CB550 First Build - Hondvarna?

[cinqmars2]

I also had a look at the tank which came off the crash bike, dented from every angle, some were fixable but others are completely creased and will need to be filled. I tried the 'hot-then-cold' method to no avail, that explains the singed tank in the last picture, but found success in hot gluing a piece of wood to the dent and yanking it out. Remarkable how flush that side is now!

 

[cinqmars2]

I'm beginning to get very concerned about the way I treated the frame and have decided to cut out some metal and replace with straight tubing, or perhaps even the whole of that triangle.

There's a thread on Do The Ton which features a bike that had no rear end, they just fabbed in a new a*se and it looks immaculate! I'm hoping to be able to do the same.

Does anyone have any advice or any concerns about doing this? I'd most likely build a jig to hold it all in place and keep it as  true as I can when it comes to it.

I have attached the bike from DTT and also some scribbles about how to go about cutting my frame, advice please! I'm thinking gussets may help spread the stress around too. Floundering...

[matthewmosse]

In reality a lot of these bikes will be running frames with more metal missing from rust than you have taken with the grinder. My 500 was really bad and was doing a lot of miles often at some speed and had a sidecar attached that adds to the loading on the rear subframe. I tested the thickness of the thinned metal by running a gas welding torch run over it - if it went red fast it was thin. I repaired by sleeveing in a smaller diameter repair pipe with a repair section of the same diameter as the removed metal so the butt welded repair was supported internally. The internal re enforcement was tapered off a few inches past the joint to avoid stress raisers. Plug weds were also used. I actually ended up re fabricating much of the rear end metalwork and was quite glad of my blacksmith skills as a fair bit of sheet metal bashing was needed to keep an invisible repair. For your project a simpler approach can be used. How is your welding? if it ain't spot on then a simple bit of gusset as you show might help but I'd leave as is.

[cinqmars2]

Thanks Matthew, that puts my mind at ease to some degree, I'll still fill the seams and chuck on some gussets just to be sure, want it to be stiff!

[kifer]

I wouldn't worry to much we all make mistakes the best way to learn I tend to use a linnesher to tidy things up cheap and not as aggressive as grinding discs Keep going you will sort it in the end and no problems in over doing it with gussets

[matthewmosse]

For cleaning up and removing bracketts I'd start by removing the brakett at a distance of about 5 -10mm using a cutting disk so as not to risk either cutting into the frame or wearing the disk out on the thick bit of weld, the grinding disk is far better and more cost effective to remove the welds once the bulk of the brakett is removed. For the final cleanup use a flap disk in the grinder. Having treated myself to a sabre saw from Lidl I'd really reccommend one for the cutting side of things, I was really pleased with the results the other day when I had to swap engines on my 125cc Honda rebel, the exhaust nuts were so corroded even a 9mm wall drive sockett didn't find any purchase at all, being flanged nuts they had gone pyramid shaped so mole grips couldn't get a decent purchase and a grinder would have been too close for comfort to the head and frame and exhausts if it could get near at all, I found it a doddle to cut the nuts diagonally through with the sabre saw though, then a simple job to insert a screwdriver in the slot and get things moving by giving a sharp tap. Nothing beats having the right tool for the job.

[cinqmars2]

Yeah you're right, I should definitely be more patient and save for the correct tools.

Since the last update I took to taking apart my carbs. These came from the crash bike and I have no idea whether they it was a 550K or 550F. Does this make any difference? The carbs were badly oxidised inside, the brass isn't too bad but the jets were clogged. A little bit of rust in the bottom of the bowls too, but that was easy enough to scrub out with a bit of carb cleaner. I boiled the bodies for a couple of hours in lemon juice, vinegar and water to great results, any brass that didn't have rubber involved was also boiled with the bodies. Some cleaned up but others have debris in that I can't shift. I don't have access to an air compressor in the area but have read about using a softer metal to try and move any dirt in the jets, copper wire maybe. It's really not something I want to do so may just end up buying a rebuild kit. the only one I can find is from DCC which, of course, involved US shipping costs. I deem it well worthwhile to pay for it, but if anyone is after anything from them and can't justify the shipping, it may be an option to chip in on the same order...? Just a suggestion...

Looks right, anyone got any insight?

http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-engine-parts-honda-cb550-carburetor-rebuild-kit-18-2422.html

[matthewmosse]

k3 carbs are qute different and give better fuel economy than the f ones and I'm pretty sure the jetting is different as are the fittings for jets I think so I'd advise finding out before spending money. I've found the k3 jets block easily, Only other carbs I have had are the 500/4 ones that are thirstyer than my k3's but seem to not clog regardless - I've even had a set that were awsomely filthy work well enough to get an engine running on my workbench. Try NRP carbs in uk if you havent yet? It was a while ago but they were pretty confident they could get any carb parts even for the k3.

[cinqmars2]

Ok, good to know! Do you think anyone would be able to identify the ones I have if I post a picture? I'll get some up when I get a chance, unless anyone can advise on any stand out features that would differentiate them?

[Mitchv60]

Yeah you're right, I should definitely be more patient and save for the correct tools.

Since the last update I took to taking apart my carbs. These came from the crash bike and I have no idea whether they it was a 550K or 550F. Does this make any difference? The carbs were badly oxidised inside, the brass isn't too bad but the jets were clogged. A little bit of rust in the bottom of the bowls too, but that was easy enough to scrub out with a bit of carb cleaner. I boiled the bodies for a couple of hours in lemon juice, vinegar and water to great results, any brass that didn't have rubber involved was also boiled with the bodies. Some cleaned up but others have debris in that I can't shift. I don't have access to an air compressor in the area but have read about using a softer metal to try and move any dirt in the jets, copper wire maybe. It's really not something I want to do so may just end up buying a rebuild kit. the only one I can find is from DCC which, of course, involved US shipping costs. I deem it well worthwhile to pay for it, but if anyone is after anything from them and can't justify the shipping, it may be an option to chip in on the same order...? Just a suggestion...

Looks right, anyone got any insight?

http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-engine-parts-honda-cb550-carburetor-rebuild-kit-18-2422.html

I don't know if this is any help but I've just had my carbs sorted.As I've never worked on the internals before I gave them to my trusted mechanic.He had to ultrasonically clean them 5 times just to get them apart,he said they where the worst he had ever seen.He then soaked them in used oil over night and then cleaned and stripped.
The emulsion tubes where rotten apparently,we used the service kit from davidsilver.He was impressed with the kit because he said normally you don't get half the bits in them.
Just finishing off the rusty cosmetic parts and then there done and back together.

[cinqmars2]

So, it's been a long while since my last post, and there is really nothing to report since that time...

With my last day of Christmas and New Year freedom before going back to work, I took out each and every part and catalogued them all. I photographed everything and have noted down all parts and their condition.

The main thing for me, is the idea of combining parts from the two engines I have.

The original (Engine 01) has been promised as a good runner.

The second (Engine 02) has been partially dismantled, cylinders off etc, crank case and gearbox intact.


Engine 01 has a few chipped fins and a couple of cracks, but supposedly works as it is. Engine 02, although rattier, is complete with no cracks at all. Would it be advised to replace the damaged parts of Engine 01 or would it be best to keep a run-in engine together as a whole? Could there be wear variation between the two that would cause more problems? Or should I focus on just rebuilding Engine 02 and make that my primary?! I could split the case, get it media blasted, painted etc as it's already half disassembled?
Sadly the only box of parts I haven't documented yet is the one containing the cylinders and head from Engine 02. Will get round to that tonight.

[cinqmars2]

Some photos of Engine 02.

[cinqmars2]

Also some photos of my carbs for help with identification 

This is after a good lemon juice + vinegar cooking, all need a full rebuild.

[Bryanj]

Those carbs are the same as fitted to all 500/550 EXCEPT the K3, and whilst they runn richer are far easier to stip/clean/get parts for

[cinqmars2]

Those carbs are the same as fitted to all 500/550 EXCEPT the K3, and whilst they runn richer are far easier to stip/clean/get parts for

Ace! Thanks Bryan, appreciate the help!