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I'm in the process of rebuilding the top end in my 1982 Suzuki gsx400f. It's got quite a lot of carbon build up in the combustion chamber that I want to remove and clean them up good.
After that I'm going to try and re seat the valves, change the valve oil seals etc.
Anyone have any tips for a good treatment to help break down the carbon?
I've been trying brake cleaner, wd40, swarfega degreaser, gt85 but generally nothing really touches it. I've also been trying to shift it with a brass brush on a Dremel.
What do folks use?
I've got a cylinder hone tool on order which I'll try to use very lightly when I remove the carbon from the top 4mm or so of the cylinder. I also want to remove it on the piston tops.
I have always used a brass brush on a Dremel, now quick but I don’t want to risk damaging it by using a steel brush.
Slow and steady is the way forward
I've always used a selection of small scrapers and Scotchbrite pads. The engines I've had apart I've avoided using anything mechanical for de-coking. The other option is vapour blasting. I haven't found anything that will dissolve the carbon without affecting the alloy IE caustic soda.
Elbow grease and midnight oil for you!
I don't mind using the Dremel and taking my time, but was a bit worried that the areas I was doing seemed to be getting a slight brassy shine, as if the brass was slightly depositing itself on there.
I think maybe keeping it squirted with wd40 helps.
Oh, and one of the studs sheared inside the head so I've got to tackle that too. 🙁
I'd be wary of using anything mechanical. If you use FB search for Practical Sportsbikes Magazine,lots of people doing restorations on there so someone should know what to use.
I'm surprised at it being full of carbon,what's caused it?
As far as the cylinders are concerned, a Stanley knife blade used so as much of the blade as possible is touching the bore and in-line with its axis works a treat. It can also be used to scrape most of the crud off the valves as they are pretty hard and take some damaging. The head is another matter entirely, I have some Dural scrapers from my aircraft days that can be used carefully, you want something with a radius on the end. Get a small section scraped down to bare metal and work from there. If you don't try and take too large a section off at a time a lot of it usually flakes off fairly easily. A selection of different materials with different end profiles and patience!
Good luck.
Scrape with wood
I use a home made soda blaster.
Soaking in diesel can help, so can a hot pressure washer at a car wash......
Methylene chloride will take carbon deposits off, this is what's in proper paint stripper.
I haven't used it for years, I used to take heads round to a mates, he did headwork and had a sink of methlene chloride he cleaned heads in; he left them overnight and then cleaned them with a pressure washer.
I wouldn't go near any aluminium with any sort of powered wire brush, I use a gasket scraper and other scrapers
ground from machine hacksaw blades. Once clean a rub with scotchbrite gets small stuff that won't scrape off off. If you want something in a tin look up wurth gasket remover, I am told it strips powder coating so might well take carbon off.
I wouldn't run a hone/glaze breaker unless your stripping it and reringing it, just scrape the carbon off.
Here's some pistons I recently cleaned to flog on ebay. They are just scraped and a rub with a scotchbrite.
I’m surprised at it being full of carbon,what’s caused it?
Not sure. I thought it was relatively normal to find pistons like this but it's a nearly 36 year old bike. It's under 20k miles too so I suppose it's done a fair bit of standing around.
I wouldn’t go near any aluminium with any sort of powered wire brush,
I won't go near the head or any gasket surface obvs, but it's ok in the combustion chamber around the valves?
If you want something in a tin look up wurth gasket remover
Roger that, thanks. Those pistons look sparkly clean 🙂
I wouldn’t run a hone/glaze breaker unless your stripping it and reringing it, just scrape the carbon off.
I'm sure you're right. I'll see if I can shift it using a plastic scraper or something. I do have the head fully off so all the pistons and rings are there in the open. I may remove the pistons altogether to clean them I think..
I have just done my GSXR1100, the pistons and head were caked in carbon, I used oven cleaner on the piston tops and combustion chambers, just don't leave it on for too long, half an hours probably enough too start to loosen it, then rinse it off with lots of water.
I used a decoking wire brush on a die grinder for the inlet and exhaust ports, took all the carbon out, but wasn't aggressive enough to start removing metal.