Re-jet or replace stock intake?

[Melchior]

Hello all,

I've been trolling this site for awhile now trying to learn as much as possible about my 84 spree. That being said, I've discovered the source of my spree's problems:

My carb is not connected to my airbox; i lack the bendy pipe that bridges the gap. So, I'm running lean.

Solutions: Find a snorkel to bridge the gap or re-jet and get a replacement filter.

I've found the stock parts I need locally but wouldn't mind having a little boost.

Rejetting: I've seen the UNI clamp-on filters and have read a few post regarding them. I understand the argument of "What goes in easy, must come out easier.", but without any intake restriction I'm still going 25-30mph (@ 240lbs of big n' tall) which seems to be the standard.

I'm no expert, but wouldn't adding restriction only lessen the need for re-jetting?

What should I do fellas? Do I have any other options?

Thanks,
Melchior

[devenex]

Drop the ~$12 on the tube, uni filters on sprees just don't usually work out well.

[Lunytune]

but without any intake restriction I'm still going 25-30mph (@ 240lbs of big n' tall) which seems to be the standard.

What a coincidence, we are physical twins, 240lb big n' tall 6'0". 30mph is about all I can get out of my wife's SB50, mechanical twin to the Spree. She can get 32, being a few pounds (but not many) lighter and shorter, 5'2".

Dabbling with air intake is admittedly voodoo science. Best to just restore to OEM. Going with Tazland's 44mm overbore (putting it to 57cc), you might go to 78 jet. I believe standard is 68. But when you do that, watch the color of your plug. You don't want white or gray, too lean. You want a chocolate brown. Black would be too rich.

The overbore may not increase speed, but should increase torque.

[Melchior]

Hey, thanks!

Looks like im staying stock for now. I plan on calling my local parts people today and ordering the tube and filter as everything else seems to be in place. After that, I suppose I'll clean out my exhaust just to see what happens. A new "extended high-speed" plug is in need aswell. These tempermental little engines...

Sorry Lunytune, no overbore for me; I barely have the space and tools to clean my carb let-alone major surgery. I suppose you experience the same looks of disbelief when you zoom by on a weed-wacker as I do!

Anyhoo - Thanks again fellas! When I'm finished with everything I'll get some pics to show off.

Melchior

[Lunytune]

I suppose you experience the same looks of disbelief when you zoom by on a weed-wacker as I do!

I don't know what kind of looks you receive. We live in a small town (4000) and have been high profile for many years. Our recent romance with the scooters is the talk of the town.

[Bear45-70]

but without any intake restriction I'm still going 25-30mph (@ 240lbs of big n' tall) which seems to be the standard.

What a coincidence, we are physical twins, 240lb big n' tall 6'0". 30mph is about all I can get out of my wife's SB50, mechanical twin to the Spree. She can get 32, being a few pounds (but not many) lighter and shorter, 5'2".

Dabbling with air intake is admittedly voodoo science. Best to just restore to OEM. Going with Tazland's 44mm overbore (putting it to 57cc), you might go to 78 jet. I believe standard is 68. But when you do that, watch the color of your plug. You don't want white or gray, too lean. You want a chocolate brown. Black would be too rich.

The overbore may not increase speed, but should increase torque.

The SB50 has a differently port jug than any of the Sprees.

I agree with the "if you are not gonna go extreme on the mods, better to leave the intake stock."

But increased torque improve acceleration (AKA elapsed time at the drag strip) while increased horsepower only increases top speed if you have the gearing for it.

[Lunytune]

The SB50 has a differently port jug than any of the Sprees.

What is the difference? I would assume the SB50 has improved porting? How is Tazland's 3mm overbore kit ported? Should porting be modified for improvement? I'm new to this and need heavy over the shoulder coaching.

Another issue on Tazland's 3mm overbore kit, the dome piston requires cutting the chamber an extra 3mm. How deep? Mine is still on the shelf but may get installed this winter. I could be porting while I wait if I knew what I was doing.

[Melchior]

I live in Orlando, FL which is a "no-fault" state, which basically translates to "F*ck you".

Everyone races from stoplight-to-stoplight at 60mph and I stay in the far left lane just waiting to get zoomed by street bikes and passed in my own lane. On one recent occasion, someone passed in my lane between me and another car. I was literally inches away from them. Scary stuff. o_0 Apparently turn signals are also out of style.

Lets not forget the close-honkers too...

My spree is my only transportation and there are virtually no backroads what-so-ever. I grew up in Pennsylvania and was used to being able to drive for hours without seeing anyone - impossible now.

I still love riding it though! I've wanted a mini-bike since I was little kid and now I've got the next best thing!

Melchior

[Bear45-70]

The SB50 has a differently port jug than any of the Sprees.

What is the difference? I would assume the SB50 has improved porting? How is Tazland's 3mm overbore kit ported? Should porting be modified for improvement? I'm new to this and need heavy over the shoulder coaching.

Another issue on Tazland's 3mm overbore kit, the dome piston requires cutting the chamber an extra 3mm. How deep? Mine is still on the shelf but may get installed this winter. I could be porting while I wait if I knew what I was doing.

There was a couple of threads that had a chart with the porting specs for a bunch of the different cylinders. See the thread below for a comparison chart.

http://www.hondaspree.net/phpBB3/viewto ... ing#p87063

[Lunytune]

There was a couple of threads that had a chart with the porting specs for a bunch of the different cylinders. See the thread below for a comparison chart.
http://www.hondaspree.net/phpBB3/viewto ... ing#p87063

Without a doubt, the Sb-50 has improved porting. A few questions.
1. The chart measures in degrees BTC? How do I translate that to mm from top? or...
2. I wonder what Tazland porting is? NQ50 or improved SB50? If Spree, the kit will not necessarily help? Increase in displacement but retarded timing?
3. Which ports are exhaust and which are scavenging?
4. My manual says intake is "Reed valve controlled". So no mod change in intake port?

[Bear45-70]

Look here for the crank degrees to piston position conversion. It's aways down the page.

http://www.hondaspree.net/phpBB3/viewto ... =4&t=10478

[Melchior]

Way to hijack the thread there, nucklebusters

Anyhoo, I replaced the original intake tube/filter and now have absolutely no power.

It still idles fine but now has little torque and a much lower top speed.

As i mentioned before i was getting 25-30mph (depending on wind/humidity) without any trouble, but now at full-throttle it just sputters, and occasionally has second-long spurts of it original power. Both idle and mixture screw have very little effect on anything, where before, they had everything to do with its performance.

It also seems to be running very rich, as reflected in my gas guage.

Any ideas?

Thanks,
Melchior

[Spreetard]

how's your air filter look inside your newly re-instated airbox????

sidenote: i likey da' direction o' the hijacked thread 'yall should start a thread on that...

and i like to grind ports, my tazland kit will have big, nasty ports, moving the exhaust port 2mm up and widening 4-6mm. when the snow flies, pictures will follow shortly

[Lunytune]

sidenote: i likey da' direction o' the hijacked thread 'yall should start a thread on that...

Not really. I found lots of answers on the subject in the Advanced Tech Docs. Besides, we need to be fair to Melchior. He thinks we hijacked his thread but really I think we've helped him all we can. Bottom line is you can't monkey with the intake without making other changes. You can't really help a Spree without getting serious on bore and porting. To change the intake and trying to rejet just won't get it.

[Melchior]

The filter is brand-new.

Yes, please start your own topic; it's annoying to get emails about a reply that doesn't concern you...

Melchior