NQ50 Spree intake mod / porting. Need get quicker take off.

mmaannyy · Post by **mmaannyy** » Sat May 09, 2009 5:04 pm

Trying to get my 86 Spree across the intersection quicker.
Porting the intake manifold.

Does this look right?
Will I need a larger Jet?
How does one use the search option, is there an aesy way to use it?
I come up with too many results.
I thought pictures were posted on intake porting.

Kenny_McCormic · Post by **Kenny_McCormic** » Sat May 09, 2009 5:48 pm

Looks good from the pic you posted, you will not need a larger jet.

Post by **noiseguy** » Sat May 09, 2009 10:13 pm

Ahh, check the porting you did against the thermal decoupler (brown piece.) It looks like you went too far in enlarging the opening. If so, the new opening will be larger than the o-ring, which is bad and will cause a leak.

The goal isn't to enlarge the opening, but to get a better transition into the rest of the manifold.

toboggan · Post by **toboggan** » Sat May 09, 2009 10:17 pm

hmm. while my engines alreadt torn apart, i think i might do this!

mmaannyy · Post by **mmaannyy** » Mon May 11, 2009 11:05 pm

Checked my porting job today.
O-ring is to the most outer edge.
There is no vacuum leak.
Went for a road test, no noticeable gain in acceleration nor top speed.

Spreetard · Post by **Spreetard** » Tue May 12, 2009 1:35 am

my intake is a bit more oversized than yours, and i can tell you, it made a good difference BUT...

0mph thru 10mph+nq50=*.
10-30mph...different story. it's like the bus in "speed"; stay above 10mph, and your good. drop below or stop, and my only suggestion i KNOW will work is redbull and running shoes. or a dio engine. i opted for redbull. though exhaust port work would help, i suggest you refine your grinding skills first. it's alot easier to screw up than the intake, after all...

Post by **noiseguy** » Tue May 12, 2009 6:51 am

Spreetard wrote:my intake is a bit more oversized than yours, and i can tell you, it made a good difference BUT...

I assume you've modified the pulley as well, then? What kind of RPM are you pulling on the engine?

Have you gone through the head and modified it to get the squish down to .020"?

Spreetard · Post by **Spreetard** » Tue May 12, 2009 10:45 am

i've actually left the pully stock better take-off.my rpm is currently unknown, but i know it revs consiterably higher than stock, sometimes it starts to sound a little scary

i'm still trying to find someone to mill the head around here, i just don't trust my belt sander to be presice or flat. you said something about an 84/85' head being similar??
MORE POWAH!!!

Post by **noiseguy** » Tue May 12, 2009 12:57 pm

If you don't have access to a mill, you should try installing the '84/85 head. They're cheap; just check the squish clearance with some solder.

You should remove a bit from your pulley; you only need a little bit (.04" or so) to get an improvement.

Spreetard · Post by **Spreetard** » Tue May 12, 2009 3:51 pm

how much would the pully mod affect my takeoff? i mostly have been attempting to go quicker, not faster. my ped already exeeds the max legal speed in michigan, granted not by much, but as it sits it's pretty peppy...for a spree

i already can't top out @ the 1/8 mile dragstrip, so my main focus is getting it up to speed a little faster. i've got an extra 86' spree, my future dio rocket, and that'll be the top speed machine. the 87' is more an experement in two-cycle tinkering, my first such venture.

i'm also working on an old mac90 competition go kart engine, if i can revive it i'll prolly' weld up an extended swingarm for one of the ol' spree frames and call it a drag ped(should be scaryfast) or mabe i'll drop it in the 60's schwinn minibike frame sitting out back.
*sigh*so many toys, so little time

Kenny_McCormic · Post by **Kenny_McCormic** » Tue May 12, 2009 6:22 pm

Trust me, the cops in Michigan(the ones that know peds are supposed to be 30mph max) DGAF.

Post by **noiseguy** » Tue May 12, 2009 9:03 pm

Spreetard wrote:how much would the pully mod affect my takeoff? i mostly have been attempting to go quicker, not faster. i already can't top out @ the 1/8 mile dragstrip, so my main focus is getting it up to speed a little faster.

OK, then you can go the other way and shim out the pulley a bit (again, we're talking about 0.04 at a time) so that you hit the 1/8 mile line at top RPM. There's a thin washer behind the pulley called the thrust washer, go to Honda and get a couple, they make good spacers for this.

Spreetard · Post by **Spreetard** » Tue May 12, 2009 10:55 pm

in that case, i'll do the standard pully mod, then just re-shim at the track.
manual variator

i guess it's better than stock. i also started cutting out the clutch case for cooling, as my clutch is a pretty blue color from off-road missions. sadly this will mark the end of my extreme offroad adventures- sand and open clutch dont mix

as soon as i get batteries for my camera, i'll post up pics of my Spreetardtmand of the various mods, especially the monster intake. it's the third one i've ground out for my scoot,very thin walls

and polished on the inside with a brass brush

i tend to go a little overboard sometimes, wanted to see just HOW big a stock intake could go.

is there any way to put sb50 reeds under my existing intake?i know they are very similar,but would it work??!?

Spreetard · Post by **Spreetard** » Tue May 12, 2009 10:59 pm

sidenote; how do you put a little "tm"on something??!?
quote: "Spreetardtmand" EPIC FAIL!

Post by **noiseguy** » Wed May 13, 2009 2:20 am

SB50 reeds are a drop in, but should be the same size as your current '87 reeds from what I'm told.

If you get a non-kickstart sidecover, you can remove all the cover except the bit that holds the starter pinion in place. Easy pulley mods and good ventilation.