I've always been pretty disappointed with the smallish blades on the Vape fans. I didn't know there were cooler ones out there. I'm pretty sure SIP sells a few different thicknesses. I suppose double stacking flywheel spacers could also be done. I probably wouldn't buy an aluminum spacer since i would probably accidentally bend it at some point.

Thought someone would never ask… lol

Yeah there's quite a few fan designs for the vape and smallframe engines.

Even SIP tried to update their own fan from out of the box.

"YGROS RACE by VAPE" do one too.


Think KR Automation do one as well. I actually asked them (and Egig) if they had any kind of recording or temperature chart - ie proof - that their products were actually any better than the vanilla kind. Neither of them did. Hard to swallow some of the hype (pun intended) without clear evidence.

Just looking at your stick-on heat shield 108, the lip it creates doesn't seem like much but if there is a lot of flow coming through a small area then anything will upset it. What about using sheet metal to direct flow, and put the heatshield outside the duct instead? My mate did the first bit on a LF some years ago, he said it made a discernible difference but unfortunately changed a jet at the same time. So...

The other thing that may have an effect is how tight the shroud is to the blades. Some have quite a large gap, and I think in water pumps at least that has a negative effect.