1988 SB50 sputters high speed

Bear45-70 · Post by **Bear45-70** » Mon Sep 20, 2010 12:18 pm

smanke wrote:What do you mean fix the post?

I mean I made it so you can see the picks without opening another tab or window.

You can do it too by using the bottom link under you pics that have [img]before%20and[/img] after the link.

smanke · Post by **smanke** » Mon Sep 20, 2010 12:45 pm

Thank you for doing that. So do you see anything that looks weird? Do you know of anyone in my area that may be able to help?

Wheelman-111 · Post by **Wheelman-111** » Mon Sep 20, 2010 12:50 pm

Greetings:

Did you slide the bystarter cover off to take the pic or are you running it like that? The cover helps to keep the unit warm and thus running in the "non-enriched" position. If it's cool outside, the bystarter might try to retract at speed (?). I know it's lame but worth mentioning.

More importantly, check the o-ring around the bystarter, the carb insulator, and any other sources for vac leaks. The insulator installs with its "dog ears" pointing down, and such that there's an o-ring on either side, as opposed to two o-rings on the same side. A good seal here is critical.

smanke · Post by **smanke** » Mon Sep 20, 2010 4:36 pm

I took the cover off the bystarter just for the pic. I have checked the carb insulator and all the other o rings and gaskets for the intake and they are ok. The o ring for the bystarter is ok. I did a test just now my dad suggested. I ran it at a constant 25 and 30 mph and it ran fine. So it only does it at WOT. So I hope with this new info someone out there might have the answer. Scooter gods help save the day!

smanke · Post by **smanke** » Tue Mar 29, 2011 12:09 am

So spring has arrived and it's back to working on the scooter. With the rise in gas prices it's more imperative that I get it running correctly. I took it for a spin a couple days ago and still has the same problem. I took the carb off for the millionth time and soaked it in Berryman's cleaner for a week. I put it back together and still the same d*** problem. Is there anyone that has any insight or theories? I have reached my last straw with this scooter.

Bear45-70 · Post by **Bear45-70** » Tue Mar 29, 2011 12:12 am

Did you get some spray cleaner and spray thru all the passages? If not soaking may well not cure your issues.

smanke · Post by **smanke** » Tue Mar 29, 2011 12:19 am

I have sprayed through all the passage ways numerous times with carb cleaner. It still doesn't seem to change a thing. I still believe it's a fuel issue. If I could find another carb to try that would be great. Has anyone else had this problem? Would anyone like to take on this project?

JJ Joseph · Post by **JJ Joseph** » Wed Apr 06, 2011 1:40 am

smanke wrote:I have sprayed through all the passage ways numerous times with carb cleaner. It still doesn't seem to change a thing. I still believe it's a fuel issue. If I could find another carb to try that would be great. Has anyone else had this problem? Would anyone like to take on this project?

That reminds me of just about every 2-stroke I've ever had. There's a lot of black-magic and prayer involved in tuning a 2-stroke. You're right, it sounds like a mixture problem. But it could be either too rich or too lean. Smart 2-stroke tuners have a range of jets to try, and they just start working through them until they've tried all combinations. Start with three main jets, one above and below what's in the carb now. If it's a 65 jet, get a 62 and a 68. The needle has 5 settings, so the total is 3x5=15 setttings. I keep a little notebook and record every setting until I get it narrowed down to a range of workable combinations. Never mind checking the color of the spark-plug (it takes too long). Just be patient and make lots of notes. It's REALLY frustrating if you're used to 4-strokes & computer diagnostics! Just to be on the safe side, you should also check the reed-valve. A weak or cracked reed-valve will cause similar problems, and reed-valves have a nasty, short life.

Bear45-70 · Post by **Bear45-70** » Wed Apr 06, 2011 1:50 am

JJ Joseph wrote:
smanke wrote:I have sprayed through all the passage ways numerous times with carb cleaner. It still doesn't seem to change a thing. I still believe it's a fuel issue. If I could find another carb to try that would be great. Has anyone else had this problem? Would anyone like to take on this project?
That reminds me of just about every 2-stroke I've ever had. There's a lot of black-magic and prayer involved in tuning a 2-stroke. You're right, it sounds like a mixture problem. But it could be either too rich or too lean. Smart 2-stroke tuners have a range of jets to try, and they just start working through them until they've tried all combinations. Start with three main jets, one above and below what's in the carb now. If it's a 65 jet, get a 62 and a 68. The needle has 5 settings, so the total is 3x5=15 setttings. I keep a little notebook and record every setting until I get it narrowed down to a range of workable combinations. Never mind checking the color of the spark-plug (it takes too long). Just be patient and make lots of notes. It's REALLY frustrating if you're used to 4-strokes & computer diagnostics! Just to be on the safe side, you should also check the reed-valve. A weak or cracked reed-valve will cause similar problems, and reed-valves have a nasty, short life.

Doing a plug chop and reading the plug before making any change and again after any change would be a * of a lot quicker and a lot more accurate a tuning guide that doing it the hard way and long way you have described.

Post by **noiseguy** » Wed Apr 06, 2011 10:07 am

Jesus C. This is why we need the pictures.

Symptoms are classic for soft-seize.

You are running your bike without all the cooling tin in place? Where's the plastic cover for the cylinder? I don't see it on the bike. If it's missing it can cause overheating. Am nearly certain this is the problem.

Other things:

Assume you've checked and replaced the filter element. They rot after a few years.
Would suggest you replace fuel/vac lines with clear ones so you can see what's going on, if this continues to be a point of confusion.
Did you remove and clean the emulsion tube in the carb? Often overlooked.

smanke · Post by **smanke** » Wed Apr 06, 2011 12:09 pm

I got this scooter from my dad's girlfriend. She was going to throw it out with the garbage. It had been sitting in a garage for the past 15 years. I could tell that someone was working on it to get it running before I got it and they didn't know what they were doing. There was no cover or anything when I got it over the cylinder. Is it supposed to be metal or plastic? Any idea if I can get a replacement? I have had the carb apart many times. Which exactly is the emulsion tube? I checked the reed valves per the service manual and they were ok.

smanke · Post by **smanke** » Wed Apr 06, 2011 12:12 pm

I have checked the condition of the fuel and vacuum lines and they are ok. I have clear fuel line running from the tank to the carb.

Post by **noiseguy** » Wed Apr 06, 2011 3:40 pm

The part is black plastic and forms a 4-sided box. You will need to either locate the part in the garage where it was being worked on, or obtain a replacement. I'm not sure if the Spree part will fit; it would be easier to find. Otherwise you can buy one new from Honda (if available) or make one from tin (if you know what it's supposed to look like.)

Here's one from a Spree, with head and cylinder:

http://cgi.ebay.com/ebaymotors/1986-Hon ... leQ5fParts

D/l the service manual or look at the microfiche to see how it goes together.

Emulsion tube is what the needle valve goes into. It's under the main jet and, after removing the main jet, can be pushed out from the top with a dowel/pencil/something softer than steel. Many ppl forget to clean this part.

Clear lines tell you what's going on inside. Swapping out the stock lines is one of the first things I do on any of my bikes. Both vacuum and fuel.

Bear45-70 · Post by **Bear45-70** » Wed Apr 06, 2011 4:04 pm

smanke wrote:I got this scooter from my dad's girlfriend. She was going to throw it out with the garbage. It had been sitting in a garage for the past 15 years. I could tell that someone was working on it to get it running before I got it and they didn't know what they were doing. There was no cover or anything when I got it over the cylinder. Is it supposed to be metal or plastic? Any idea if I can get a replacement? I have had the carb apart many times. Which exactly is the emulsion tube? I checked the reed valves per the service manual and they were ok.

Look here for pictures of carb parts.

http://hondaspree.net/wiki/index.php5?t ... ture_Guide

smanke · Post by **smanke** » Wed Apr 06, 2011 6:58 pm

My dad is checking tonight if they still have the shroud over the cylinder. I have the rubber piece that connects to the shroud that goes around the end of the carb. Don't know why I didn't realize earlier that something big was missing. I hope that this will solve my problem. I'm pretty sure that I cleaned the emulsion tube but I will double check. I will let you know how things go. With gas prices going sky high I will be glad to drive this little gem around. It only has 200 miles! I really do appreciate all the help.

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1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed

Re: 1988 SB50 sputters high speed