Topic: Phaedrus: CB750 RestoMod - Update: 09/23/21 w/ new video

[goon 1492]

looks like your on the right track, if they have an abs glue that is cheaper go for it. MEK might be a "hotter" chemical than the actual glue because it will literally melt it into a pile of goo if you use too much. I am not sure what the rear fender is made of, I would think abs but thats just a guess.
Maybe find an inconspicious area and a q-tip and rub a bit on and see what happens. Wish I could help more there.

[MCRider]

looks like your on the right track, if they have an abs glue that is cheaper go for it. MEK might be a "hotter" chemical than the actual glue because it will literally melt it into a pile of goo if you use too much. I am not sure what the rear fender is made of, I would think abs but thats just a guess.
Maybe find an inconspicious area and a q-tip and rub a bit on and see what happens. Wish I could help more there.

That all sounds good. Wish I'd kept my original inner fender to practice on, but it was in worse shape than this one and I tossed it. But I'll be buying both PVS cement (I have a plumbing job to do) and ABS cement and I'll test each on lower inner edge of fender and report back.

The MEK with your applicator or KGhosts goo approach is still probably the best.

Oh yeah, what about the ABS question, do you actually feed ABS scrap into the weld? KGhost says he makes a goo out of the MEK and ABS shavings. I don't have any handy.

[HavocTurbo]

I don't know what year but there was one on ebay last night for about $5 shipped. IIRC it was for a SOHC.

[MCRider]

I don't know what year but there was one on ebay last night for about $5 shipped. IIRC it was for a SOHC.

I know, I got this one for free from a forum member, and I was perfectly fine with the crack. But now that I'm ready to use it, I'm obssessing over the crack as I'm wont to do. So I'll give fixing it a try and if not, I'll look for another one witout a crack. They are out there.

THis one is real good otherwise, and others may have problems elsewhere. I was surprised when I un-mounted the original inner fender how broken and wollowed out it was.

[HavocTurbo]

Oh hell I meant to practice on. 

I'm pretty sure I threw mine away. I'll look for it though.

[goon 1492]

Yeah and if ya need I can ship ya a piece of 3mm black abs, that's as thin as I can get. Pm me if ya need it.

[MCRider]

Yeah and if ya need I can ship ya a piece of 3mm black abs, that's as thin as I can get. Pm me if ya need it.

Yes, I'd like to have that in my kit. I'll PM you. Don't expect I'd need much, whatever would fit in a first class envelope, if you have such a scrap.

I did my first test last night with the ABS cement from Lowe's. Looks promising. My crack actually had some daylight showing through. The cement seems to have filled that in by melting the 2 edges together. Its still clamped and I don't want to stress it yet.

If i get a repair that will stand up to the flexing involved in installation, once its installed there won't be much more to withstand. It appears that the inner fender can only be installed and removed properly by removing the swingarm first. If someone were to attempt to remove the inner fender with the swingarm in place, which is very tempting, they would have to squeeze it to get it out of the tangs on the frame that hold it and that would precipitate the cracking.

With the swingarm gone, I need to remove it one more time anyway, the inner fender should slide easily into place.

I have many pictures for my next update.

[HavocTurbo]

I sit here anxiously waiting your update.

I looked for a couple of hours for my inner but to no avail. They come out (on the K8 anyway) easy as pie without the swingarm. Hopefully installation is just as easy.

[MCRider]

I sit here anxiously waiting your update.

I looked for a couple of hours for my inner but to no avail. They come out (on the K8 anyway) easy as pie without the swingarm. Hopefully installation is just as easy.

Pictures won't be necessary. The experiment was a qualified flop. Where with the airplane glue, the "weld" snapped when stressed, the ABS cement was a little mushy, but it gave it up with little effort. Unacceptable. No shortcuts if a true "welded" joint is what one wants.  So it looks like the Goon and KGhost approach, using MEK or a slurry of MEK and ABS shavings, is the next step. I won't be able to try that before returning home from the California trip.

So I may give the ABS cement one more shot, gluing the full length of the wound and letting it sit for a week. For this repair that may be enough. But if it required real strength and resistance to further cracking through vibration (like a sidecover) MEK is probably the key.

I have plenty of other things to do to the project this weekend.

[mystic_1]

V-groove the crack on both sides before you attempt your next repair.

Cross section:  ========x=======


mystic_1

[MCRider]

V-groove the crack on both sides before you attempt your next repair.

Cross section:  ========x=======


mystic_1

OK, but I do think the proper chemical is the key. it needs to melt the plastic.

[MCRider]

And so, I tried the PVC cement just to rule out everything. On a scale of 1 to 10, for crack repair, airplane glue is 0, ABS and PVC cement are 1s. I'm looking for at least an 8.

Just so you'll have something to rest your eyes on, here's my sidecover that was professionally "welded" back in 2000:

The note was written by myself to the welder. If you Google "plastic welding" you'll find many outfits that can repair this stuff like new and paintable.

Here's the painted side, the crack started at the left edge of the indent for the emblem, and continued to the left edge of the cover. If you hold it in the light just right you can see the shadow of the repair, essentially unseeable. What looks like a crack in the picture is actually much higher up and is light glare. The paint is very reflective.


while they are unwrapped, here's what it'll look like on the frame. Should be sharp with the emblems in place.

For nostalgia buffs I keep them wrapped up inside this antique bell helmet bag, with the famous bell poster. Who can remember when the dividing line between sub-prime and prime helmets was $10?


Well, if I gert my chores done I'll run to the hardware and get some MEK. I'm obssessing now and want to see if i can fix this myself.

[DollarBill]

My identical Bell helmet bag holds a heavy duty fishing inner tube these days.  I love that bag though!  The purple side covers look great!  Didn't Prince use a SOHC4 in his Purple Rain movie?

[MCRider]

My identical Bell helmet bag holds a heavy duty fishing inner tube these days.  I love that bag though!  The purple side covers look great!  Didn't Prince use a SOHC4 in his Purple Rain movie?

Good use for that old bag. I'll die with mine, but the new materials are so much better.

Here's the Purple Rain answer. I could have done without someone dragging up that reference though. 

http://au.answers.yahoo.com/question/index?qid=20070326220727AAusPvn

[MCRider]

I'll have an update with pictures soon. But I want to say before I forget again.

1. Never paint the tins first, always last. I painted first, and while I'll use them to get going, its not the end game paint job. The purple is good, but the pin stripes color don't make it. And some work on the tank will probably ruin the paint.

2. After all the time I spent, chipping off bird sh-t welds and smoothing, now with the finish powder on I see lots I missed. Should have chipped, glass beaded, brought it home, chipped some more, then went for the coating.

[MCRider]

It was a beautiful day to be a live and living in central IN. Blue skies, bright sun, low humid, breeze.

Got more progress done. Obssessing over this crack in the inner fender. Probably could have had a new one for the time and effort i've got in this. Butt don't mind having some used parts especially if I learned how to fix them in the process. Something old, something new, etc... So I bought some MEK, got some glass eye droppers from CVS, and went to work. Laid out a stream, clamped it, set for 15 minutes, repeat. Assume 24 hours total set up, but it looks promising.


Then got to work on VIN plate. I actually mangled it pretty good getting it off. It is very thin and was glued besides the rivets.



It was actually worse, had already straightened it a bit. The scuffing in the middle was from prior street duty, a cable was rubbing on it for some time.  So beside using some Goof Off to get the adhesive off, we laid it on a 2" piece of PVC and tapped on it with plastic hammer to flatten and restore the curve. Then reduced the tube to 1 3/4 then 1 1/2 so the curve is less than the curve of the steering head. When it goes back on the edges should lay flat to the frame.




Good result. The rivets I have are slightly larger than the holes in the plate. I'll go to my step dad, he has a hobby size drill press, just the thing to carefully enlarge these.

Got  some 8mm threaded rod and made the ""bolts" for the top tree clamps. Per Ecosse's suggestion. Came out good. (I know the spacers for the tube clamps are missing. They're in a box/bag somewhere, I'll come across them before cranking those clamps down.)





Froze the steering races and got the triples mocked up.


Don't know if I'll use the tweak bar, but I had it made years ago by a machinist and its a beauty. Most storebought tweaks only clamp inboard of the tubes, OK but sure not the best. This tweak  the 2 halves are pinned for accuracy, the internal clamps bring it down to a slight friction. The outboard clamps down hard. My tubes are 2" over to restore ride height from the 17" front wheel, thus my thought to run the tweak.

The tubes have a "FORKING BY FRANK" lettering in them, ghosted in the chrome in appears. Probably a decal, but you can't feel it with a fingernail.



View from rear.

Gotta try to get something done each night this week as I'll be gone for 7 days come 7-2.

[HavocTurbo]

What did you coat the ends of your frame cut-outs with? Looks cool but I cannot tell of they are bare or?

Looks awesome!!

[MCRider]

What did you coat the ends of your frame cut-outs with? Looks cool but I cannot tell of they are bare or?

Looks awesome!!

The powdercoaters glassbeaded the whole thing. I don't know if they treat it with anything at that point or not. They masked those areas, and as far as I know they are not coated with anything, just the frame post bead blasting color. I'll probably wipe it with a rust preventative like phosphoric acid which leaves a rust protectant coat without any thickness.

I'm using an APE style (discontinued) frame rail kit. I've had it since 1980 and used it on this bike from then till when i parked it in 1995. Never any noticable weakness, etc. The way it works, there can be no extra thickness there. When I get to that point it will be more clear.

Gordon's kit would not have this limitation.

[HavocTurbo]

I was thinking a good coat of 30w ought to keep things pretty shiny. Does the acid trick leave any film or anything?

[MCRider]

Looks great, really like the polished tripple clamps. Will those acorn nuts clear the gauge clamps?

Shouldn't be a problem, I'm using K1 gauges which have pretty inocuous clamps. But even if K2+ I can't see a problem. Easy to switch back if I need to.

The acorns are a little 70s disco but I don't mind tweaking the styling theme hear and there.  

[MCRider]

I was thinking a good coat of 30w ought to keep things pretty shiny. Does the acid trick leave any film or anything?

Its acid about as strong as 4x PepsiCola. Leaves zinc phosphate coating. There is no film or anything detectable, just treated steel.  This is the product i have, but there are plenty.
http://www.eastwood.com/catalog/product/view/id/2448/s/ew-fast-etch-16-fluid-oz/category/26/

[MCRider]

Looks great, really like the polished tripple clamps. Will those acorn nuts clear the gauge clamps?

Looking at that picture, i can see why you'd ask. I think they are on different planes, but I'll need to check.

[mystic_1]

Got  some 8mm threaded rod and made the ""bolts" for the top tree clamps.

There you go!  

Do believe I was the one who suggested the double-acorn thing.  Glue one of the acorns to the threaded rod with superglue, JB-Weld, red locktite, or whatever, that'll make handling them easier.

As many bolts as possible on my project are being replaced with either acorns or stainless allens.

mystic_1

[Shenanigans]

I just want to say that this kind of level of attention to detail is how I think ALL personalized bikes should be treated to. Excellent work!

[MCRider]

Got  some 8mm threaded rod and made the ""bolts" for the top tree clamps.
snip

There you go!  

Do believe I was the one who suggested the double-acorn thing.  Glue one of the acorns to the threaded rod with superglue, JB-Weld, red locktite, or whatever, that'll make handling them easier.

As many bolts as possible on my project are being replaced with either acorns or stainless allens.

mystic_1

Oops, mea culpa!  Thank you Mystic for the idea!  Yes I'll be gluing one of the acorns into place to act as a "bolt".