Express SR Bystarter

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Express SR Bystarter

Postby Sean L. » Sat Jul 26, 2008 2:00 am

In my endeavour to repair the bike, I've had to make a few mods to compensate for missing/crumbled parts. One of the parts which had disintegrated was the airbox. I've come up with a simple filtration solution for the moment, but I haven't dealt with the bystarter yet. Unlike later Hondas, the Express SR uses some form of a foam filter in a rubber housing which plugs into the side of the airbox. As my bike no longer has an airbox, I believe I'll need to replace this solution with something enclosed in order for the auto-choke to work right. Has anyone else had to deal with this, or does anyone have a spare usable Express SR airbox they'd be willing to sell?

I suspect this part is important, as the bike runs decently when cold and can be ridden about at 10 MPH until the engine is warm enough (~1 min). Once it's warm, the bike will bog when the drive pulley takes up enough. This might be due to an improperly sized belt taking up too early or the low compression, but the fact that it can be ridden until warmed up makes me thing that the bogging is related to the automatic choke system.
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Current Scoot:

'81 Honda Express SR

Mopeds Previously Owned:

'77 Puch Maxi
'78 Puch Maxi
'85 Puch Maxi
'76 Sparta Buddy
'77 Sparta Buddy
'81 Murray
'78 Motobecane
'77 Garelli Rally Sport
'85 Kamasura
Sean L.
Net Rider
 
Posts: 64
Joined: Sun Jul 20, 2008 7:12 pm
Location: Tucson, AZ

Bystarter Solution

Postby Sean L. » Sun Jul 27, 2008 10:26 pm

Ingredients:

- 1.5" of 5/8" ID fuel hose
- 1 cylindrical shaving of filter foam from a generic Briggs & Stratton filter (bought mine at ACE Hardware), 1" long and shaved to fit into a 5/8" ID fuel hose
- 1 universal vacuum adapter from AutoZone (Vacu-Tite! #47309)
- 2 Zip-Ties or Zebra clamps

Procedure:

1. Cut the narrow center section out of the vacuum fitting, leaving only the ends.

2. Clip the ends to the second barb fitting in, unless your vehicle has larger/smaller hoses. Measure your bystarter connection hoses and trim accordingly.

3. Take a paperclip or a piece of small, solid-core wire and make a little hook on the end. Use the hook to draw the foam tube into the length of fuel line. Pull the foam instead of pushing it in order to prevent bunching and increased airflow restriction. Center the foam in the line to leave room to install the vacuum fittings.

4. Gently press a vacuum fitting into each end of the fuel line, barb ends facing out. Use the Zip-Ties or Zebra clamps to secure the 5/8" fuel hose to the vacuum barbs.

5. Connect the #3 line to one end of the filter assembly and the #4 hose to the other. Secure using the Honda wire clamps or another small-gage clamp or Zip-Ties.

6. Install and test-ride.

I found this device did affect the warm up time of the bike, making it noticably shorter. I don't know what the original cycle of the factory bystarter is, but this did decrease the warm-up time on my NX50M from over a minute to 30 seconds or less. Best part is, I have no wayward hoses flailing about now!
You do not have the required permissions to view the files attached to this post.
Current Scoot:

'81 Honda Express SR

Mopeds Previously Owned:

'77 Puch Maxi
'78 Puch Maxi
'85 Puch Maxi
'76 Sparta Buddy
'77 Sparta Buddy
'81 Murray
'78 Motobecane
'77 Garelli Rally Sport
'85 Kamasura
Sean L.
Net Rider
 
Posts: 64
Joined: Sun Jul 20, 2008 7:12 pm
Location: Tucson, AZ

Bystarter Solution Installed

Postby Sean L. » Sun Jul 27, 2008 10:33 pm

Here's the improv bystarter filter as installed on the bike. The #4 line exits the carburetor at the black plastic fitting just ahead of the throttle valve and plugs into the fore end of the filter. The #3 hose plugs into the aft end of the filter and loops around to head up to the automatic choke assembly. I had the Briggs filter handy , as I'd just made a new filter for a gas leafblower and had extra foam. The Zip-Ties were a prepaid item too, but I'd bet that this thing could be fabricated for about $7 if you shop smart.
You do not have the required permissions to view the files attached to this post.
Current Scoot:

'81 Honda Express SR

Mopeds Previously Owned:

'77 Puch Maxi
'78 Puch Maxi
'85 Puch Maxi
'76 Sparta Buddy
'77 Sparta Buddy
'81 Murray
'78 Motobecane
'77 Garelli Rally Sport
'85 Kamasura
Sean L.
Net Rider
 
Posts: 64
Joined: Sun Jul 20, 2008 7:12 pm
Location: Tucson, AZ

re: Express SR Bystarter

Postby silverfox » Mon Jul 28, 2008 11:48 am

What does you plug look like? An aftermarket filter is usually quite a bit less restrictive than the stock one. Meaning that at open throttle you are running very lean.

Can't help you with that auto choke deal.
silverfox
Net Rider
 
Posts: 619
Joined: Tue Mar 22, 2005 1:15 pm
Location: San Francisco Peninsula

re: Express SR Bystarter

Postby Sean L. » Mon Jul 28, 2008 3:10 pm

Plug was a black and slightly oil-fouled when I got the bike. Haven't been able to run it long enough to get a good reading on the current setup.

I could cut a plug out of a generic Briggs filter and fit it in the cone if it needs extra filtration. I'd have preferred to use the stock setup, but the airbox and rear fender had crumbled from UV damage (Arizona sun is murder on plastics and upholstery!) and there wasn't much in the way of usable thiings left, save for the bystarter housing and the intake hose between the carb and the airbox.

At least the hose lets me angle the intake away from the back tire; I can imagine how long the motor would last with road grit being thrown directly into the carb throat!
Current Scoot:

'81 Honda Express SR

Mopeds Previously Owned:

'77 Puch Maxi
'78 Puch Maxi
'85 Puch Maxi
'76 Sparta Buddy
'77 Sparta Buddy
'81 Murray
'78 Motobecane
'77 Garelli Rally Sport
'85 Kamasura
Sean L.
Net Rider
 
Posts: 64
Joined: Sun Jul 20, 2008 7:12 pm
Location: Tucson, AZ

re: Express SR Bystarter

Postby Sean L. » Tue Oct 21, 2008 10:02 pm

Update:

Pulled the covers this weekend to get the VIN's for the MVD and found that the bystarter had worked loose and wasn't touching the head. Pulled the unit off and cleaned it out. Had to fabricate a replacement sealing washer between the bimetal spring housing and the valve assembly; sanding fiber washers is tricky! Reassembled the bystarter and polished the mating surfaces for the bystarter and the head. Gonna reinstall now with a bit of PC heatsink compound, Here's to hoping for improved functionality!
Current Scoot:

'81 Honda Express SR

Mopeds Previously Owned:

'77 Puch Maxi
'78 Puch Maxi
'85 Puch Maxi
'76 Sparta Buddy
'77 Sparta Buddy
'81 Murray
'78 Motobecane
'77 Garelli Rally Sport
'85 Kamasura
Sean L.
Net Rider
 
Posts: 64
Joined: Sun Jul 20, 2008 7:12 pm
Location: Tucson, AZ

re: Express SR Bystarter

Postby Sean L. » Wed Oct 22, 2008 11:40 pm

It works! Doesn't warm up as quickly as my CH80, but I'm a lot happier with it. Now all I need to do is finish goofing around with the MVD and prep it to run the Tucson Scooter Rally...

http://www.tucsonscooterrally.com/
Current Scoot:

'81 Honda Express SR

Mopeds Previously Owned:

'77 Puch Maxi
'78 Puch Maxi
'85 Puch Maxi
'76 Sparta Buddy
'77 Sparta Buddy
'81 Murray
'78 Motobecane
'77 Garelli Rally Sport
'85 Kamasura
Sean L.
Net Rider
 
Posts: 64
Joined: Sun Jul 20, 2008 7:12 pm
Location: Tucson, AZ


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