Topic: Non-running CB550 - Danger signs?

[ekpent]

If the slides are stuck try a heat gun on the carbs first to try and break the varnish loose before removing or have one handy after they are off. If like the earlier 550 carbs have some new o-rings ready for the jets,float seat etc. as they should probably be replaced and knock out the emulsion tubes and get them clean also. Fun stuff !

[bryanj]

You can get new pattern press in pilots from Sirius in Canada now and somebody of the forum was producing small batches of the inlet to carb rubbers as and when.
Make your job easier and purchase 4 new carb to head rubbers from Honda (Dave Silver sells them) in the grand scheme/cost they aint that bad.
To get the pilots out you needto remove floats, mains etc to get space the grip firmly but not too tight with vice grips and pull/twist at the same time. Replace with a sharpe tap from a SMALL hammer.
Good luck, last time i had one of those i had to clean them 3 times in 3 weeks then it was sat for 6 weeks and i had to do it again!!

[Deltarider]

That's a very nice looking K4 (stepped seat ). Like many already said, you can expect (partially) blocked slow jets. When about to start, I'd use a fuel system cleaner in a pretty high dose. In Europe we have Redex, Tunap, Forté, etc, all probably similar to your Seafoam. Another danger is the O-rings. If the bike has sat for a long period of time, I'd use an oil that helps swelling up the rubber parts like Castrol High Mileage and hope the best of it. When starting, warm it up gently which is a bit difficult as the K3/4s tend to rev to over 3000 rpm rightaway. If you pour in synthetic oil and rev it after a cold start, you can almost wait for it...

[toomanybikes]

Lots of good info there, Thanks all. She is definitely a clean machine as I've been polishing before any mechanical or fuel work. I'll post more complete pics in a diff show-off thread.

I'll definitely try the heat gun to loosen the slides, after taking the tank off to avoid paint damage.

The PO seemed to be meticulous, so perhaps he drained the carbs before any sitting. I'll try a start or two without fully pulling the carbs, maybe I'll get lucky. I've cleaned many carbs before, so the hardest part is likely to be getting them off without damaging the rubber connectors.

BG44k is my preferred chemical fuel/carb cleaner, but it won't clear fully clogged passages.

Stay tuned.

[toomanybikes]

That's a very nice looking K4 (stepped seat ). Like many already said, you can expect (partially) blocked slow jets. When about to start, I'd use a fuel system cleaner in a pretty high dose. In Europe we have Redex, Tunap, Forté, etc, all probably similar to your Seafoam. Another danger is the O-rings. If the bike has sat for a long period of time, I'd use an oil that helps swelling up the rubber parts like Castrol High Mileage and hope the best of it. When starting, warm it up gently which is a bit difficult as the K3/4s tend to rev to over 3000 rpm rightaway. If you pour in synthetic oil and rev it after a cold start, you can almost wait for it...

DeltaRider, I thought the Castrol high mileage wasn't good for wet clutches. Are you proposing a relatively short usage of it to just swell the orings, then replace with something more normal, like Rotella T4 15w-40. No intention to start an oil war. I know what I like. 

[Deltarider]

My CB500 has had Castrol's High Mileage 15W-40 for years now. It's a strong oil that also keeps the rubber parts supple. I did not even have to replace the shifter rod's seal which is notorious for leaking. No problem with the clutch whatsoever. Now you mention it, I can't recall I've ever heard of any CB500 or CB550 that had clutch problems due to oil.

[Erny]

What exact Castrol oil it is? For cars?
I need to select one for my CB550K1, 15k miles on tacho.
But looking on web quickly, it seems that castrol is syntetic? I want to keep only mineral.

[Deltarider]

What exact Castrol oil it is? For cars?

To me that's irrelevant. Back then, the oil that every dealer in Holland used to service Japanese (and not only Japanese) bikes was Castrol's GTX2, not a specific 'motorcycle oil' either. Some seem to think that if you select an oil that does not say JASO-MA on the package, you automatically will face trouble with the clutch*. This is not the case. Some wet clutches are sensitive for this, some are not. The only bike I ever experienced a minor clutch slippage, was a Yamaha XS650. I adviced the owner to change the oil for one used in Yamaha workshops and he later informed me that after the oilchange the slippage had gone. What I look for in an oil above all, is its capacity to preserve the rubbers and the valve stem seals in particular. Every year my bike is hibernating for some five months. The only time I had O-rings (oilpump) leaking, was when I had the synthetic Mobil1 in there. I've noticed that the shifters rod seal is also sensitive to what oil is used. There's a drip every now and then, but not like before, when oil gushed down whenever I removed the sprocket cover. Will Castrol's GTX High Mileage cure the typical - at least for a CB500 - sweating at the head? Not that I've experienced, but it hasn't worsened. It usually occurs after cold starts following a long period of inactivity and seems to decrease when I ride daily. It's not sweating to a point that I have to fear for my pants, so I can live with it.

it seems that castrol is syntetic?

To serve you well, I went down to the basement and had a look at the package. New to me: it now says 'synthetic technology'. Not on the old package. Nothing to worry about imo. 'Semi-synthetic' is a similar term.
 
* If a package does not say JASO-MA, it does not automatically mean that the oil doesn't meet that specification. It could well be that the oilcompany rather wants you to turn to their 'specific' and usually higher priced line of motorcycle oils. Who knows?

[Scott S]

HINT:- be very careful with the rubber boots from airbox to carb as they are different from 500 and other 550 and are also not available.

 The air box to carb boots for the '77-78 bikes are available. I can't remember the guys name but if you do a search on here you should be able to find it.