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Post by slowracer on Jan 15, 2020 10:42:53 GMT 1
Morning, been lurking on here for over 4 years, since picking up a non matching numbers 250 LC. 4LO frame, 4L1 motor. The bike became an ornament in the hallway and was dry stored there up until an alcohol induced moment in the garage, when I dragged her in and decided to recommission. A nut and bolt rebuild, yes, a purists genuine oem parts rebuild, no. The bike will be paraded at classic race meetings by the wife and she likes shiny stuff ! So, after much powder coating and polishing, it is almost a rolling chassis, and now time to look at sprucing up the motor. I've read many threads over the years on here and really appreciate the tech stuff, as it saves me time and helps me avoid the pitfalls. The motor doesn't scare me, I'm ok with the spanners ( I race classic bikes, so have to be) but first inspection shows a few cosmetic challenges, that I can't find on a search of the forum. Painting is never uppermost in a racers mind as it equates to the price of tyres, so rattle cans or colour impregnated fairings are favoured, so I know nothing of what to use on which surface ! For now, I will go with the first question, which is what to use/how to paint the oil pump cover. A previous owner appears to have painted it to match the cases, but this has bubbled due to being left in situ over the water pump for a few years. Twisting the plastic cover, cracks the paint and looks to reveal a grey primer under a satin black top coat that looks like BBQ paint Any tips on cleaning the remnants off the plastic cover without damaging it and then as above, what to put on and how to ? I should say that the bike is never going to be a concours show winner, but it has to be right, so any help appreciated.
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Post by oldbritguy on Jan 15, 2020 11:17:45 GMT 1
Hi and welcome into the forum (at last) painting plastics is always a bit tricky. I have had some success with Plastikote paints from B&Q and also had good results using car bumper paint available from just about every car accessory shop. If you are looking to get the old paint off and repaint then steel wool, fine wet and dry and sore fingers will do the trick. Some of the guys on here will no doubt share their own tips as well You could also save yourself the bother and buy a new cover. Norbo has them in his shop but a little expensive. He also has loads of other gen Yam parts which may help you along. If you are going for a concours rebuild then you know it aint gonna be cheap. rdlccrazy.co.uk/html/for%20sale%20page%202.%202%20350lc%20.htmBe aware though that the shop is a dangerous place and will quickly separate you from the contents of your wallet, but the exchange is very satisfying Get some pics up too as you know we love a rebuild/resto on here John
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Post by Deleted on Jan 15, 2020 12:00:06 GMT 1
I've done the plastic left hand or stator cover initially using a purple fleece (320 grit) sanding drum on a 12V drill to take off the original coating and remove any minor scratches
Then I wet sanded it with wet and dry and dishwashing liquid with 500, then 600 then 800 grit , then washed it clean with soapy water, rinsed and then wiped over with prepsol
Then I used a proper plastic filler to fill any major scrapes and repeat the sanding and cleaning process
When you sand or other wise abrade plastic it secretes an oil, the prepsol removes this and allows the filler and paint etc to stick
This final stage is important, wear nitrile gloves without the powder, if you touch the cleaned plastic you will leave your oily finger prints on it and the paint etc won't stick, the same applies to any unpainted surface
Then I use a plastic primer, its clear, then plastic bumper primer and if I have to a high build spray filler, again I sand the bumper/high build primer with 600-800 soapy wet and dry, this time I rinse with water only and dry with a clean rag and then use a tack rag to pick up any dust left behind, do not use prepsol or solvent cleaner at this stage or you will remove all the layers of primer etc and you have to start again, how do i know that - you can guess
I then use 2 pack spray paint, (it costs me about 13 quid a can) in a self made spray booth of clear plastic and an el cheapo lazy susan and paint the part
My cover came out pretty good, you can see its been attacked by a can of spray paint as there is a little bit of mottling, however a fine cut polish will take care of this
Its a labour of love, and it does take practice to get the right amount of paint on the object to get it to flow without runs, however it can be done, I'd be doing a few pieces at once as once you start the paint process its desirable to use the whole can of 2 pack as any paint left in there will go off after about 6 hours
I did the L & R covers and a top case in it, the R cover and top case came out real good with no mottling
It did take me two goes at it to get right and at all stages of the process, however when you consider the cost to do buy these parts its "sometimes" cheaper to try it yourself
In my experience single pack Acrylic gloss paint never really stays gloss more than an hour after it dries, that said I did use VHT black gloss caliper paint on my calipers a week or so ago and they are still gloss and I can still use the contents of the can
BTW I'm not a spray painter by any stretch of the imagination, this process works for me
On bigger panels or tanks I get in the professionals, although others here have done them with rattle cans too
If you look at the rebuild threads on here you will see whats possible, I can't (read maybe won't can't be bothered) post pictures on here, jonw's "garage art on the cheap" threads show you what can be done if you have the time and patience
Good luck and have fun doing it
HTH
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Post by slowracer on Jan 15, 2020 16:16:36 GMT 1
Thanks for the replies, much appreciated.
All tricks and tips help me get the best.
Although I have to say, the hblair method of productivity is astoundingly detailed and something that I would struggle with !
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Post by arrow on Jan 15, 2020 17:31:31 GMT 1
Welcome in.
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Post by midlifecrisisrd on Jan 15, 2020 19:02:31 GMT 1
They can be a pain in the ass
Had one that kept reacting, took half a dozen attempts
I did tend to buy new ones but the price has got ridiculous
Sad day when a carbon fibre one is cheaper than plastic š
Steve
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Post by pdxjim on Jan 15, 2020 19:11:07 GMT 1
Wet sand to 2000, then buff on a slow wheel no rouge.
Finally, a few applications of the āplastic trim restorerā juice of your choice.
DO NOT ATTEMPT to ābring the color backā with a heat gun or it will be fcuked beyond repair
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Post by liffy16 on Jan 15, 2020 21:19:00 GMT 1
Flatted marks out with 400grit then 800 then scotchbrite then left to soak in degreaser for a week and turned out ok
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Post by JonW on Jan 15, 2020 23:16:17 GMT 1
DO NOT ATTEMPT to ābring the color backā with a heat gun or it will be fcuked beyond repair I agree, fekd one of mine with heat. dont do that...
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Post by slowracer on Jan 16, 2020 13:18:29 GMT 1
DO NOT ATTEMPT to ābring the color backā with a heat gun or it will be fcuked beyond repair This saved me a very bad night in the garage last night, thanks.
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Post by wangwang on Jan 16, 2020 13:38:08 GMT 1
I did mine on a wet pumice wheel at work, took all the paint off without doing any damage, also takes out light scratches, then used bumper shine, looks pretty decent now.
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