Post big bore tuning+all my Newb questions

Does your Spree/Elite already run great, and you're trying to make it quicker/faster? Need a monster motor swap? Discuss your ideas here.

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Jonadz
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Post big bore tuning+all my Newb questions

Post by Jonadz »

Seeking advice! I know I know should have done a motor swap but I pulled the trigger before consulting here.
It's an 85 spree with 48mm bbk, three 1in holes drilled in air box with one and a half covered with electrical tape currently. After market plug wire and ignition due to original baking and breaking. Currently running the last of a 50:1 premix. Should I wait until I swap to an 80:1-96:1 mix before attempting to tune because this this is killing me. Just filled with a 90:1 last night and is impossible to tune. Have the throttle needle at 3rd notch for first "lean setting but can't seem to actually lean it out, idle screw doesn't do jack either unless I begin to open it the scoot dies. Have to keep it completely seated to maintain an idle.
Throttle seems slightly sluggish on takeoff, around 15mph the hamster wheel gets to spinning pretty good but about 25mph I'm screaming loudly down the road with no more gain! Any quick pointers I'm overlooking?
Last edited by Jonadz on Thu Jun 01, 2017 11:52 am, edited 1 time in total.
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Re: Post big bore tuning

Post by Jonadz »

Best possible plug reading I could get was WOT and darn near doing a front flip after killing the engine and slamming both breaks, should my color be slightly darker or is this fine?
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Jonadz
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Re: Post big bore tuning

Post by Jonadz »

Compression is reading about or above 120
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Wheelman-111
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Re: Post big bore tuning

Post by Wheelman-111 »

Greetings:

That plug looks good to me. You could be more confident with a CHT gauge giving real-time feedback.
Changing the amount of oil in your mixture will affect tuning and jetting, as you've surmised.
The majority of built-engine tuners run 32:1 oil. I've seen posts from people using a lot less oil, but they seem to post once or twice and disappear. Can you think of a possible reason?

Top speed on the Spree is entirely RPM dependent. Assuming it makes good power to begin with (and based on your lack of take-off I'm not so sure it does...) the hard ceiling will be determined by overall gearing and how high it can rev. For various reasons, small ports, etc., the Spree block is more Bass than Soprano. You can fit a 2.75" tire and see about getting Taz's one-tooth bigger gear.
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Re: Post big bore tuning

Post by eclark5483 »

I'm assuming you're still using the pump. Do this... order a #80 main jet and swap that into it, then run it at 96:1 in the tank (with pump). You are probably way too rich on the fuel which is why the mix screw does nothing. After a swap, you can set that needle back to normal and you should be just right for your mix at about 1 and 7/8ths turns out. Plug looks good, but you want it a bit leaner oil on acceleration for a better take off then enriched at higher throttle
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Re: Post big bore tuning

Post by Jonadz »

Forgot to mention previously that I am running a 2.75 on the rear. As well as during break in at the beggining I had tons more get up and go, also hit 40 at half throttle.... Feel like break in almost broke it now with less power and a ton more obnoxious noise. I know my jet number was wrong when I previously mentioned it being a 90 in another post and found I have either an 80 or 85 in it. Will have to check again when I get home.
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Re: Post big bore tuning

Post by Jonadz »

And yes sir still using the pump per your previous advice.
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eclark5483
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Re: Post big bore tuning

Post by eclark5483 »

So when you say more obnoxious noise. This started happening after break in? That kind of raises my curiosity and concern a bit.
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Re: Post big bore tuning

Post by Wheelman-111 »

Greetings:

Shame on me for not reading thoroughly. With the pump, anything around 1% (96:1) should be fine.
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Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
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Re: Post big bore tuning

Post by Jonadz »

Obnoxious noise as in around 8grand (just an estimate without having a tach) sounds like the piston wants to shoot out of the jug! Started with kit and just seemed to get louder with more miles put on it.

Wheelman, no shame, I don't think I remembered to include I was still using the pump in my first post.
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Re: Post big bore tuning

Post by Jonadz »

Upon installation I thought it sounded like the piston was hitting the head at higher rpms but after break down numerous times I Havnt seen any damage.
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eclark5483
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Re: Post big bore tuning

Post by eclark5483 »

Just makes me wonder if your crank might be loose or something. Might just be the reeds tapping out as well. 8,000 is about the max RPM your gonna get with a stock pipe. On an 85, your talking around 30-32mph. The 85 has a 12T gear so combine that with a stock pipe, your really pushing it at 8000.
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Re: Post big bore tuning

Post by Jonadz »

8k was just a number I threw out, may not be accurate, could be more like 5.
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Re: Post big bore tuning

Post by jakubman1 »

Did you seize it yet?
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Re: Post big bore tuning

Post by Jonadz »

I did have a soft sieze about 40 miles ago, I was getting a little over excited, it started right back up and Havnt had one since.
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