[woody1981]

I'm continuing this topic here.

I now have all the parts I need for my swap. The smallest jets I could get my hands on were some 130s... so we're gonna try those first. If they don't work. I will solder and re-drill the original 145s to a smaller size.

I am planning to finish rebuilding the carbs this weekend and hopefully install them for a trial run.

One question. I am going to use the manifolds off the 450... they aren't terrible... but they could be softer. Any tips on breathing new life into them? Boiling?

- Woody

 

[tbpmusic]

Woody -

There was a lengthy thread about this on the SOHC Fours Forum recently.
One method that seemed to work for a lot of folks was to boil them in a wintergreen oil solution.
Do a Search over there for the formula.

bill

 

[woody1981]

Looks like a 30/70 Wintergreen oil/xylene solution... soak for 12-24hrs and you're golden. I'll try that this weekend too.

- Woody

 

[JeyLux]

i usually just use my heat gun while installing and hope for the best,

this wintergreen solution is interesting, where does one buy something like that?

 

[tbpmusic]

i usually just use my heat gun while installing and hope for the best,

this wintergreen solution is interesting, where does one buy something like that?

Drug store.

bill

 

[jmartin419]

Woody -

There was a lengthy thread about this on the SOHC Fours Forum recently.
One method that seemed to work for a lot of folks was to boil them in a wintergreen oil solution.
Do a Search over there for the formula.

bill

Very interesting...I've never heard of that before. Definitely have to keep it in mind.

 

[woody1981]

Well I'm trying the Wintergreen Oil / Xylene mix right now. We'll see how it worked out tomorrow.

I was able to get the wintergreen oil at a local Walgreen's Pharmacy... first place I stopped to try and get it. I just asked the pharmacist at the counter and she got a 2oz bottle from back where they keep all the good drugs. It cost me about $7 for 2oz.

I'll post the results tomorrow.

I also finished up the carbs. They are ready to be mounted on the bike and see how it goes. So as soon as I have nice soft manifolds we'll get to tuning. The carbs now have 130 main jets and still the 38's for the other jet. Fingers crossed.

- Woody

 

[woody1981]

Wow! My manifolds weren't that hard... Not like unusable hard or anything. But now they are crazy good. I would recommend the wintergreen oil xymol mixture to everyone. The the first manifold is super-soft after just 12 hours of soaking. I put the second one in and it will be good tonight. They even smell good when they're done. I'd tell everyone to use this method to soften rubber... It's amazing.

- Woody

 

[tbpmusic]

So woody - tell us the exact formulation and procedure that you used.

bill

 

[woody1981]

Glass mason jar. 2oz Wintergreen oil. 7oz Xylene. Pour both in the jar... drop in rubber part... wait 12hrs... remove and be happy about how well it worked.

The 9oz mixture is only enough to cover one manifold at a time... if you want to do two at a time you would need to double the mixtures quantities.

Good luck.

- Jonathan "Woody" Wood

So woody - tell us the exact formulation and procedure that you used.

bill

 

[JeyLux]

that's cool

normally everything i do smells horrible and lasts for days.


it'd be nice to have a project that smelled decent... ha

 

[CBGP]

Anxious to hear how it runs and glad to know about the rubber rejuvination. I just picked up 3 pairs and one single CB450 carb... :shock:

 

[woody1981]

Awww crap.

Well, this project might have just come to a screeching hault. Maybe even the end.

Last night I took my newly softened carb manifolds and drilled out the mounting holes slightly to allow them to be mounted on the 350 head... worked no great. Went to install the carbs and boom, problem. The 450 Manifolds don't have any angle to them... they just point straight back... not outward at all like the 350 manifolds. The pivot shaft of the choke butterfly that protrudes from the side of the carb hits the spine tube of the frame and stops the carb from fully seating in the boot. It goes in far enough to hold without a clamp, but not all the way. And the drag from the pivot on the spine makes the choke lever not operate smoothly... that and the velocity stacks were resting against the battery box. As much as the twin vibes I don't really want ANY hard parts touching the frame. The only solution I could see is if there were other manifolds that cant outward like the stock 350 boots and were big enough for the larger carbs... I briefly tried to fit the 450 carbs in the 350 boots, but it was pretty obvious that was a stupid idea.

How big are CB360 carbs? Do the boots cant outward? Boots off an XS650 maybe? Suggestions?

In the mean time I went ahead and shimmed the needles in my 350 carbs and re-installed them. I also adjusted the A/F screw to richen the mixture. It starts and idles perfect... but I haven't ridden it yet to see if I am okay or if I am going to go lean at WOT.

I might just keep my fresh and clean 450 carbs, put the 145 jets back in and use them on my 450 when it gets back together. Or I might have a nice set of rebuilt carbs for sale soon. I was planning to put mikunis on the 450... but maybe I'll just save the cash.

Who knows. Kinda disappointing after all the hard work and $$ I've spent on rebuild kits, jets, etc...

At least I have learned A LOT in this whole process. I just want to get this bike to the point that I am happy with it for the time being and I can concentrate on my 350F and 450 builds.

- Woody

 

[tbpmusic]

Woody -

I recall that when Steve and I were experimenting with 175 and 200 carb/air cleaner setups, we kept running into the frame interference problem.
Steve can give his details, but I remember that he made new air cleaner-to-intake boots out of radiator hose, which can be found with all sorts of diameters and angles.
Might not the same idea be applied here???

I know for sure that CB400/450 twin (late 70's) manifold rubbers will not fit on 450 carbs - not sure about 360 carbs, but they're likely the same as 350.

And please be sure to at least stick a chunk of foam into velocity stacks - makes my toes curl up just to think of the problems they could cause on 450 carbs, which have to be kept scrupulously clean.

Incidentally, this is not worthy of a Homer Award, sorry. You gave it a helluva try and answered a lot of questions some of us had. Nothing embarrasing here, just disappointment for you.

On the other hand, I guess you could have tried the fitment first>>
Hmmmm.....

bill

 

[66Sprint]

Woody, I had a similar problem when putting a 360 engine into an SL 350 frame.... Ultimately, I used the infamous ball peen/ hammer dent method to achieve clearance for the carbs and exhaust pipe..... If properly done it actually "stiffens" the frame and does not have to be "ugly"...... You may be able to get carb clearance on yours this way...... Here's the one I did.....

You CAN have a beveled "wedge" plate made up to angle mount the carbs as well, but it might be expensive at a machine shop....I made some years ago with hand tools, but it took forever.....Steve

 

[woody1981]

Well I got home from work and fired up the ride.

Let it warm up for almost 5min. Idle is great. Idles about 2000RPM with full choke. Opened the choke to full open idle settled down to 1200RPM... nice. Hopped on an took off.

No backfiring or popping on deceleration... sweet. Just cruising around its great. I didn't have a highway to test on this short ride but even at short bursts of WOT it seems great. There might have been just a touch of hesitation when I went WOT, but I think its more from opening the throttle to fast than from needing larger main jets.

Overall its running so well I am probably going to hold off on the 450 carbs... sigh. I might tackle it again in the dead of winter when there is snow on the ground. The idea of the angled plates is a good idea... I know a good machine shop and I think that would be my best option.

I don't think the dream is dead... just on hold.

One other problem I noticed is that I need a 450 throttle cable to use the 450 carbs cause the 350 cable holds the butterflys open, even with the adjustment screws run all the way in.

I've moved on to my next project on it... new headlight and bracket. Custom.

This post will be revived again soon.

- Woody

 

[arkieoscar]

My experience with this is close to 40 years old but I ran a set of 450 (CV) carbs on my Triumph flat track bike. The idea was that the damped, rising slide would let the power some on more controllably than the Amal GPs that I was running. The idea behind constant velocity carbs is that the fuel/air mixture is supposed to stay the same throughout the range of thottle opening. I didn't get much chance to experiment with them as they didn't flow enough air at full throttle to make the horsepower that I needed but the mixture wasn't the problem and I went back to the PITA Amals.