Hello all, So, I brought a 2011 Triumph Street Triple at the start of this year, I’ve just taken all the fairing off ready for a thorough clean. The bike looks to be in mostly good shape, but upon closer inspection there seems to be some pretty bad corrosion around the cylinder heads, where the exhaust meets the engine, just behind the radiator, the paint is blistering and flaking off quite badly. I’ll get some pics up later, but should I be concerned? Also, the exhaust studs are in pretty bad shape, nuts are very rusted. I’ve been lubing them up and gently trying to move them, is this wise or should I leave them be? Its in my nature to replace things like that if possible or clean them up rather than ignore it. It almost looks like leaks around the exhaust gaskets have caused the corrosion on both the studs and engine but I don’t know, I’m just a little worried. Any info is appreciated, thank you! Regards, Dom.
Normalish for these areas to corrode, I think it's due to not cleaning these areas, and corrosion getting a start under the coatings, If you post photos they may rule out leaks completely. The studs will corrode because of the hot cold cycle they are involved in. I can't recommend fixing stuff that isn't broken. Although I would want to replace them too. They won't improve. World of Triumph are a resorse, although expensive. The Alloy corrosion on the block is probably best cleaned back to metal and painted.
Thanks for the quick replies, I’ll get some pics uploaded tonight, both as it sits now and after I’ve cleaned it up. I was gutted when I found the corrosion, didn’t expect it at all as the bike looks pretty nice overall.
Just remember this is cosmetic........on a 7 yr old bike. The powdery aluminium oxide corrosion is itself a very effective barrier to further corrosion. The problem is that it will track under the powder coat and lift it. It is an awkward spot to access but your choice is really to monitor its spread until you cannot live with it (or choose to sell the bike) and/or cleaning back to bare metal and painting with an aluminium primer and high temp gloss black to match. It is a small wire brush/Dremel/skinned knuckles sort of job......
Cheers pal not heard of that combo before, I’ll give that a try, been soaking the rusted nuts/studs in AC90 for the past few weeks, not even tried to remove them yet, or even if I should, but I’d like to. ACF50 will be used often now I own the bike, looks like the previous owner was pretty lazy regards to cleaning. The bike has full Triumph service history though, with more stamps than it needs, so hopefully its been looked after in that sense. Looks like the corrosion started around the rubber pipe behind the radiator as shown in pics. I’ll need to remove the radiator to gain better access, and as suggested clean it, rough it up and repaint. Does it just look like regular corrosion from exposure or could there be a problem? Cheers.
Cheers pal not heard of that combo before, I’ll give that a try, been soaking the rusted nuts/studs in AC90 for the past few weeks, not even tried to remove them yet, or even if I should, but I’d like to. ACF50 will be used often now I own the bike, looks like the previous owner was pretty lazy regards to cleaning. The bike has full Triumph service history though, with more stamps than it needs, so hopefully its been looked after in that sense. Looks like the corrosion started around the rubber pipe behind the radiator as shown in pics. I’ll need to remove the radiator to gain better access, and as suggested clean it, rough it up and repaint. Does it just look like regular corrosion from exposure or could there be a problem? Cheers.
Any resident metallurgists? I suspect the issue is simple galvanic corrosion. Basically you need steel studs to hold the exhaust on an aluminium casting. The two metals conduct electricity differently and that difference in ‘potential’ means one corrodes ‘preferentially’ - like a one way chemical flow. Throw in an electrolyte (a conductive solution) like salty water and the process accelerates. If the surfaces are clean and then coated (ACF50 etc.,) you inhibit the entire corrosion process.
Appreciate all your responses, if it is just cosmetic and common then that puts my mind at rest, I did purposely buy a cheaper bike with higher milage because its my first big bike and only form of transport so will be used for commuting all year round. That being said I’d still like to fix it up best I can, I’m the OCD type so if I know its there it will bug me, even if its not easily seen. If I can clean it up, paint it, and get some new exhaust studs in I’ll be happy. Should I just sort the bits where paint is peeling or rub down any blisters etc before they develop into something worse while I’m at it? Also, with it being small patches here and there, would it be better to apply the paint with a brush rather than aerosol, and is primer or adhesion promoter necessary? Cheers.
I would strip down the area for ease of access and rub down anything suspect having probed with a flat blade screwdriver. That will reveal corrosion blisters rather than just rough finish. Mask off and use a brush. Less messy and ‘good enough‘ for under there. The big thing is getting back to bare metal, cleaning off with acetone (her nail varnish remover!) and using an aluminium primer. High Temp gloss last....
I take it the primer must be heat resistant too, and be suitable for aluminium, have you got any suggestions? I found a few aerosol varieties but nothing that comes in a tin, and the ones that do come in a tin don't seem to be heat resistant.
Or similar https://www.amazon.co.uk/500ml-Silver-Aluminium-Resistant-Temperature/dp/B00AC2206I Or https://www.amazon.co.uk/XtremeAuto...coding=UTF8&psc=1&refRID=MC8DM83SZ57A3X921FZR See double deal incl black gloss scroll down Otherwise this stuff you can spray and brush on https://www.halfords.com/motoring/p...oniz-silver-very-high-temperature-paint-500ml Your surface temp should not greatly exceed the cooling water under pressure just over 100C but adjacent the exhaust ports it might be a bit higher.
On a last note, these days aluminium used is just recycled shite that why it’s always painted. I’ve an old eastern block Mz in bare aluminium been stud in a wet garage for 20yrs (before me) with virtually NO ENGINE CORROSION! That’s because recycling wasn’t as popular and only quality virgin aluminium was used.
Except your virgins have been corrupted too. Almost all of the aluminium used is/are alloys containing silicon, copper, magnesium etc., to give it the desired properties. Recycling does not mean melting and pouring any old iron without checking the recipe. Your MZ probably had a good chunk of zinc in it. My old Ossa was similar.......and quite brittle as I found out!
Mazda too. You should look at the underside of a 6 yr old MX5 but the effect is almost entirely cosmetic on the hubs and spars.
Square Deal has stainless steel studs and they are very well made, I also found all metal stainless locking type (torque prevailing) nuts one Ali Express although you will have to wait a few weeks for them to come from China. Jim.
