Another Pete Special!

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

BCF's resident mega machinist saves the day again.

The Old Trophy was leaking from from the rocker cover. Dad removed it to find 2 studs very loose. Turns out there was a mixture of Araldite and Body filler in it. Rolling Eyes

It even appears the stud may have been filed down to fit with all the shit in there. Pictures online show they have 7 threads mine only have 5 Laughing

https://img.photobucket.com/albums/v295/chris-red/FullSizeRender_zpsxbeulqoc.jpg

https://img.photobucket.com/albums/v295/chris-red/FullSizeRender_zps0hdwsbxl.jpg

https://www.feked.com/images/detailed/25/IMG_1242-600.jpg?t=1410338879

These are only tightened to 5lb/ft so dad gave it ago but they just pulled out.

I PM'd Pete asking for advice on what I should do about 15:30, at 18:30 I was in his workshop with a cup of tea and a solution.

First up was making studs, he found the only 2 5/16 UNC bolts he had and turned them down using the lathe, then cut a 1/4 UNF thread using the lathe (that still amazes me). As the part is little and the tool get so close to the collet/chuck we spent a lot of time with tight cheeks worrying the auto stop wouldn't and ruin a VERY expensive bit of kit.

https://img.photobucket.com/albums/v295/chris-red/18179DF9-31BD-409E-972F-24DC0FE071CE_zpsvlgemsje.jpg

Next was another scary part, there is bugger all metal spare in these cylinder heads. He had to drill the old holes out on the milling machine ready for a 5/16 UNC tap

https://img.photobucket.com/albums/v295/chris-red/B1B6DBD3-541C-4535-80E7-7042FBCB9EBC_zpsmxrl4wze.jpg

After we had done the 2 knackered ones Pete, check the mating surface for flatness, in short, it wasn't Laughing

It's a bit chicken an egg in my mind as to whether it wasn't flat so the studs stripped the thread or the studs were striped so the cover went out of true.

He offered to lap it as well, however this meant removing the other solid stud. Pete reckoned it was all right I must admit I had my doubts. Unfortunately I was right and the other thread crumbed too. However a dab hand now at make these studs he managed to find the ONLY other 5/16 UNC bolt in the workshop to make another stud.

The cover was tapped and lapped, and now better than factory. (Much the the brake lever pivot he remade for me also...) Tapping the third hole was interesting, Pete only had a starter UNC 5/16 Tap, so to tap the other holes he started them both off with the tap then cut the point off to make a bottom tap so he could make the most out of the limited depth we had. This mean the 3rd holes had to be cut with a flat tap!

https://img.photobucket.com/albums/v295/chris-red/7031E38B-705E-49D4-A727-DB3F8DED492C_zps9jklzlia.jpg

Unfortunately I didn't get any pictures of the finished article Pete has some he'll post or I'll get some later but I do have this one, it had been lapped with Grinding past and 7 micron Diamond paste. However the newly tapped hole needed finishing.

In short another problem where I was at a loss sorted!

https://img.photobucket.com/albums/v295/chris-red/29F1C3F1-8175-40CB-A92F-7BC9419618F7_zpsyzhhg4uc.jpg
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Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

Kris · World Chat Champion Joined: 03 Feb 2002 Karma :

Fucking legend as always Pete Thumbs Up

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www.prisonplanet.com

MarJay · But it's British! Joined: 15 Sep 2003 Karma :

Pete needs to post in this thread so we can uprate it immediately.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

..... · Quote Me Happy Joined: 15 Jan 2005 Karma :

Awesome stuff Pete Thumbs Up

P. · Red Rocket Joined: 14 Feb 2008 Karma :

When I see a Pete thread, I unzip in preparation. I was not disappointed, dem skills.

Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

Always fun to tackle an unusual problem.

The original studs were 1/4" UNC one end and 1/4" UNF the other. Reasoning is that the cast ally is less likely to pull the thread if it's coarser. Nowadays with better quality alloys you'll find that bolts fitted into ally casings tend to be fine thread.

Anyway, I had some 5/16" UNC bolts spare and most importantly a tap to suit them. So I made some studs at 5/16" UNC one end and 1/4" UNF the other. Had to turn the threads because the only 1/4" UNF die I had was a cheapo quality die-nut.

https://peterrimmer.myby.co.uk/images/tr6rockerstuds.jpg

You might notice that two are different to the third - that's because the bolts were of different material.

Only two of the studs had pulled but when I put a 1-2-3 block on the gasket face it was rocking badly so the face was definitely out of flat. This probably accounts for the pulled threads - someone must have over-tightened them to stop it leaking, stripped the threads then glued the studs back in. So we pulled the last stud with a pair of locknuts and found that it too was glued in with some concoction.

The face of the rocker cover was lapped flat on a cast iron surface plate. I had scraped this plate flat as a test-piece when learning machine scraping so I know it's flat to a couple of ten-thousands or an inch.
I started with a very fine paste but it needed some more aggressive grit so I used fine grinding paste and some penetrating oil to make a slurry. Three or four laps of about a minute each and we had the whole face dull grey so I switched to 7 then 5 micron diamond lapping paste and it put a nice even grey sheen on the whole face. That face is now flat to about half a thou (0.01mm)

https://peterrimmer.myby.co.uk/images/tr6rockerlapping.jpg

So we fitted the studs with red loctite and tightened them with two nuts locked together. Job done

https://peterrimmer.myby.co.uk/images/tr6rocker2.jpg

https://peterrimmer.myby.co.uk/images/tr6rocker.jpg
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good Very Happy

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

My job in the 'we' was supervising Laughing

____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

delsol · World Chat Champion Joined: 12 Apr 2011 Karma :

Impressive Pete, and interesting to see how this was tackled, resourceful and skilful. Thumbs Up

ferrisio · Scooby Slapper Joined: 03 Jul 2014 Karma :

fapfapfapfap

Beautiful work.
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BMW R1100R