Topic: CB550K0 Build - 450T Tank mods

[RAFster122s]

Not all carbs are identical, over time you may have a deposit in one that doesn't occur in the others. The small passages can be very close. The air feeding may have a twist to it the others do not causing intake backpressure that lessens fuel flow. Might have the head of a screw of the throttle butterfly causing turbulent air and lack of proper atomization.  No telling what could cause it. The jets or needles may not be identcal.

A bit more twist of the adjustment may sort it out.

David

[calj737]

I'd vacuum synch before you start tweaking carbs.

[streak09]

Well, after a brief hiatus I am back tinkering with the 550. Doesn't look too good for having it ride-able for the Barber Festival, but I will keep plugging away. Good stuff is happening so I do not want to rush things (ha, progress is anything but a rush on this build!  ).

My dad purchased a titled bike so we could putts around the back roads legally, but it had a pretty good leak at the cylinder base. I spent a few minutes here and there tearing down the top end and got it back up and going within a couple weeks. This guy is in pretty good condition, its a keeper.



Small projects like the above, redoing my S90 wheels, and that funny thing called life has put the 550 on the back burner for a bit. I did at least start the 550 about every week, just to keep it fresh.


Now enough excuses about why I have been slacking on the 550 and on to some updates...

I found out that I was running all the carbs reaaaalllly lean. So I set them to all about 1.5 turns out, and it seems much better now. After that I synced them up and its running really smooth now. Good throttle response and good idle. I'm not sure if I need to be tweaking the air screws though. I can't distinguish any change when adjusting them.

I splurged and got a Slipstream Cycle rear set kit. Quality seams very good. I will have to tinker with placement as my modified F exhaust causes some clearance issues. The rear sets are designed to mount at the passenger pegs, which I have done for the time being. I think I will end up moving them forward about 3" in the future for a better riding position and better foot angle. I think slightly higher and swept back bars will help as well. My current ones were just in a pile of parts that came with a previous bike. My exhaust is limiting the downward angle of the brake lever, and moving it forward will also give me more clearance to angle it down.






I'm also thinking about painting the linkages and frames black (not the knurled parts). I think it stands out a bit too much for my liking.

After I got them fitted up today I took it for a spin and it was incredible. It felt so good to wind through the gears for the first time. I got a few strange looks in the neighborhood but its all good. I would probably do the same if somebody was riding by with a Simple Green bottle as a fuel tank... It pulled very well, not stutter at all and will go faster than I'm comfortable with right now  . I was very uncomfortable when I started riding, but I settled in after a while and became more comfortable with the riding position. I do think moving the rear sets forward are needed though.

Next order of business is to figure out my tank situation. With help from you guys, I have identified the tank that I picked as a CB450T.





And, as mentioned before, the petcock definitely has clearance issues with the carbs. I do not have the petcock to go with it.



Here is my plan... please chime in with recommendations/harassment

I would like to relocate the petcock somewhere forward of the current location to provide clearance. I've scoped this guy out on 4-1.com


http://4into1.com/honda-fuel-valve-petcock-16-x-1-5mm-16950-292-000-cb350-cb360-cb450/

Now it says its for a 350/360/450, but I think it should work? Now here is the hard part...

The mounting threads are 16 x 1.5. And of course, I can't find a weld-in bung to match. I'm hoping one of our resident machinists could hook me up and make one!?!?! I think something like this is what I will need --> http://www.summitracing.com/parts/sum-220062/overview/ , but in steel so it can be welded in.

Thoughts or directions?

Appreciate those who will make it through the entire post 

[RAFster122s]

If the metal is solid in the bottom of the tank you could braise the fitting into the tank. Hard part is looking like having clean metal as that tank looks a little rough.
David

[calj737]

Cut the existing one out of the bottom of the tank by cutting a surrounding square. Transplant the square with the bung still attached to a new location. Weld in a patch from old hole. Cut new square into new location and weld it up. Done!

Problems like this are about solving the location, not about new machines parts 

[streak09]

Thanks for the input guys.

The tank is a bit rusted, but very solid. No thin spots at all, it has just been painted several times. I kinda like the look actually. Point taken though, the area definitely needs to be clean for welding.

Calj, you bring up a good point as well. In fact, my first intention was to just relocate the existing bung. I teetered on that idea for a bit because of how close it is to the edges of the inner tank. I guess I am going to have to cut it out anyways. I'll give it a shot. I'll bring it by the guy that I would like to weld it and see what he thinks as well.

[RAFster122s]

I've seen several guys try to weld sheet metal and they aren't good at it. They are fine with larger/thicker steel but they blow through the sheet metal. So, finding a good welder who can weld and grind the resulting welds back down and properly clean the welds up after welding is important. Welds just left with no clean up don't fare well is my experience.

[calj737]

I've seen several guys try to weld sheet metal and they aren't good at it. They are fine with larger/thicker steel but they blow through the sheet metal. So, finding a good welder who can weld and grind the resulting welds back down and properly clean the welds up after welding is important. Welds just left with no clean up don't fare well is my experience.

Thin metal is all about heat control. Get your settings right, and you can weld swedish pubic hair together (figuratively speaking of course). Same is true for very thick metal. It takes more heat to weld together. For these tanks, I prefer TIG for this very reason. Tack, move, tack, move, tack, rest. The metal is "thin", but its stronger than you think. Especially the floor plates. But it does take some care to prevent warpage.

It has been my experience, that thickness is not the most difficult part of welding these tanks. Its the potential rust on the inside. Welding a patch into a tank where the interior still has surface rust, or flash rusting, is an impediment to good results. So the interior must be pristine metal for optimum results.

Or, you can install the patch from the interior and use a smaller hole, then weld the hole shut with edges of the patch inside. Less noticeable and perfectly sound result. A small bead of weld looks great too!

[streak09]

The guy I have shouldn't have a problem. He has built a lot of custom fuel tanks. I haven't gotten a chance to bring it by him yet to see what he thinks.

I am planning on de-rusting the tank with naval jelly. I was really happy with the results on the original tank.

[streak09]

Been a while since I have updated! Unfortunately, not a ton going on, but I am (believe it or not) still picking away at this thing.

The goal was to have it presentable for barber, but that has come and gone. Still had a great time at Barber. Beautiful facility and a truly awesome museum. Definitely worth the trip.

I will post a few pictures of our journey this evening.


So for the 550...

Took my tank by the guy that will do the welding and he said he should be able to put a new bung in pretty easily, as long as I get the inside spick and span. So as I type, it is soaking in a Naval Jelly solution. The inside wasn't all that bad, so hopefully this evening it will be cleaned up.

It just so happens that there is a machine shop right next to the guy's shop that will do the welding, and they will turn a bung whatever size is needed so it should work out. A dual outlet petcock is on its way from 4into1.com right now.

I also had to modify the front tank mounts to get the 450T tank to fit. Trimmed a few mm from the rubber pads and metal posts and it slid right on.





I think I will eventually lower the front down 1/2" to 1". It is sitting just a tad to high in the front for my liking.


I don't know if I mentioned this in a previous post, but I did get the carbs synched up, and she really purrs now.

More to follow on the progress on the tank!

[calj737]

Before you go welding in a new bung, I strongly recommend you make dead sure your petcock will clear the carbs. You would not be the first to encounter this conflict after paying for fabrication.

[streak09]

Before you go welding in a new bung, I strongly recommend you make dead sure your petcock will clear the carbs. You would not be the first to encounter this conflict after paying for fabrication.

Will do calj. I am waiting to get the petcock in before I set the location.


A few pictures from the Barber trip.

All loaded down!


We went through Gatlinburg and into the smokies on our way (kinda on our way). We rode the Cade's Cove loop early in the morning with my S90 and C70, that was a blast.


Barber Museum


Sunday morning ride around the grounds


My baby!



Good time, and definitely would recommend the trip!

[streak09]

So, over the hiatus I dropped my tank off to the welder to have a new bung put in. His next door neighbors to his shop turned a custom bung to match the threads of my petcock. He welded it in and leak tested, checked out good.

It lines up perfect and clearance with the carbs is good. He had a tight spot to work with and did a great job. Ill post some pictures this afternoon.

Just some small projects going on while its cold out. Next thing for the bike is to figure out a seat pan.

[RAFster122s]

What year (approximately) is your S90...nice bike by the way!  The tag on the harness beneath the tank gives you a close idea if it is still there and the bike still has its original harness. I have a Nov 1969 build ruby red metallic candy paint on mine with chromed fenders... It isn't on the road as I've not spent any time delving into it...
They are gorgeous bikes and great for running around. The C70 is fun too. I have an 81 in canary yellow as well.

[streak09]

What year (approximately) is your S90...nice bike by the way!

Thanks! I believe it is a '65. Unfortunately the tag on the harness was not there when I bought the bike. It is titled as a '66, but that just means that it was titled in '66 not necessarily manufactured then. From the serial number, the 45 degree head, and the offset carb, I have concluded it to be a '65.

Good luck on your build. They are a bit challenging due to all the nuances and several design changes across the years. I absolutely love it though. This site is a great source when trying to source matching parts --> http://s90partspuzzler.blogspot.com/

The C70 is fun too. I have an 81 in canary yellow as well.

I enjoyed that little bike a lot more than I thought I would. I bought it right before Barber so we all would have a bike to putt around on and didn't think much of it, but it grew on me. Nice to have the e-start. Ended up selling it at Barber right before leaving. It was an '80.

[Godffery]

So...Any updates on this project...?   

[Blakesblakey]

Hello everyone! New owner, started a new thread:

http://forums.sohc4.net/index.php/topic,182001.0.html