Time to sort these out.

[Speed Reycer]

Hey Everyone. I have really enjoyed browsing around this website. To be honest I started visiting and browsing, on and off for awhile.

I am from Seattle. Scattered Honda mini bike enthusiast where I live, not many get togethers (at least that I am aware of) so having a site like this has been a great wealth of information, very appreciative of that.

A couple of unrestored bike I have had in my garage for awhile. Time to get both sorted. Like many, a childhood dream realized.

I picked up the ST90 in 2012, Washington titled bike. I had the ST90 running a few years back and currently in the process of adding the complete rear turn signal light assemblies, just ordered and waiting for screws for mounting as well as a few bits here and there... Shows a bit over 1400 miles on the odo. Maybe some trained eyes on this site can qualify parts that may not be correct.

The 74 CT70 K3 is another bike purchased from a fishing and Honda motorcycle shop in Seattle. I have know about since CT 70 since 74 it was a friends bike. I believe this to be complete and original. Showing 208 miles on the odo. Sat in my garage for the past 6 years and no idea how long prior elswhere. Did an initial cleaning of all the dust, sawdust, and road grim. Really surprised how like new it is. hmmm maybe cuz of the mileage lol. The seat shows the worst. He had cats and the way the rips look is like cats using the seat as a scratching pad.. Just a guess. I want to replace the cover. Found one on DrATV. Is this a good source? I also found a source for the CT70 Specific Battery with the fused and connector terminals. It appears the original harness is still in tact and not cut up. Tools bag is also there. Loving this CT!!

Batteries, carb cleaning, and plugs is where I will start.

I really want both these bikes to be OEM if possible and believe great candidates to live on as unrestored bike. Love your opinions here.

Sorry for the long post... just absolutely inspired and excited!!

 

[cjpayne]

Nice find, especially the mint '74CT70. Guard those headlight ears!!! They are nearly impossible to replace and are VERY expensive if you can find mint originals. Unless your street driving it all the time, remove the blinkers. Check the air filter element. It may be crusty/crumbly and need replaced.

 

[kirrbby]

Some pretty fantastic lookin bikes you have there Speed Reycer!
I'm not very familiar with the ST90's. The headlight ears on that bike catch my eye. I'm not sure if they are correct parts, or aftermarket parts.

The CT70 is near pristine. I thought you had it all shined up nicely, but then I seen, it's actually still dusty dirty. It's missing the rubber ring that goes on the speedometer...that's all I noticed. That bike is a good candidate for...anything. Put it on the shelf...under glass...show bike nice. Or ride it and love it. Awesome bike, and a awesome K3 is pretty hard to find.

As nice as it is, and with only 200 miles on the clock, don't be surprised to find the exhaust rusted nearly thru, under the clamp for the big heat shield.

Is the gas tank clean inside?


Welcome to lilHonda!

 

[Speed Reycer]

Nice find, especially the mint '74CT70. Guard those headlight ears!!! They are nearly impossible to replace and are VERY expensive if you can find mint originals. Unless your street driving it all the time, remove the blinkers. Check the air filter element. It may be crusty/crumbly and need replaced.

Since I am half way retired I checked... The filter basically crumbled in my hands. On my list of parts... thanks

 

[Speed Reycer]

Some pretty fantastic lookin bikes you have there Speed Reycer!
I'm not very familiar with the ST90's. The headlight ears on that bike catch my eye. I'm not sure if they are correct parts, or aftermarket parts.

The CT70 is near pristine. I thought you had it all shined up nicely, but then I seen, it's actually still dusty dirty. It's missing the rubber ring that goes on the speedometer...that's all I noticed. That bike is a good candidate for...anything. Put it on the shelf...under glass...show bike nice. Or ride it and love it. Awesome bike, and a awesome K3 is pretty hard to find.

As nice as it is, and with only 200 miles on the clock, don't be surprised to find the exhaust rusted nearly thru, under the clamp for the big heat shield.

Is the gas tank clean inside?


Welcome to lilHonda!

Thanks for the welcome! I am having a blast learning about this bike. I

am not sure how to check if the Headlight ears are correct. It appears looking around the bike a lot of the bolts and screw head have never seen a screwdriver or wrench.

I did however remove the front exhaust guard carefully to expose what you might be talking about... Curious if the back bracket and (fiberglass?) insulation are separate pieces from the pipe itself? I didn't want to try and force it off... A fair bit of corossion is present and fused this bracket to the pipe I think. Options of cleanup and prevention?

I also took a pic of the inside of the tank and some of the gas that was in it... There was under a pint in the tank. At least 6 years old if not more.

Also I found the rubber ring... Slipped off but found it hanging loose under the gauge. Does this fit over the top ring?

Thanks again.

 

[69ST]

No great surprise, or loss, with that crunchy foam air filter element. After 45 years, it doesn't owe you anything. The seat cover is available and, this model has the later composition foam which, unlike latex, doesn't turn into Graham Cracker crumbs.

Beyond those items, I only see minor cosmetic things that should be very easily freshened. If the chrome is as rust & pit-free as it appears in these pix, then a little wax ought to make it sparkle. The polished aluminum bits will likely return to their full glory with a good rubdown & Shiatsu, using aluminum polish, a soft cotton rag and some elbow grease. The scratched heatshield inset, on the muffler can be repainted. Scuff the existing paint, mask the shiny parts, give it a chemical wipedown and respray it.

One last item, the oil spinner. Mileage-wise, it's still a little early for its first cleaning. However, this engine has spent most of the past 5 decades sitting, presumably with oil oxidizing inside the crankcase. Thus, I'd want to clean it and check for light sludge in the bottom of the crankcase. If you find any, some Brakleen will get most, if not all, of it quite easily, while you have the clutch cover removed. Assuming that the engine still has full compression, that'll allow it to pick up where it left off, presumably circa 1974 without hibernation sickness. There is a distinct possibility that the engine sat, for all those years, with one valve open which can allow moisture inside the top end...with rust forming as a result.

 

[kirrbby]

That is the rubber trim I was talking about. It fits over the chrome trim around the top of the speedo. It might be tough to pull it back up and into place without tearing it. Usually it's installed from the top.

And, that is the spot on the exhaust too. That stuff they use as packing, or as a insulator, causes the pipe to rot...quickly. you should be able to peel it off...there is a split in it somewhere. If the pipe is still solid, just clean it up and paint it. The replace the packing with some header wrap. Or, put a piece of stainless shim stock under it to keep the packing material from touching the steel pipe.

The danger is that the pipe might be rotten to the point of fragile, and will break in two when you try to remove it from the bike. Then you have to start with a weld repair, and you'll have to get the pieces lined back up straight, and at the correct length. Probably best to peel the packing first, before you remove the pipe. See what you're up against.

 

[kirrbby]

BTW, the packing/bushing, whatever you call it, is still available new from Honda. So if you break it etc, no biggie.

 

[cjpayne]

There is a thread I wrote in the Tech Area of this forum to guide you through the spinner/filter cleaning that racerx was talking about.

 

[Speed Reycer]

No great surprise, or loss, with that crunchy foam air filter element. After 45 years, it doesn't owe you anything. The seat cover is available and, this model has the later composition foam which, unlike latex, doesn't turn into Graham Cracker crumbs.

Beyond those items, I only see minor cosmetic things that should be very easily freshened. If the chrome is as rust & pit-free as it appears in these pix, then a little wax ought to make it sparkle. The polished aluminum bits will likely return to their full glory with a good rubdown & Shiatsu, using aluminum polish, a soft cotton rag and some elbow grease. The scratched heatshield inset, on the muffler can be repainted. Scuff the existing paint, mask the shiny parts, give it a chemical wipedown and respray it.

One last item, the oil spinner. Mileage-wise, it's still a little early for its first cleaning. However, this engine has spent most of the past 5 decades sitting, presumably with oil oxidizing inside the crankcase. Thus, I'd want to clean it and check for light sludge in the bottom of the crankcase. If you find any, some Brakleen will get most, if not all, of it quite easily, while you have the clutch cover removed. Assuming that the engine still has full compression, that'll allow it to pick up where it left off, presumably circa 1974 without hibernation sickness. There is a distinct possibility that the engine sat, for all those years, with one valve open which can allow moisture inside the top end...with rust forming as a result.

Got it... Thanks... If feels like there is good compression. Will look at the oil quality

 

[OLD CT]

Buy a ''sealed'' battery not a acid filled leaker. The acid filled style battery has a shelf life of around a year if you are lucky.

 

[69ST]

Sounds like you're in good shape, engine-wise. Wouldn't be the first time someone has gotten a bike in which the engine sat with both valves closed, for sure. FYI, those are the ones that come out of suspended animation, exactly as they went in, none the worse for the experience.

Do yourself a huge favor and service the oil spinner sooner, rather than later. It's due at the 300-mile mark anyway. The difference between one of these motors that's in desperate need of a rebuild with 2K miles, or less, on the clock and one that's still strong with 5 times that mileage is largely how clean the oil was kept. And run a JASO-spec, wet-clutch-compatible motorcycle oil. Automotive oil will contaminate the clutch fibers, resulting in a slipping clutch...and...the lack of zinc is brutal on shift forks. A lot has changed since 1974, including oil & pump gas. Judging by the inside of the fuel tank, which should be cleaned, the crankcase most likely has some nastiness that you really don't want circulating throughout the engine.

The tank can be cleaned using acetone. That should cut all of petroleum residue. If it's rusty, follow that with phosphoric acid, or Evaporust. Pull the tank out of the frame, first, to prevent tragedy. It'd be a good idea to replace the fuel lines at this time, too. 2018 pump gas is murder on neoprene rubber fuel hose.

 

[OLD CT]

Here is a good one for $10.99 shipped from N.Y.C. on ebay. You cut the old wiring as close as you can on the original old leaker and add crimp on terminal ends, for the new batt..

 

[Speed Reycer]

Here is a good one for $10.99 shipped from N.Y.C. on ebay. You cut the old wiring as close as you can on the original old leaker and add crimp on terminal ends, for the new batt..

Great Thanks for the link. Was considering sealed... Just need to figure out the connection to the existing harness without cutting it apart

 

[Speed Reycer]

That is the rubber trim I was talking about. It fits over the chrome trim around the top of the speedo. It might be tough to pull it back up and into place without tearing it. Usually it's installed from the top.

And, that is the spot on the exhaust too. That stuff they use as packing, or as a insulator, causes the pipe to rot...quickly. you should be able to peel it off...there is a split in it somewhere. If the pipe is still solid, just clean it up and paint it. The replace the packing with some header wrap. Or, put a piece of stainless shim stock under it to keep the packing material from touching the steel pipe.

The danger is that the pipe might be rotten to the point of fragile, and will break in two when you try to remove it from the bike. Then you have to start with a weld repair, and you'll have to get the pieces lined back up straight, and at the correct length. Probably best to peel the packing first, before you remove the pipe. See what you're up against.

got it off.. used Aerokroil and a bit of patience. Pipe feels solid, pitted though... Soaking the bracket in evaporust... I know its overkill but considering ceramic coating black... Great success with other motorcycles.

 

[Speed Reycer]

Sounds like you're in good shape, engine-wise. Wouldn't be the first time someone has gotten a bike in which the engine sat with both valves closed, for sure. FYI, those are the ones that come out of suspended animation, exactly as they went in, none the worse for the experience.

Do yourself a huge favor and service the oil spinner sooner, rather than later. It's due at the 300-mile mark anyway. The difference between one of these motors that's in desperate need of a rebuild with 2K miles, or less, on the clock and one that's still strong with 5 times that mileage is largely how clean the oil was kept. And run a JASO-spec, wet-clutch-compatible motorcycle oil. Automotive oil will contaminate the clutch fibers, resulting in a slipping clutch...and...the lack of zinc is brutal on shift forks. A lot has changed since 1974, including oil & pump gas. Judging by the inside of the fuel tank, which should be cleaned, the crankcase most likely has some nastiness that you really don't want circulating throughout the engine.

The tank can be cleaned using acetone. That should cut all of petroleum residue. If it's rusty, follow that with phosphoric acid, or Evaporust. Pull the tank out of the frame, first, to prevent tragedy. It'd be a good idea to replace the fuel lines at this time, too. 2018 pump gas is murder on neoprene rubber fuel hose.

More great info... Thanks, much appreciated! Never heard of Jaso... Fuel lines are a bit rigid I must admit.. Will get to this in a few days... Wifey keeps asking... what are you doing? lol

 

[cjpayne]

If you can get pure fuel, then do so. Ethanol can destroy anything rubber in the fuel system and cause high speed lean out.

 

[cjpayne]

Buy a ''sealed'' battery not a acid filled leaker. The acid filled style battery has a shelf life of around a year if you are lucky.

That "leaker" can also get on your paint and wreak havoc on it. Seen alot of bikes with those scars.
Don't try to run your headlight until you have a good battery or it will fry the headlight in a hurry.

 

[Speed Reycer]

A little update as I wait for parts to come in. Pulled the carb. Lots of varnish on the needle. A rebuild is in order. Lots of questions... apologies for this.

The air box is puzzling to me, specifically the boot from the box to the carb. I appears some sort of silicone sealant was used? Was this something done from the factory? If so, does anyone know specifically what was used? It is necessary to have the air box and carb connection air tight? I still need to see if the rubber boot is in good shape though.

Also I included a pic of the inside of the frame minus the tank and battery box. I think the stain must be a battery stain caused by the battery that was in it?. Do I need to do anything to the stained areas?

Lastly, the throttle does not go back to the off position. The spring mostly stays compressed (full throttle position). I thought that was because there is a lot of varnish in the carb . I removed the spring and valve set throttle from the cable. I am able to twist the grip back and forth with the cable moves freely through the cable housing. I tried to pull the cable end (on the carburetor side) when the grip is in the full throttle to get the grip to the off position. Isn’t happening. Am I missing something here?

Thanks again for any advice!

 

[69ST]

You want an airtight seal between the carb and the airbox, to keep out dirt. You'll need automotive weatherstrip adhesive to reattach that rubber boot. Don't bother with silicone, it has no holding power, unless you use the type that is specifically formulated for oil pans, cam covers, etc. That flavor is very tough, also very expensive.

With the carb, source the Dratv master rebuild kit, it contains all-new brass parts, except for the jet holder/emulsion tube. The emulsion tube holes should be physically (not chemically) cleaned by running a thin wire through every single one of the wall orifices...there is no adequate substitute for this.

As for the non-returning throttle...around here that's known as "CT70 cruise control". You might try cleaning everything from the internal twist grip throttle assembly, at the handlebar end to the carb, making sure the vinyl grip cover isn't binding on the handlebar. The cable must be clean, lubed and free of all kinks/bends. replacing the return spring with something stronger won't hurt, either. Don't get your hopes too high, the design leaves a bit to be desired with the stock carb in place.