most cost efficient engine upgrade...

The original 2-stroke Genuine scooter and its 4-stroke manual and automatic offspring

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EvilNerdLord
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Joined: Mon May 27, 2013 9:49 pm
Location: Marysville, CA

most cost efficient engine upgrade...

Post by EvilNerdLord »

Having read and followed all the things folks have done to their stella 150's that just seems to get me more confused about each actually results in....
...how about bottom lining it for me?

So far the Mods I've read most seem to be...

Exhaust, air filter, jet...such as the sito
Exhaust/carb upgrade....pinasco/sito & 21mm carb
full cylinder head/piston w/stock carb & exhaust....like the 165cc kit
full upgrade everything: cylinder/exhaust/carb....

:?:
Last edited by EvilNerdLord on Tue Jul 29, 2014 9:36 pm, edited 1 time in total.
Professional nerd, Cube dweller, and wannabe Evil Overlord (OK, maybe not too evil or lord over more than I can manage...well,­ on second thought make that Suburbanite just trying to make his way in the world as best he can)
djp4059
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Location: Palos Hills, IL

Post by djp4059 »

I've put the Sito+ exhaust on along with a better air filter and upped the main jet to a 95 and the pilot jet to a 42 and I get better acceleration and more power and I'm still getting 108 mpg.
misterbrackets
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Post by misterbrackets »

The most cost effective upgrade is probably just getting a 92 main jet and doing nothing else. (Maybe a more open air filter)

I've had the 165 cylinder in mine for a couple weeks, but I'm still breaking it in so I don't know the extent of its benefits. I can tell that there is an improvement... one more noticeable than when I changed exhausts from the stock to the sito+ (I have the Pinasco exhaust on it now) Installing the cylinder was a fun project and I learned a lot from it.

I love to tinker so it was impossible for me to leave mine stock. (And I bought mine used so no warranty to worry about voiding) I've made plenty of boo-boos but so far I haven't broken anything :)

Right now mine is running great, and last weekend I took care of the two oil leaks resulting from shoddy work on my part installing the 165. (I broke the rubber O-ring gasket on the chain tensioner and tried to reuse a crappy gasket on the clutch cover) Oh, and did I mention that I forgot 2 of the spacers that go between the cylinder and the cyl. head? No, you didn't hear me say that.

However, sometimes I think the most cost efficient upgrade is to do nothing. (Aside from the 92 main jet)
fisher1
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Location: Pa

Post by fisher1 »

An inexpensive improvement can be obtained by using;

1) this exhaust;
http://www.scootermercato.com/Scooter-P ... aust/TEX_1
2) a PX150 air filter
http://www.scootermercato.com/Scooter-P ... ers/131083
3) a 104 main jet and a
4) a 52/140 (2.7)SI Pilot/idle jet

This will "de-restrict" a Stella's breathing in mid- range and increase ability to hold speed on hills and accelerate in traffic. Doesn't offer an increase in top end rpm because it doesn't provide a pipe's ability to improve scavenging at speed. Your main jet requirement may be different due to altitude & differences with individual scoots but you probably will need the SI change to avoid heating up in mid-range.

I wouldn't do any changes on a 2T without first benchmarking your stock CHT temps in various ride conditions and then re-jetting to match those and then keep an eye out for CHT jumps from air leaks at the manifold/ muffler joint which needs re-tightened.

My stock Stella maxed out at 300-310F at speed, I forget what the mid range readings were at sustained 30-40mph ... but they soared after changing the filter and exhaust with the original SI/Pilot.

I seriously think (my thinking can be flawed) that many heat / lean seizures that scoots have are due to exhaust joint leaks that develop months after a new exhaust is installed and peoples' focus on only the main jet. Neither issues can be easily detected without a CHT or EGT.
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