My project '91 ST: A UJM for the 90's

Today I had a short day due to a morning meeting. I refinished the three calipers (honed and repainted with some red caliper paint). I think I lunched the pistons taking them out, so I'm definitely going to have more in the brakes than the bike cost. I went through the exhaust clamps with a tap to clean the threads and painted them with high temp aluminum paint. Last night I ordered a bunch of OEM parts to include carb & caliper seal kits and other wear items. I've also ordered some used stuff off eBay such as the left side cover, a horn, and both bar switches and a new set of decals for the shelter.

I've also got a 45L trunk on the way and a 12x10 aluminum plate to mount it. I shot some pics today and will update here later. The last stuff I ordered were some metric socket bolts to replace some of the hex bolts on the bike. With a few days of tolerable weather and some more stuff I can make some good headway. I've also tentatively decided on gloss white for the fender, shelter, side covers, and tail section with gloss black for the fairing, trunk, and wheels. I have two vehicles from the 90's with this paint scheme, so it will fit right in and allow for some distinction.

EDIT
Pics:
Brake calipers


Gas tank removed


Muffler clamps


Spare wheel


Exhaust pipes


LED bulbs

Fast progress!

Keep us poSTed.

Well, I'm frustrated by the high cost of parts (again). Looks like caliper pistons are anywhere from $22 to $26 each. The size is 27mm diameter x 31mm deep, which is something of an oddball. I found a company called K&L Products that sells 27x25 and 27x35 pistons for a good bit less (like $15 for the 35mm ones with $5 flat rate shipping here). Apparently they used to make the 27x31 pistons, since I found a part number (32-2305) for that size. The only place that sold this was as high as OEM, so no benefit there. I'm thinking the trick may be to buy a set of the 35mm pistons (32-4187) and cut them down to 31mm. The 35mm pistons were used on several bikes, notably the 81-82 CBX rear brakes. I tested this theory on one of my old pistons with a 10" cut off saw and it came out a little short, so I'd have to allow for more blade width when I cut.

I played around with some machine shop software and found I could make these pistons out of 304 stainless steel in a run of 100 for under $10 each. Aluminum would be a little less. Seems like there would be some money to be made if someone wanted to invest in a project like this. I also made a generic steel rotor with 6 mounting holes and a bunch of cross-drilled holes and got a unit price of $120 for a run of 25.

I've not heard back from the guy about the Galfer rotors, so I'm thinking that was not to be. I'll have to scout out some decent used rotors.

Other than that, my new mirrors arrived today. They have LED lights built in the back, so they will function as auxiliary turn signals:

If your problem is with the length of the pistons you can send them to me and I can turn them down for you. All you would have other than new price would be shipping. No problem to do it, glad to help if I can.

I'll keep that in mind. I'm looking at saving about $7/piston, so this is $42 gross for 6 pistons. I'm still interested in making my own. I'll post this idea elsewhere and see if there is any market for stuff like this.

I can't wait to see this one finished!!!

I've been learning & playing around with the parts design software. I made a generic 290mm diameter brake rotor with 6 larger mounting holes and 102 small vent holes (the OEM has 50, I'm still learning sizing & spacing). I also drew the brake piston. I'll attach the graphic files. The rotor made out of cast iron for a run of 25 costs less than $80/unit.

There has got to be a better way to get brake rotors for these bikes. If this works out I may be on to something.

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48 hole rotor attached, I'm getting the hang of the software.

Re the pistons. The OEMs are anodized for wear resistance. I bet using a SS would be good as well. It would be a fun project to try. I would think the only real important thing would be the tolerance allowed. Maybe some one has some new ones that they could measure. I would need the sizes to be taken with a tenth mic that is calibrated. Or if I could have some sent to me I would cover the return postage.

The '91 shop manual has some specs for the pistons- the OD minimum is 26.918 and the maximum 26.968 (or 1.0598 ~ 1.0617 inches). I got 26.91~26.93 diameter and 30.88~31.04 length on my digital caliper when I measured the best one I had. The service limit is 26.91.

Using the software, anodizing the 6061 T6 aluminum keeps the cost under $12 per 100. The 303 SS are under $8. The minimum linear tolerance figure available is +/- .12mm, so this could return a diameter of 26.848, which is below spec.

I updated the above post with a 48 hole rotor, which looks a lot better than my first attempt.

Back on topic, the Magnaflow mufflers arrived today. I'll have to blast & paint them as there is some surface rust around the seams. Should be a good fit though for $57 and change each with shipping.

I also pulled the oil pressure sender so I can see about plumbing in senders for the combo oil pressure/temperature gauge I'll be installing. Looks like a tight fit under the black box on the right side, but I mocked up some 1/8" pipe and it looks like the senders can fit outside the frame and under the side cover. The OEM sender looks to be 1/8 British pipe thread.

Okay, I will try to turn one up next week and see how it goes. I'm not trying to horn in on your possible venture, only trying to get some for this project for you. can't wait to see it done. Have you had any luck with a Vetter yet?

SHP, diameter is the obvious important measurement on the pistons. Slightly short shouldn't be a problem, just won't be able to use ALL the pad thickness.

The disc rotors look good, I'd take a pair if the project comes together.

BTW, I've never bothered to change out any of the brake pistons, even with slight scoring. Never a problem. New seals seem to hold up just fine with used pistons.

I was wondering how bad they were too George. Maybe they will be fine. How bout some pics ST_SHP?

Bigmak96 said:

Okay, I will try to turn one up next week and see how it goes. I'm not trying to horn in on your possible venture, only trying to get some for this project for you. can't wait to see it done. Have you had any luck with a Vetter yet?

Click to expand...

No problem, I don't have the capital to invest in this project right now anyway. I ordered the $15 CBX pistons and will cut them to size.

I used the RAN list for a fairing I found in Wichita KS for $25. Looks like it has the tall windshield also. One of our members there put in a call to the seller and is waiting for a call back (the saga of Craigslist continues, maybe it's me, but if I advertise something I return calls & emails to sell it). There is also one in South Carolina the seller is supposed to be sending me pics for. I've posted this on three sites, I think it was here one of the members offered a radio housing. I've ordered some digital gauges on eBay (voltmeter & thermometer) and will be getting a combo oil pressure/temperature gauge to go into the housing.

Here's a pic of the one on my GS1000:


The Equus gauges I used were over 20 years old! I had them leftover from another project. I'm going to replace them with digital units since it's hard to read them at times while riding & the air temperature gauge tends to bounce around. If I like what I'm putting on the ST, I'll do that again for the GS.

I have the combo digital gauge & voltmeter on my Concours. Here's what they look like:

Bigmak96 said:

I was wondering how bad they were too George. Maybe they will be fine. How bout some pics ST_SHP?

Click to expand...

I'm not sure how well this came out:


The third one from the left is the one I cut down. The remainder have tool gouges near the top. I probably could use them, but it's one of those repairs I don't want to do twice. I noted the right rotor was worn uneven from the left, I'm sure uneven pad pressure played a part in the problem.

Those are pretty nasty. You are prolly on the right track to replace them. I sure would. I was thinking they had minor lines in them. I will try to spin one up next week and let you know how it goes.

I took off the wheels today. As John McLaughlin would say, here's the next issue:


Didn't notice it until I had the wheel off. Looks like another part to be added to the used parts list.

Here's a shot of the Magnaflow mufflers laid out with the existing pipes:


The mounting clamps are too big, so I'll have to shim them.

I'm also measuring for braided brake lines for the front (MIA) & clutch. The rear hoses look to be OK. After pulling a front rotor, I see where more machining would be needed for the seats for the bolts. Definitely best to just stick with some used parts there for now.

What kind of Vetter are you looking for? I might know of one in central SC, but I'll have to check to see if he still has it.

A Windjammer IV or V, the one with the integrated turn signals. Need a radio box also to mount gauges. There was one FS on eBay recently in Columbia, SC- maybe the same one?

I removed one front rotor today & measured all the dimensions. Attached is a revised 315mm rotor drawing. I made 6 large round holes to remove weight vs. the numerous 4-sided cutouts on the stock rotor. The picture angle is a little different so you can see the countersunk holes. Even with the extra work to countersink the mounting holes it's still <$90 in a run of 25.

SHP, here's a link to a rim repair shop, been used by a couple folks on the liST. I have a front that's about the same as yours, gonna ship it to him.

http://willsrimrepair.com

Got this from Kevin in Wisconsin who got it from Tim at Two Brothers Tires, whom I trust explicitly. Kevin, not so much rofl1 (Jus' kidding, Keving. )

Thanks for the link. The other place members were talking about was $80+ shipping & in Colorado. This place is closer & less costly, plus recommended. I like their front page also:
Thank you for your interest in Wills Rim Repair!

* Bent rim got you bummed?

* Did you catch a hidden pothole and now your rim won?t hold air?

* Come down too hard from a wheelie and cracked your wheel?

No Problem! Wills Rim Repair can help!

EDIT
Another post, another attachment. This machine shop software is more addictive than a video game. I've almost gotten the OEM pattern of 50 x 8mm holes. This one has 60 but looks decent.

What is the I.D. of the pistons?
Also I am wondering if the extra weight of the SS will effect the retraction any. I'm thinking not but I'm not sure???