A forum for owners of Yamaha TTR250 trail and enduro bikes!

So is there a factory engine paint/spray thats on the market that i can purchase which matches the original.

Regards

Hi there - thought I'd share this for a fairly quick easy and very good result from a spray can...

The cam cover on my TTR was a bit crusty with some areas of the gunmetal paint on the alloy lifting, kind of like small areas of corrosion. I wasn't happy with it and decided to tidy it up.

While I have a compressor and spray gun and can spray enamel, lacquer or 2-pot, I wanted a high heat paint and the convenience and speed of an aerosol. While 2-pot might be popular with its "hardness" (from the hardener) that characteristic can be a weakness in that it can be more prone to chipping (like lacquers), whereas the pliable (softer) nature of enamels absorb damage (stone impact) better and are therefore more resistant to chipping.

The challenge was in finding a good colour match off the shelf from the various brands available. After a lot of searching I eventually found VHT Engine Enamel in "Cast Iron" to be a very good match to the factory engine paint colour, if not 100% perfect.

I do not sand blast alloy engine parts - too aggressive and will likely damage or "pit" the alloy. The factory engine paint is actually quite thin (best for not breaking down under heat) and looks like it has a clear coat over the gunmetal colour. I used an ordinary domestic gel/liquid type paint stripper applied with an old fine toothbrush to remove most of the factory paint - zero damage to the alloy. Give the stripper a few minutes to work then rinse off with the garden hose squirted at pressure.

Allow to dry then finish with some sandpaper by hand (carefully) - I used 180 or 220 grit dry. That took any residual paint off and also provided a good enough "key" for the paint to be applied. The primer filled any imperfections or sanding marks from that grit. If you go too fine on the sanding the paint will not stick or "bond" to the surface so well and can chip off in chunks more easily, although obviously you don't want any deep sanding marks.

I used only one thin coat each of the VHT Engine Enamel Primer, Cast Iron Colour coat, and Clear coat. We're having nice hot days down here in NZ at the moment (28 degrees Celcius) so good for getting the aerosols nice and warm before use for best results (the paint is thinner and flows better when the can is warmed up - an alternative is to put the can in a jug of hot water before use). Shake very well for a good minute or so before spraying.

Try to keep your coats as thin as possible while achieving good coverage, just dusting short bursts from say 10 inches distance to avoid runs and excess build up/paint thickness. I found the primer did not even need sanding (that depends on the quality of your underlying prep though of course). Allow 30 minutes between coats (in warm weather - maybe more in colder weather). I was able to leave the cam cover in the sun outside here at the moment and it got very warm to the touch each time, which is helpful.

On the can VHT recommend "curing" the finished paint in an oven at 200 Farenheit or 93 Celcius for 1 hour. Although this is optional, it provides a stronger finish with better resistance to chemicals, so I did it. The paint needs to be completely dry before doing this step - that would normally have been say 24 hours, but in my case I did it after about 4 hours of drying in hot sun.

Pics of the result are attached. The colour match to original is good enough for my liking. I think it has a little more "metallic" in it than the factory colour, but the difference is so small I can live with that.

The first 2 pics were taken in daylight outside and before the clearcoat was applied. The last pic was taken indoors at night after the final clearcoat, just before popping it into the oven for an hour. I'll upload some more pics once it is refitted to the engine for a better gauge of the colour match.

Cheers

-- Edited by The Vivinator on Sunday 7th of February 2021 06:53:56 PM

Hi there Martyn - nah, I'm a Barrister actually, lol.

My Dad was a builder and fairly handy with a range of skills - he taught me how to spraypaint my own cars when I was a teen in the early 80's. Started with enamels (a quick easy squirt with finish off the gun, but easy to get runs so a high skill level required), then lacquers (harder to spray and get a gloss off the gun with a lot more work involved cutting and polishing = better end result with greater depth of shine/glassyness, but more susceptible to chipping), then 2-pots (easier to spray with a finish off the gun, better metallics, but contains isocyanate so very nasty from a health perspective, air-fed mask required).

Thanks for the offer but I already have enough projects on my plate for the forseeable future, lol.

Cheers

Ok, so here are some pics of the cam cover placed next to the crankcase and sitting in place on the cylinder head ...

The Yamaha engine colour has a blue-ish tone to it compared next to the VHT Cast Iron colour. Obviously that difference would not matter if you were repainting the whole engine, and it is close enough for me when doing the cam cover which is separated from the block by the cylinder cooling fins.

-- Edited by The Vivinator on Monday 8th of February 2021 07:02:42 PM

-- Edited by The Vivinator on Monday 8th of February 2021 07:03:57 PM

-- Edited by The Vivinator on Monday 8th of February 2021 07:07:43 PM

-- Edited by The Vivinator on Monday 8th of February 2021 07:13:15 PM

-- Edited by The Vivinator on Monday 8th of February 2021 07:15:50 PM

-- Edited by The Vivinator on Monday 8th of February 2021 10:42:14 PM

Once it gets dirty, you will never notice