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Re: GT550 Cafe project

Posted: Fri Oct 07, 2011 2:11 pm
by tz375
I was looking at the side of the tank and you can see where it is tapering back to the rear and the new part is step out again. It's not a smooth transition. It might work with indents on the sides. I am not a fan of dents in tanks but it might be an "easy" way to get the sides looking good.

You're right about those early disks being less than amazing in the wet, but modern pads and drilled disk help a lot. Or fit an F3 disk and SV caliper. less weight and better brakes.

Those drums are popular in vintage racing. They are so heavy, I have had two of them and lightened them both and at the end of the day they were still so heavy that I sold them. With 2520 linings they can be made to work quite well. And you have already polished it so might as well use it.

Re: GT550 Cafe project

Posted: Sat Oct 08, 2011 8:21 am
by Coyote
More inspiration? The only changes I made since this photo is new tires, a slotted rear rotor and 1" rise handlebars.

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Re: GT550 Cafe project

Posted: Sat Oct 08, 2011 12:55 pm
by two-stroke-brit
that is the most appealing to the eye cafe of any old stroker that i have seen, let alone a gt550,
nice work coyote

Re: GT550 Cafe project

Posted: Wed Oct 12, 2011 8:53 pm
by Joiseygirl
@ Coyote - Love it, it's beautiful!

Re: GT550 Cafe project

Posted: Thu Oct 13, 2011 12:40 am
by TLRam1
What kind of tires are those Chris?

Re: GT550 Cafe project

Posted: Thu Oct 13, 2011 11:19 am
by Coyote
The tires that were on in the pic are Dunlop Vintage Bias K70 and K81. They can be had here: http://www.tiresunlimited.com/default.htm" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; The tires were old and hard so I replaced them with some Kendas. Surprisingly good tire for the money and they are stickier than my Bridgestone Spitfires on my GS1000. I bought them from the outfit I linked to.

Tank work, some more polishing...

Posted: Sun Oct 23, 2011 5:34 pm
by imquattro
Well, this past week or so I've been putzing around with the tank.
My goal was to give it a stretched look, to tuck some wiring up under it, and to fill the gap left when the seat's moved back.
So, here it is in it's final shape (still being smoothed).
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Here you can see how it's been done:
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I went with knee dents because I liked the look.
I'm still deciding upon paint schemes, but I'm leaning toward a silver tank & tail w/ a large black stripe (width of raised center hump) with two smaller (1/8" wide -one on each side) paralleling it.
And the frame gloss black -or silver.... idk....
Here's a before and after polish job:
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More to come.

Head work, cylinder work, spoke work...

Posted: Tue Oct 25, 2011 7:30 pm
by imquattro
After verifying the donor engine is sound, we pulled the head & cylinders off for cleaning & port smoothing.
Here's a quick comparison between a '72's cylinder & a '74's cylinder.
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You quickly can see a size difference. ('72 on left, '74 on right.)
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Also noted are the increased cooling fin size, lower intake & exhaust ports, and what looks to be larger intake ports.
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Here's post cleaning:
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(Previous Owner (po) stripped out an exhaust bolt hole & used a stud in another -all fixed now. :up: )

So, lets talk spokes. In the initial pictures of the bike(s) the spoke were/are pretty nasty. Corroded, rusted, some bent... my plan was to replace them.
Well, at $80 a set for new chrome or stainless, I was penny pinching.
So I looked into getting the old ones replated.
Daisy-chain called 4 places only to be told A) they no longer did it due to EPA restrictions, or B)due to the time involved, they charge $20 a spoke, and $300 a rim.
:wth: :shock:
Um, ok, so that would be $20 x 72 spokes + $300 x 2 rims = $2040+shipping & tax? :shock:
SOO! :arrow: how bout them spokes from Hong Kong?
or better yet, lets see what I can do w/ the ones I have here for free....
Well, I didn't want to paint them or powdercoat them so I scotchbrite padded them then buffed them.
Here's a before and after:
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The finished ones still need hand polished (wiped with a rag as they have compound still on them -the dark spots).
BUT I think I can live w/ those. :up:
Only takes 2.5 minutes a spoke start to finish (x72).... but its free! Now...what to do with the nipples....?
They're too small to run on the buffer.... I need to think more about them...

When I removed the head, I found the Right cylinder (headgasket) had started to leak. So I checked straightness w/ my straightedge and found .003" warp from LEFT to RIGHT, w/ the center being the low spot.
Since I'm cheap but resourceful, I tossed down my tempered glass, attached some 700 grit wet/dry paper to it, sprayed it w/ WD40 and lapped the head flat (or quite close to it). Warp was lowered to less than .001" LEFT to RIGHT.
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I then polished the combustion dome for each. Below are before & after. Not going for a mirror finish, but something better than factory.
RIGHT:
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CENTER:
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LEFT:
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Here's the head after:
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More to come... (case breaking/cleaning/painting, piston cleaning/polishing etc....)

Re: GT550 Cafe project

Posted: Tue Oct 25, 2011 8:30 pm
by tz375
Spokes cleaned up nicely but the plating is no all buffed/scoured off and they will rust fast. Are you planning to paint them or re-plate them. Phone around and ask for bright zinc plating. We have had dozens of sets of spokes re-plated in zinc and then baked to reduce hydrocarbon embrittlement. It's not usually too expensive. We get all teh spokes and other hardware plated in batches and it's around 300 for all the batches including baking.

Why does that 74 barrel say348cc on it? Is that from a GT380 motor? For some reason I though you had a 550. I don't know much about the smaller triples, but it could explain the differences between one motor and the other.

Re: GT550 Cafe project

Posted: Wed Oct 26, 2011 5:20 am
by imquattro
tz375 wrote:Spokes cleaned up nicely but the plating is no all buffed/scoured off and they will rust fast. Are you planning to paint them or re-plate them...
Why not clear coat them? (Free, remember, if you've been following this thread, I'm on a wife pleasing budget -aka "can't spend anything")
Why does that 74 barrel say348cc on it? Is that from a GT380 motor? For some reason I though you had a 550.
Had me freaking out about this one...
Looked again this morning... says: 543CC on the barrel, not 348CC.

Re: GT550 Cafe project

Posted: Wed Oct 26, 2011 8:28 am
by tz375
No way. It looks just like 348. How funny is that?

I understand the zero budget concept all too well. You could try clear coat but I suspect it may not last as well as plating or new spokes.

Re: GT550 Cafe project

Posted: Thu Oct 27, 2011 8:46 am
by Suzukidave
Could you take a picture down the cylinder as it would be interesting if the one set is the chrome bore ones with the different porting .

Re: GT550 Cafe project

Posted: Thu Oct 27, 2011 8:51 am
by Suzukidave
For a low cost setup to plate the spokes you might look into a DIY zinc plating http://www.ehow.com/how_7886110_diy-zin ... icals.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; this could also be used to redo other nuts n bolts that might look grubby on the bike .

Case carefully disassembled and cleaned.

Posted: Mon Oct 31, 2011 7:08 pm
by imquattro
Before:

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Video of case after opening: https://picasaweb.google.com/lh/photo/K ... directlink

Video of case after crank & gears are removed: https://lh3.googleusercontent.com/-dKvD ... _00027.jpg

I found 2 of the three SRIS check valves stuck closed and one stuck open.
They are easily pulled apart, cleaned, and reassembled. Working perfectly now.
1 screen was mashed, 2 were intact but holed.
All were removed. The '72 didn't have them at all.

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After glass beading (bottom of case pictured only. Top was done too, but not pictured):

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Re: GT550 Cafe project

Posted: Mon Oct 31, 2011 8:48 pm
by TLRam1
Never ceases to amaze me the difference after media blasting, makes them look new again. Great feeling starting out with something clean and new looking to go back together with.