400/4 Gunked up carbs - Help.

[Rozabikes Tim]

Checking out why newly acquired 400/4 will not start. Not run since 2004. Spark seems fine but carbs very gummed up.

On stripping them, all floats  were seized solid. Have got them moving but cannot remove pivot spindles to strip them down further. Reading the site a good soak in cellulose thinners seems favourite.

Any other advice please?


Tim

[K2-K6]

I've always found "PlusGas" good, don't know what's in it but it seems to get more tings than most unsiezed.

Also if you've got one a wallpaper steamer to safely heat and disolve gunky stuff can be quite effective.

[randka]

Total cycle cleaner S100 is good, recently had my carbs stripped down , all I can say is if you think something needs replacing do it, I thought I could get away with giving the brass a thorough clean but sometimes you have accept items need replacing, bike was running great to start with but now I have the carbs off again to replace the pilot jets and float valves, all great fun.

[exvalvesetdabbler]

The only way that I got mine out was to apply local heat with a small pencil size gas soldering iron using the hot air attachment because the gum/varnish was holding them tight. Once you get them hot enough to soften the gum, push them out with a small allen key or similar. Trying to soak them in any solvent just expands then gum and makes them even tighter.

I found that soaking each carb in  methanol for a couple of days would break up the gum enough to get most of it off with a tooth brush followed by a few hours in an ultrasonic bath.  Don't waste your money on carb cleaner aerosols,  it just evaporates to quick to do any good.

Also see one of my threads from last year about corrosion of emulsion tubes caused by the gum.

DJW

[Rozabikes Tim]

Success!!!!

Thanks guys for all the advise. Got the cabs stripped tonight with help from all your tips.

Once in bits, I have to say that cellulose thinners is easily removing the built up fuel residue. Also I am investing in an ultrasonic cleaner this week and once fully stripped of all the crud, I will try them in this new toy. I saw the result s "buxton mick" has got with his cabs - very impressive.

Once the cabs are sorted I will get them back on the bike and do some miles on it to check the motor etc out prior to full strip.

Thanks again for all the help offered.