Vespa ET2 DR Evo 70cc upgrade
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Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Thu Apr 19, 2012 3:37 pm quote
Here is a link to my post about the upgrade on my blog:
http://xantufrog-vespas.blogspot.com/2012/04/dr-evolution-70cc-upgrade-for-et2.html

I have this cast iron kit paired with a Leo Vince SP3 exhaust and my first impressions are very very favorable. Enjoy!
Molto Verboso
Joined: 05 Apr 2010
Posts: 1917

Fri Apr 20, 2012 5:27 am quote
Sweet !
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Wed May 02, 2012 3:48 pm quote
first update: on first tank of gas with the 70cc kit I got about 49mpg! While this is worse than I used to get when completely stock (~56mpg), it's actually better than I was getting with the SP3 pipe alone on the 50cc cylinder. This tells me the pipe may be the bigger contributor to the fuel economy hit. This fuel economy is pleasing as well given that it was a break-in on the new cylinder. The flip side of this, of course, is that I wasn't riding full throttle during this tank for break-in purposes. However, I frequently hit about 40 miles per hour, which used to be near my top speed with just the SP3. So the numbers are still pleasing: going the same speed I used to, I get better fuel economy than with just a performance pipe on the stock cylinder.

I'll update my blog with this info as well as initial top-speed results later this week.
Member
'06 LX70 2T
Joined: 28 Apr 2012
Posts: 20
Location: London
Fri May 04, 2012 10:11 am quote
Nice one!

I'm about to do the exact same mod, although the DR70 cilinder I received from revolution70 today has been ported for extra performance.

Ordered a Sito+ from Italy as well, so am looking forward to similar performance to yours..... you mentioned a 74mm jet, sounds slightly lean to me according to the instructions from revolution70 (78-88 jet recommended)

Did you put different weights in the variator?

Bart
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Fri May 04, 2012 12:23 pm quote
Hi,
I am using lighter rollers, yes - 5.6gram (down from I think 6.7 stock for my late model variator). These rollers came with the SP3 pipe. I am probably going to play with slightly lighter and slightly heavier.

74 is smaller than some on here, like Fabio Dougie use(d), but it was recommended to me as a starting point by several other users with similar mods on their ET2 and Typhoon. I can tell you it is definitely not lean at most throttle positions - even a llittle rich. But I haven't really tested WOT yet due to break-in period - from brief stints above 3/4 throttle I do get a fair bog down in power, but my sense is it is a running rich bog (my filter is over-oiled and needs to be redone, so this might be part of it). I am going to test this with plug chops and playing around with jetting tomorrow, so I'll let you know for sure. This is with a 17.5mm PHVA, by the way - the jet size would be much bigger on a 12mm weber (probably near 8.

I hope this helps - all I can really say at this point is it's a "starting point" tuning that won't blow your engine up. Hoping to home in on optimal tuning soon.
Turnkey 79
2 helmets, 2 jackets, 4 spark plugs, 2 rear bulbs, some bolts, a spring, an ET rear rack, clear indicators and half a can of unleaded, but no bike!
Joined: 14 Jan 2011
Posts: 3646
Location: The British Countryside
Fri May 04, 2012 1:51 pm quote
Good reading froggy, cheers!
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Sat May 05, 2012 2:15 pm quote
Well, a couple of updates:
1) yes, 74 is too lean for the kit+pipe. Although my mixture was good through the midrange, I discovered that going to a larger main jet was what made the full throttle bog go away. So, if you have a Sito+ or SP3 pipe, and it is derestricted, use something bigger than a 74 main. The next size I had was an 82. The power felt a wee bit "soft" so I think an 80 might serve better. But really, I'd start at an 84 on a given bike and work backwards carefully.

2) top speed: with the 82 and 84 main my top speed was about 47-48mph indicated. This was reliably reached on a flat, and I'm pretty happy with this.

3) I soft-seized. VERY disappointed - break my brand new top end. I do not believe the soft-seize was due to mixture being too lean - plug color was very good and I was running the 82 main at the time. I think I snagged a ring on the ports... appears my first try at chamfering was not up to snuff . Also, I was doing this after a 100 mile break-in period (as opposed to the 200+ mile period suggested by the manufacturer. Bad chamfering, high heat, and an insufficient break-in period.
Let my tale be a warning.

Next step is to find someone with a ball hone, and get my hands on some fresh rings I guess.
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Sat May 05, 2012 2:23 pm quote
I've update my blog to reflect these experiences
Hooked
ET2
Joined: 27 Dec 2010
Posts: 121
Location: Was Galway, Ireland and now London
Sun May 06, 2012 3:54 am quote
xantufrog wrote:
3) I soft-seized. VERY disappointed - break my brand new top end. I do not believe the soft-seize was due to mixture being too lean - plug color was very good and I was running the 82 main at the time. I think I snagged a ring on the ports... appears my first try at chamfering was not up to snuff . Also, I was doing this after a 100 mile break-in period (as opposed to the 200+ mile period suggested by the manufacturer. Bad chamfering, high heat, and an insufficient break-in period.
Let my tale be a warning.
Why chamfer at all? Are ports not supposed to have a proper edge?
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Sun May 06, 2012 5:37 am quote
Chamfering may not be necessary - it is strongly recommended as a must by mechanics on this site (Greasy, Motorsport Scooters folks, etc), so I did it. However, my old Piaggio stock cylinder has no evidence of chamfering that I can see.

Last night I ordered a Flex Hone / ball hone to clean up my bore - the benefit of this is the balls will ride into my chamfering a little and should soften any edges or irregularities I left (or introduced). Also ordered some new rings, and some other goodies like different weights and contrast springs to try
Hooked
ET2
Joined: 27 Dec 2010
Posts: 121
Location: Was Galway, Ireland and now London
Sun May 06, 2012 1:25 pm quote
xantufrog wrote:
Chamfering may not be necessary - it is strongly recommended as a must by mechanics on this site (Greasy, Motorsport Scooters folks, etc), so I did it. However, my old Piaggio stock cylinder has no evidence of chamfering that I can see.
Fair enough. The book i have so far based all the tuning of my ET2 on is Two-Stroke performance tuning by A. Graham Bell, and that makes little mention of chamfering. I can see it being a case on older engines that have flaws in the casting but i struggle to see why its necessary on a newer bores.

It really sucks that it happened to you though! I hope you get it sorted quickly.

Good luck with the project, my ET currently does about 70mph flat out, and i think i'm reaching the reliable limit for a air cooled set up. Next step is water cooling
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Sun May 06, 2012 4:25 pm quote
70mph! Care to fill us in again on the details of your setup??
Hooked
ET2
Joined: 27 Dec 2010
Posts: 121
Location: Was Galway, Ireland and now London
Mon May 07, 2012 1:05 am quote
The kit is a 70cc polini corsa(an iron kit), and exhaust is a Yasuni City 16. I have 3.8g roller weights in a standard variator, and a polini kevlar belt. Clutch springs are standard, i don't want it to be snatchy on take off as it would annoy me. There is also a polini Primary gear up kit and it has malossi high flow foam in a standard airbox.

I do have to admit, 70 is a max figure when your fully tucked in and a tiny fly screen to aid aerodynamics. It wouldn't do this when your sitting up! So i guess i did exaggerate a little bit, sorry. Couldn't resist

I think it currently has about 9bhp at the back wheel, but as i am no longer living in a house where i can build my own dyno, i will have to wait until i can do that to see some accurate figures.

If you wanted mental speed, you could install a primary and secondary kit, single ring aluminum cylinder kit, high speed variator, 21mm carb, racing crank and a proper racing exhaust. This would not be even slightly road legal, but would be mega powerful(maybe 18bhp?) and would have the possibility of <85mph. But this would be VERY unreliable.

The great thing abut the et2 is it uses piaggios short engine case, which is a universal part even between the liquid and air cooled engines. and seeing as countries such as Italy and Spain have racing series for scooters with this engine casing, there is a never ending amount of possible modifications really.

Though, i do have to point out a few downsides. I am slight danger of snapping my crank, and it drinks fuel like you wouldn't believe. 40 miles to a tank, less if i go flat out everywhere. Its also super loud which i happen to enjoy but i know its not everyones cup of tea. Its also a good bit more unreliable than it once was.

Alex
Member
'06 LX70 2T
Joined: 28 Apr 2012
Posts: 20
Location: London
Mon May 07, 2012 2:13 am quote
xantufrog wrote:
Well, a couple of updates:

3) I soft-seized. VERY disappointed - break my brand new top end. I do not believe the soft-seize was due to mixture being too lean - plug color was very good and I was running the 82 main at the time. I think I snagged a ring on the ports... appears my first try at chamfering was not up to snuff . Also, I was doing this after a 100 mile break-in period (as opposed to the 200+ mile period suggested by the manufacturer. Bad chamfering, high heat, and an insufficient break-in period.
Let my tale be a warning.

Next step is to find someone with a ball hone, and get my hands on some fresh rings I guess.
That's a shame... slightly wary of that happening to me as well.... I'm not going to chamfer the ports so will keep you posted on results with that. If the cilinder doesn't seize I expect the crank bearing to give at one stage actually, bu we'll deal with that as and when
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Mon May 07, 2012 4:12 am quote
Thanks for the specs Alexander!
For me I wasn't really looking for more than 50mph - that's what my P200 is for. But I was looking for more grunt on hills and around town for my wife and I riding 2-up. I can say the DR Evo fits this bill very well (until you snag a ring )
Hooked
ET2
Joined: 27 Dec 2010
Posts: 121
Location: Was Galway, Ireland and now London
Mon May 07, 2012 7:02 am quote
xantufrog wrote:
Thanks for the specs Alexander!
For me I wasn't really looking for more than 50mph - that's what my P200 is for. But I was looking for more grunt on hills and around town for my wife and I riding 2-up. I can say the DR Evo fits this bill very well (until you snag a ring )
No problem . It sounds like you have exactly what you need so, the pipe you have is good for that too, its a very good pipe for getting a little more torque at lower(read: less antisocial ) revs. I would recommend getting some high flow foam for the standard airbox though, just so you can make the most of your now free flowing pipe!
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Thu May 10, 2012 6:20 pm quote
Honed the bore today and put new rings in... thing still has no compression (~100 psi). I'm extremely surprised, the scoring wasn't that bad.
Member
'06 LX70 2T
Joined: 28 Apr 2012
Posts: 20
Location: London
Mon May 14, 2012 4:10 am quote
Hi guys, completed my dr70rpm + Sito Plus upgrade this weekend. It's doing approx 46mph flat out... am slightly disappointed as I was hoping for 50mph+

I'm using an 82jet and took the brass diffuser out of the carburetor intake (it's round to fit in the intake side of the carb with round holes in it).

Plug chop shows slightly lean!? and when it's cold it will barely rev. (WOT only gets a rev-limiter like stutter going)

I definitely need to adjust idle mix&revs as well as the needle (it bogs at half throttle). On top of that I've ordered 80-102 sized jets.

Idle settings I've got covered, but does anyone have an image that shows how to adjust the needle?

Thanks gents.
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Mon May 14, 2012 4:18 am quote
Here's Fabio's nice intro to tuning the carbs:
2-Stroke Carburetor Set-up Technique

I was hitting 48mph full throttle on a flat with the 82 and 84 mains. Then I soft-seized at mid-throttle But 46 sounds reasonable - I don't know how husky you are, but I'm a pretty small fellow, so I could see my figure being 46 with a few more pounds


Did you touch your rollers? Too light might have you hitting your peak power a wee bit too early and reducing your top speed.


I have a malossi 70cc coming in the mail - ordered it professionally chamfered from Motorsport Scooters. Not in the mood to pay $40 for a rebore plus 40 for an oversized piston and rings plus shipping from europe all for a kit which was only $100 to begin with... I'll update on my experience jetting and riding the malossi (and how the top speed compares to the DR).
Member
'06 LX70 2T
Joined: 28 Apr 2012
Posts: 20
Location: London
Tue May 15, 2012 5:55 am quote
Thanks!

Yes that carb set-up guide is good, I read that before doing the swap. It doesn't show how to do the needle though?

Not that husky, but 92kg @ 1m90 tall so I guess that doesn't make it go any faster

Rollers are untouched, it doesn't seem to need anything done to it, but when the engine is all done and set-up I might try a few different weights.

Fair enough on the Malossi cilinder! Keen to hear how that runs.
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Tue May 15, 2012 6:48 am quote
What you do to adjust the needle position is unhook the throttle cable from the throttle slide. This allows you to lift a little plastic bit out of the inside of the throttle slide - the needle sits underneath. The needle has a bunch of grooves on it, and a little metal clip. You can pop the clip off and snap it around one of the other grooves if desired. All the clip does is limit how far down the needle sticks into the main jet at a given throttle position. If you set the clip lower on the needle, it holds the needle higher out of the main jet (richer). If you set the clip higher on the needle, the needle sticks deeper in to the main jet (leaner). Hope this helps!
Member
'06 LX70 2T
Joined: 28 Apr 2012
Posts: 20
Location: London
Tue May 15, 2012 1:31 pm quote
Thanks! I'll try to finish my setup tomorrow when I should have my 80+ jet set in the post as well
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Fri May 18, 2012 4:40 pm quote
Got the malossi sport today. It is now on the scooter but not everything is fully hooked up. I'm not overly impressed with the casting - it doesn't look superior to the DR Evo (which you would hope to see, given it is considerably more expensive). In fact, I though the head looked a wee bit finer on the DR. But it looks well-built nonetheless, and I much prefer the o-ring seal the Malossi uses on the head to the aluminum gasket the DR uses. I look forward to getting the scooter back on the road tomorrow.
Member
'06 LX70 2T
Joined: 28 Apr 2012
Posts: 20
Location: London
Mon May 28, 2012 6:37 am quote
How's the new setup? Power vs. DR EVO?

I didn't finish my carb setup yet so mid-range is choppy. I'm nervous that it's too lean but my better half wanted to go for a ride with the nice weather here so I thought I'd risk it....

If it doesn't want to rev when cold, do you think it's running too lean or too rich?
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Mon May 28, 2012 6:53 am quote
Cavolonero wrote:
mid-range is choppy. I'm nervous that it's too lean
Pop that needle up higher (lower the clip) and try again! I'm convinced my softseize happened from a lean needle position at this point.

I've got a Polini 70cc sport on there now - had some issues with the Malossi (user issues). The Polini is nicely finished and appears to be very fast... I'm going to be VERY careful with jetting and break-in on this kit so I don't waste money so I can't say for sure. It's a little more peaky in power than the DR Evo, as would be expected given its higher optimal RPM range. It is hard to keep UNDER 30mph. Overall... I think the DR Evo was my preferred kit until I broke it because it had a power delivery which was more "even" and "grunty".

I want to say trouble revving when cold could mean a little rich - my logic being that when it is hotter combustion will happen more easily from temperature and your compression will be higher and this overcomes the cool jetting. But... I'd get some more opinions and look at the plugs before going leaner. For example I know that really lean can lead to revving problems too.

...in fact, since your "revving" is coming probably from opening the throttle into the mid-range... I guess I'd be inclined to richen the needle to satisfy your concern of being lean there first. Maybe it will help the cold revving issue too. If nothing else, it's the safer direction to try the jetting. You can always go leaner after having tried richer. Might not get the chance if you try leaner first and it's the wrong direction

What is your jetting right now?
Lurker
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Joined: 01 Sep 2011
Posts: 1
Location: California Central Coast
Wed Jul 25, 2012 9:49 am quote
I have read your blog and some of the links with great interest. I am kitting out my Typhoon 50. I want better top speed and slightly better pulling power. Acceleration is not critical. Acceleration with the stock setup is OK for my purposes. But I need to pull hills a little better and would like to hit 45 on the flat a little easier.

So, I am looking at the DR Evo kit, new jets, 6g rollers, air filter and a new belt. Bike currently has 4500 miles on it. Probably need to replace the belt no matter what. Might as well do the rollers while I am there.

So, my questions is this: would you buy the DR kit again? If so, would you leave the chamfering to a pro or not chamfer the ports at all?

Any updates you have on jets may be helpful, too.

TIA,
BIll
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8129
Location: Atlanta, GA
Thu Jul 26, 2012 4:57 am quote
Hello! I actually would definitely buy it again. And, in fact, I've come to the conclusion my chamfering was just fine. I got a kit "professionally chamfered" and I had done at least as well with my job on the DR. Based on scoring I observed around the piston and on subsequent rebuilds even with really rich jetting, the seizure was probably due to lack of lubrication (and not observing a long enough break-in period. Be sure to increase the oil metering rate with the kit... you've added 50% more displacement... you'd better pump more oil.

I have now tried the Malossi cast iron 70cc and the Polini cast iron sport 70cc as well.
Of the 3, the DR and Polini have the nicest casting by far. Malossi I was disappointed with the casting.
The Polini is probably the "best" of the 3, but its peak power comes at higher RPMs than the SP3 pipe I am running, and therefore isn't a great match... don't really experience more top speed over the DR kit because of it. I think you want a higher-revving pipe to experience the full joy of the Polini.

So, with the stock pipe or an SP3, I suspect the Polini and DR are about = performers, but the DR is much cheaper.

A couple of notes: the Malossi and Polini come with upgraded reeds and o-ring sealed heads. This is nice and something the DR lacks (but may not need either). The Malossi comes with a reinforced wrist-pin bearing. This is a very nice inclusion, and may result in longer road time, as I suspect all 3 kits are hard on the stock bearings.

Interestingly, the DR has a significantly larger bore than the Malossi and Polini... why this is I am not sure. I figured "well, logically the piston must stick forward more to = the same displacement as the other kits", but that doesn't appear to be the case. I think the DR is in fact slightly larger displacement. I think the power in the Malossi and Polini kits comes more from aggressive porting.

The DR has significantly thicker rings. I don't know really what this means, but might mean better longevity and less risk of the rings breaking.


All of these details aside, whatever kit you buy is going to turn your scooter into a really strong machine. I have actually gone BACK to the DR - gave it a good hone and slapped some new rings in. I'm having trouble jetting it right still... pain. But it runs well enough except in the very low throttle ranges.
Hooked
'79 - V90 =//= 2005 - ET2
Joined: 05 Sep 2019
Posts: 104
Location: Brooklyn, New York
Sat Oct 24, 2020 4:46 pm quote
DR70cc Oil Pump vs Premix
So after reading this thread over a couple of times, Reading about a soft seize, assuming everyone is running the oil pump only and no additional oil in the fuel tank. Whats best with the DR70 Evo kit? Can the oil pump keep up with this kit? Is the stock pump adjustable? Or is it best to mix a good oil w/your fuel?

Cheers


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