Triumphrat

delrazor · 08-13-2009, 05:30 AM

So far I have found no major issues. There is no discolouration on the crank or gear shafts.

One gear tooth is chipped (about a third of the contact edge is effected). I found the bit as you would expect.

I expect something interesting with the gears as it was a factory 5 speed in 71, and I have absolutely no doubt that it wouldl have been replaced at some stage.

still using leaf spring.

The thick spacer behind the rotor didn't seem to fit neatly anywhere...just floated about on a spindle much narrower than the interior diameter.

the main bearings seem smooth and tight and the conrods only move laterally.

top end
- ring gaps measured an inch down - left - 0.7, 0.75, oil-1.1
right - 1.7 (yep!), 1.1, oil-1.5

right bore- 10mm from top - 72.09, 50mm from top - 71.88
left bore much the same.

front sprocket (20 tooth) all the teeth are bent forward.

the clutch studs (the ones that plewsy forgot) have been welded in place. Two have broken their welds.

the clutch seemed to have two large spacer washers. One against the other.

That is all I have for now.

cheers
derek

delrazor · 08-14-2009, 05:29 AM

cams
ex - forged : 71-0042 stamped: 70-9990
inlet - forged: 71 - 0040 stamped; 71-1063

does anyone know where I can see correct codes for a 71 t120rv?

derek

Woody1911a1 · 08-14-2009, 05:47 AM

here

http://www.postdiluvian.org/~mason/moto/cam-timing.html

cheers , Woody

delrazor · 08-14-2009, 07:00 AM

cool, thanks Woody. Looks like I have the right ones in there.

I took the head to 'the man' today and the guides are tapered, as are the valve stems.

The barrel is going to .060 with new pistone, etc.

I am also sending the crank off for a bit of work including a dynamic balance. The wear on the shells was a bit uneven and there was a lot of shallow scoring.
Small ends are diabolical. Someone has doen the top end twice and ignored them.

The sludge tube acces screw looks absolutely untouched, with the punch intact. The conrods have been off, so why the tube wasn't done after maybe 80000 miles I couldn't say.

72TIGER-X · 08-14-2009, 07:16 AM

good link woody
i saved it so when it comes time i can see what cams i have, i'm not sure if they are std because a PO has spent the money on a "4 plug head mod", would anyone do that without other mods?

delrazor · 08-19-2009, 10:00 AM

Ok, it is about time I started my own thread about the ongoing saga of my bonneville.
As requested my GPZ I will copy the blog to here.
I have done this before with scooters and found it invaluable for several reasons. Firstly people with more experiance can pull you up when you are heading in the wrong direction. Secondly you have a record of what you did, when and what it cost.

meanwhile the blog has begun and is here...
http://dirtystriumph.blogspot.com/

also I wouldn't mind knowing if the photo's from the blog can be seen here by someone not signed in to blogger.

eg....

delrazor · 08-19-2009, 10:46 AM

The story so far ....Initial findings

Things I had to do immediately to use the bike.
1- change all fluids
2- replace front wheel. A p/o had bashed in a lh thread locking nut and cracked the hub.
3- New battery
4- rebuild forks, handle bar mounts, clutch cable, clutch mechanism, speedo mount,
5- steering head bearings
6- reline fuel tank to stop leak
7- front brake cable
8- rear brake shoes
9- replace blinkers
10- rewire switches
11- align rear wheel.
More when I remember ....

The rise and fall of the dark lord as a daily ride
The bike ran ok. Pretty rich and not super powerful, but coming off a 150cc 50 year-old scooter it seemed pretty good.
In an attempt to tune the carbs up I rejetted, changed air filters to old style, changed to milder pipes, rejeted again.... I ended up getting some accurately re-machined amal 930's with hand made slides. Very nice, but still fouling plugs and backfiring.
A friend brought in his Bonnie of the same year to my workshop for me to change his oil and his kickstart shaft. I rode it and was amazed at the available power. Meanwhile, with the quieter pipes, I could hear some whining sounds coming from my engine when hot. Power loss when hot led me to the fear of a spun main bearing or soft seized piston.
TIME FOR A REBUILD..... to be continued .

Sometime you gotta make a stand.
The top end came off first. It looked surprisingly fine with no scores, cracks or holes. Just carbon, and plenty of it. Upon further inspection I found the following. ....
Bores larger near the top
Ring gaps as big as 1.5mm. (should be 0.24) This to me means the wrong ones were installed and confirmed the dire need to pull the whole motor down.
Small end bushes very sloppy.
Valve stems tapered
Valve guides conical.
Valves were sealing very well.
One bent head bolt
One stripped rocker box bolt hole (in head).
Blue silicone inside the top of head around the valve stems.

I made the decision to get the head done professionally, and get the bore done with new pistons, rings etc.
MEANWHILE...... the big end awaits inspection.

big End
not too bad.
Despite all the talk from a p/o about rebuilds etc., the sludge trap appeared to have never been tampered with . Centre punch mark intact and not a mark on the screwdriver slot. The small ends have never been changed despite several re-bores, and the con-rods were on backwards. I am told this is not that relevant but does indicate that they have been removed at some stage.
The machinist reckons we may stay in spec on the journals as the ridging is very very shallow.
both crank bearings seemed fine. I cleaned them out thoroughly, lightly oiled them and they were smooth as.
I have ordered new ones anyway. Seems like the right thing to do.
cam bush movement is negligible, so they will stay.

The gearbox sprocket was a 21 tooth and each tooth resembled a surf wave. I have ordered a 19 to put back on. Normally I would have stuck with the long gearing to reduce vibrations at higher revs, but I have sent the crank off for dynamic balancing, so I hope to enjoy the best of both worlds sometime this year. I also expect to leave Marcus' 71 bonnie in my dust, but that is another story.

that all pretty much brings the story into the present tense. Tense being the operative word as I reassemble this beastie.......

RIGHT NOW
my first post in the present.
Summing up.

cylinder - at machinist
head - at machinist
Crank - at the balancer
the rest - on my new lift (the scooter one proved a little small for the triumph, and I wanted air-hydrailic anyway)
clutch - seems ok, but i have new friction plates ready to go in. Tangs on steels seem ok. Ordered new rod. The square ended studs were very lightly tack welded on. As the welds were small (and two of them broken off) I will clean them up and pretend they never happened. I made a cutch screw tool by welding a washer to an old screwdriver , then linishing half of it off. easy.
centrestand - my big chance to sort this out. Today I found the holes in the frame very elongated, the contact seats worn away, the spring bent and the whole stand bent. Still deciding what to do about all this. I 'unbent' the stand (I am a blacksmith of sorts). I will explore making bushes to go into the frame holes, and reface the contact seat on the stand itself. nything to avoid welding onto the frame.
Fuel tank - I should strip it back and sort it out, but I won't. No time.
Gearbox - Look, the thing changed through the gears alright, so I am going to reasswemble as-is. Welcome comments as to "while you are in there you really should...." One third of one tooth on one gear is chipped.
Carbs - have alredy sorted out a pair of very well refurbished carbs . 930 concentric Amals. hand made slides and remachined air screws.
Rocker boxes - will clean up a bit and replace o-ring. That's about it.

jimmy bush · 08-19-2009, 09:03 PM

I can see the picture of the engine on the stand and I'm only logged to truimphrat.net. Good progress. I need to start a thread for my 'in progress' street tracker.

delrazor · 08-22-2009, 07:40 AM

Sludge trap trapped sludge.
As I stated earlier, the sludge trap appeared to have never been opened, despite having had two top end rebuilds, a bottom end job all in maybe 100000 miles.
Well, the crank oilway was so restricted the bike was DEFINITELY on the verge of a stroke.

delrazor · 08-22-2009, 07:43 AM

My wife calls me lathey
I have to confess that I have had a lathe for 12 years and haven't used it... until yesterday.
My centrestand mounts were elongated by around 2mm, so I had to make bushes for them.
The first task was trying to ream out the holes. This proved difficult as access is impossible from either side. I welded a length of 8mm rod to a 9/16 drill bit, then tapered the bit at the blunt end up to the weld. I was able to then feed the drill bit backwards in the opposing hole then fit to the drill. Worked a treat.
Next I dusted off the old lathe and use a bit of logic. Drilled through the centre first, then put shaved a bit off at a time until it was 14.3mm. Used a parting tool to cut it off and bob's yer uncle.
Tapped in nicely. These were meant to be practice ones as I am not sure the correct internal diameter required. New bolts are on order as the old ones are all kinds of fifferent sizes depending on where you measure.

I also put some weld on the 'stopping point' of the stand then ground it back, replacing some worn material.