Topic: Marissa's 1972 CB500

[DaveBarbier]

Yeah I’d say go with points. The Dyna S is nice but it’s more expensive and points are super reliable. You won’t get any reduction in horsepower at all. It’ll be as smooth and happy as any electronic ignition.

I haven’t used Hondaman’s box but 100% of people here recommend it. Never heard anything bad about it.

[Marissa]

Alright, new OEM points plate assembly ordered from DSS.

Progress has been little to none. I've had no time thanks to work and school. Quitting my job to focus on finishing up my final year in school and doing a little part time gig to keep some money coming in. Hopefully will have more time for the bike as well.

Started using the Astro pneumatic threadserts. Satisfying stuff. I will find more opportunities to use it I'm sure.



Definitely something not right with these carbs. Bike has been sitting for a month now and there's wet gas seen by the butterfly. These floats will be the death of me.



Since it's already so cold out, I decided to make a blueprint for the electronics tray. I used a free program called Sketchup. I now have a fully scaled template for when I'm ready to assemble.









That's all for now.

[DaveBarbier]

I have no idea what’s going on with your carbs. They were by no means pristine examples of keihin carbs but they were clean and seemed like they’d function properly.

As for the points plate and rivet threads, awesome! Will you be using this CAD thing as just a template to make one from metal or 3D printing anything?

[Marissa]

Unfortunately I don't know anyone that can 3D print that large, so I'll be making it out of 5052 aluminum.

[Marissa]

Got the points system in today. After an hour of trying to set the timing, I figured out I set the points cam in 180 off. Whoops. Fixed that and finally setting the ignition timing was a breeze.

Now I can 100% confirm my issues are purely carburetor. These carbs are now rev hanging too like my other set was. Frustrating and tiring.

I guess I will be rebuilding these over the course of the next few weeks.

Does anyone on here rebuild these? I'd consider shipping these to someone who truly knows these if its a solid price vs. dealing with whatever local Harley shops would do.

Here's a vid:

[jgger]

I'm going to go out on a limb here and that sounds like a cable or linkage issue to me. Trying to not sound insulting here, but are you positive that everything is closing down when the throttle is closed? But once again I could be full of crap, and I didn't stay at a Holiday Inn last night either. Haha.

[HondaMan]

This is a common symptom when a couple of things are present.
One is: too-soft springs in the spark advancer (this will make it REAL sensitive to anything else that is wrong).
Another is: the tiny O-rings on the mainjets are too old and have turned to plastic now (thanks in part to ethanol), so they leak fuel past them, unmetered fuel.

One thing that may get you running long enough to figure out if the carbs are the culprit or the spark advancer is: retard the spark timing to almost "T" on both sets of points, by turning the whole points plate CCW a little. Then when it starts it will be retarded in timing, making it less sensitive to the spark advancer portion of this issue. If it still wants to jump up and idle at 3500 RPM (like it sounds) then the mainjet O-rings are likely at fault. Given your dark sparkplugs (or were those from the other carbs?), this seems likely.

The biggest issue we are seeing right now in rebuild kits for these carbs is: too-big O-rings in the non-Honda kits. This prevents the jets and the float valves from being assembled properly, even to the point of breaking parts. They are supposed to be 1.2mm in cross-section, but the kits supply 1.5 or 1.6mm instead, causing the trouble. This is the #1 reason why it seems so hard to rebuild the CB500/550/400fcarbs these days!

The carb 'rebuild' consists of (besides cleaning) replacing the O-rings on the mainjets, float bowl drain screws, and the fuel feed tubes, and sometimes the float bowl O-ring that seals it all up. It's pretty simple, especially for someone with fingers as nimble as yours! It's just hard to get the right O-rings. I have tried before (and may try again) to have a local seal shop import a bag full of these tiny ones: if I can get them, I'll let everyone here know about it.

[Cb750 Racer]

Got the points system in today. After an hour of trying to set the timing, I figured out I set the points cam in 180 off. Whoops. Fixed that and finally setting the ignition timing was a breeze.

Now I can 100% confirm my issues are purely carburetor. These carbs are now rev hanging too like my other set was. Frustrating and tiring.

I guess I will be rebuilding these over the course of the next few weeks.

Does anyone on here rebuild these? I'd consider shipping these to someone who truly knows these if its a solid price vs. dealing with whatever local Harley shops would do.

Here's a vid:

How far are you from CCSU? I could stop by and take a look after class one day if your up for it. The bikes been at 95% for too long IMO

[jgger]

Honda man have you tried these guys?
https://www.theoringstore.com/

[knosalaa]

Just a quick question, and btw after 10 pages google showed no answer, can you charge lead acid standard motorcycle battery with agm charger? I know you can’t use standard charger on agm batteries but my question is the other way around. I have a bmw agm charger/maintainer we use to charge when in vacations.

[RAFster122s]

This is a common symptom when a couple of things are present.
One is: too-soft springs in the spark advancer (this will make it REAL sensitive to anything else that is wrong).
Another is: the tiny O-rings on the mainjets are too old and have turned to plastic now (thanks in part to ethanol), so they leak fuel past them, unmetered fuel.

One thing that may get you running long enough to figure out if the carbs are the culprit or the spark advancer is: retard the spark timing to almost "T" on both sets of points, by turning the whole points plate CCW a little. Then when it starts it will be retarded in timing, making it less sensitive to the spark advancer portion of this issue. If it still wants to jump up and idle at 3500 RPM (like it sounds) then the mainjet O-rings are likely at fault. Given your dark sparkplugs (or were those from the other carbs?), this seems likely.

The biggest issue we are seeing right now in rebuild kits for these carbs is: too-big O-rings in the non-Honda kits. This prevents the jets and the float valves from being assembled properly, even to the point of breaking parts. They are supposed to be 1.2mm in cross-section, but the kits supply 1.5 or 1.6mm instead, causing the trouble. This is the #1 reason why it seems so hard to rebuild the CB500/550/400fcarbs these days!

The carb 'rebuild' consists of (besides cleaning) replacing the O-rings on the mainjets, float bowl drain screws, and the fuel feed tubes, and sometimes the float bowl O-ring that seals it all up. It's pretty simple, especially for someone with fingers as nimble as yours! It's just hard to get the right O-rings. I have tried before (and may try again) to have a local seal shop import a bag full of these tiny ones: if I can get them, I'll let everyone here know about it.

Like “Donkey” from Shrek says, “Oh, pick me!  Pick me!” With regard to having my hand up on wanting a set or two of the O-rings for the 550. If stored in cooler conditions and not where UV light are the Orings are showing bad wear...then maybe the Silverstone section can enlighten me on the

[RAFster122s]

Marissa, how are you?  How is life treating you and your family and friends?  Any work on the bike since last report?
I hope you and family and friends are staying healthy.

[Marissa]

Marissa, how are you?  How is life treating you and your family and friends?  Any work on the bike since last report?
I hope you and family and friends are staying healthy.

Hi RAF!

My bike is now finally ridable. You may have seen DaveBarbier's post with setting float height on CB500 carbs with a whiskey glass, that was actually for my bike. Dave dialed in float height, found my valve lash for virtually all valves got loose, and got some seat time in and later adjusted needle settings for me! Wouldn't be here without him. Super happy.

The bike is still very much a project. Currently I still need to remake my sub harness, extend the harness for the "idiot lights", add a relay/transistor for the LED turn signals, adjust my rear brake pedal, etc. But right now I'm having some issues with the rear end, and the threaded bearing retainer. Also w/my 2nd Shorai battery 

Attaching some pictures for now, my spacebar key is broken and I have a Mac so I have to bring it to Apple to fix. Until then won't have a lot of story to tell!

[RAFster122s]

What's up with your threaded bearing retainer? Drill out the stakes areas before starting to get it removed I hope.  DSS, David Silers Spares carries a bearing retainer removal tool but the one I bought from them I had to return as it could only fit three of the four circular staked holes instead of four as it was supposed to.  I made them aware of the problem and they accepted the return no problem and took the product down for a while. Presumably to get their supplier to fix the problem. It worked very well to remove the bearing retainer even with only three of the four engaged.  The bolt circle/radius the pins for remove the bearing retainer was fitted to was a mm or so off, enough to cause the problem. They checked it with an aftermarket retainer, same problem, and a original equipment bearing retainer as well. Just to rule out the aftermarket parts being the issue.

Glad Dave lent you a hand and you have been enjoying the bike.
Hope you can continue to do so this summer and nothing major takes it off the road on you. Two wheel therapy is far better than a shrink's fees.

[Scott S]

 And if you're talking about the rear wheel retainer, it's reverse thread. Make sure you're going in the right direction! It's a very fine thread too, so be careful when you go to thread it back in.

[MauiK3]

Great to see you are still at it!

[Marks78]

Great news! Glad to hear you didn't give up on it. Now that it's rideable at least you can have fun in between down times. 

[MauiK3]

Marissa
Is there anything new to report on your project?

[newday777]

I see it's been 3 years since any update. Are you still with us???

[Stev-o]

I see it's been 3 years since any update. Are you still with us???

She hasnt been on here in over two years

[newday777]

I see it's been 3 years since any update. Are you still with us???

She hasnt been on here in over two years

I saw that but hopefully she gets notifications still and will reply back. Hopefully she is OK.

[jgger]

She was a determined gal, I enjoyed reading her posts. I think she had half the forum cheering her on.

I too would like to see an update.

[70CB750]

Given her age I think she has more important things to worry about. 

[Stev-o]

Interesting article about her....

http://crescentmagazine.org/proving-herself

[jgger]

Interesting. Good on her in her endeavors, but she could check in at least to say hi.