The Hodaka Club Forum

greetings all -

I am trying to recondition a 20mm Mikuni for a Steen rehab project, and there are several parts that just won't budge at all. The float pin can't be tapped out (it might be a clipped nail), the pilot jet shows no signs of turning, and the main needle jet also can't be tapped out. I think these parts are all seized by corrosion, as the overall internals of this carb were significantly caked with a sand-like layer of junk.

I have tried solvents such as brake cleaner, PB blaster, cider vinegar, and currently soaking in pine sol, as well as a few cycles of freezing and thawing, and some heating via hair dryer. so far all of these have failed (still soaking).

does anyone have any suggestions on other methods I can try? I don't want to risk damage or breakage of the body in ways that will render it useless, and there is even a chance it will function as is after cleaning. the only heating tools I have available are a normal plumbers type canister torch and a couple of soldering pencil/guns of relatively lower wattages.

thanks for any info,
steve z.

You could try soaking it is carb cleaner or locate a facility with an ultrasonic cleaning system and ask them to give it a whirl.

I think maybe heating in your oven at 350 degrees for about 20 minutes might do it. That's how I heat cases and hubs and stuff to drop in bearings. And of course use the best fitting tools you can. When it's hot you might be able to get a grip on the pin with needle mode pliers and twist it loose. Got to be careful driving them out or you could break the carb pin bosses.

That should have said needle NOSE. Stupid autofill keyboard...

Hey Steve, All of the above. I did finally did get float pin out by putting a soldering gun on it, some of the crud does melt. Best of luck, patience is part of it. Lacquer thinner is mean on some of the stuff. Been there!

Maxie

I just went through that same thing last month, scored a complete and encrusted 20mm carb of eBay that was frozen solid. I too ended up soaking it in full strength Pinesol for about 7 to 10 days (makes a garage smell really nice too) and rinsing it with hot water and then using a hairdryer to heat things up. Some things came off on day 7 others needed to soak more. I did that each day and eventually it all came out great and serviceable.

I think you’re on the right track. Patience pays dividends.

Bev

Also some of the more effective penetrating oils might help. I prefer ''Kano-Kroil". A bit spendy and unfortunately not widely available, but very effective. I get it off Amazon.

Don't heat a carb past 212 (boiling water). Some of the Mikuni carbs used on Hodakas have a plastic guide/anti-rotation "pin" for the slide. Boiling water temp should cause no harm - and should be helpful. Higher Temps increase the risk of damage.
Ed

thanks very much for all those responses. sounds like a good plan will be to continue soaking since I am basically on day 2 with the pine sol. the cleaning is going very well otherwise, so I think some heat will be a good idea to try next and nothing hotter than boiling water. and probably need to fashion a really well-fitting screwdriver for the pilot jet too.

steve z.

I've used PineSol and water mixed 1:1. I think lowering the viscosity helps the mixture penetrate better.

Dwell time is another factor. For every 10 years the carb has been sitting think of having to soak it for at least a week to reverse the situation.

thanks Darrell. making some progress - using a little jig to brace the posts and a spring loaded punch at lowest tension, I was finally able to get the float pin out. as suspected, it's a cut-off nail. with some further soaking, the main jet needle came out tonight. the last and hardest part will be the pilot jet, and I still have to fashion a good tight screwdriver for that.

It is nice to read your progress reports and to see the success which comes with patience, attention to detail and steering clear of brute force techniques.
Ed

Now I'm feeling a bit cheezy about the two of my Hodie stable currently running with cut-off nail float pins.

Ed - Amen to that ... I have no pressing timeframe for this project (one of 3 Hodies in progress), and I think that is a major factor in not forcing the issue(s).

Matt - in many times past I would have done exactly that, but now that I've seen the havoc that can happen between plain steel and aluminum, I'm very sure I will remember to avoid this in the future!

steve z.

Steve, I have already already replaced the nails with proper pins after reading of the DPO shenanigans you are sorting out . Yet another example of the wages of corner-cutting.