Topic: Captain Rats - CB750K1 Project

[captain rats]

Hey guys,

Thought I would post up my project and introduce myself. The name is Luke but i picked Captain Rats as my handle. It sounds like a cool name but down here it means someone who is a bit lacking in the brains department.

I live in Sydney Australia and have done up a few other bikes in the past. I was really into old vespas and lambrettas and had a few rare ones. My favourite was a cheap ass PX that i spent loads of time and not much money on. Full bare metal.



I then fixed a write off Harley 48 Sportster and added some bits. I sold this to buy some other projects, one of which was my CB750. Cool bike but i felt like a real poser on this one.



So i was looking in the local motorbike trader and saw a Honda CB750 advertised as 1973. Not running but an Australian bike. After researching the webs and finding this forum i realised the picture showed the signs of an earlier bike and after some discussion turned out to be a 1971 or somewhere in that range. It had a 1973 engine that was frozen. It had been in Lismore (7hours from Sydney) all its life with some mods. I drove up and picked it up with my daughter. Here is how it looked perched on the back of the ute.






I thought it might be easy to get going but it really wasnt. I even contemplated selling and buying a bits and pieces K1 which was running. Some advice from here, good advice, saw me straight. I have decided to keep it and do it up. It has some good points, but also has some bad. Look at the pictures will probably tell you but the speedo is stuffed (broken lens and left in the rain). Engine is k2 and problems, double discs front wheel(?) rusted out pipe, rusted wheels, bars, cracked side covers, headlight ears, rear guard, broken hydraulic brake seized rear brake, missing electricals, missing electrical side cover, jammed clutch, seized throttle, the list goes on.

As much as folks hate to hear it it is not really worth a factory restore. I am going to modify it cafe style and keep the bits so if someone later felt like it might be a concours resto they can go for it. I really just want to ride it to work as often as i can and race around my neighbourhood scaring cats.

I like reading about projects so i hope you guys like reading about mine.

[70CB750]

Welcome aboard, captain 

[brandEn]

Looks like a perfect donor bike for modification. Welcome to the forum.

[Garystratos201]

Welcome to the jungle. Its a rough project at best but we all started somewhere. My K1 was in pretty rough shape when I started but looking much better now. Check it out............gary

[captain rats]

Have started removing some bits and getting stuck into some work on the bike.

I was lucky enough to get to the USA for a few days and picked up some parts. My preference for bikes is not to undo 40 years of character by painting over history. I do like shiny new looking stuff but love to think about the story behind each scratch and dent.

In saying that I have decided not to paint or powder coat my bike or frame as much as I can resist. I was lucky enough to pick up the patina'ed tank and headlight bucket in my favourite colour. The tank has some dents and scratches and I know I will get every dick head in town ask me "how long till you finish it" but I prefer it this way.

I also got a nice oil side cover to replace my cracked one, and a great set of gauges which I hope to use for parts to restore my k1 originals which had cracked glass and were in the rain.

My favourite purchase is the exhaust. It was a bit of a present to myself and a little exuberant but I love this thing. It is a motogpwerks stainless system. I get excited about this thing every time I look at it. It is like seeing a beautiful woman, it nearly takes away your breath. I will be posting a video of it on YouTube when it's on and running but I saw a video of a cb550 on YouTube with the same one and the sound is incredible, I recommend you look it up. It will only sound better with an extra 200cc. It cost me $500 clams but worth every cent I reckon. I was also lucky enough to meet Chris Redpath, he is a great bloke, a straight shooter and a real craftsman. I was hoping to do a bit more shopping at another shop but got involved in a few yarns and look around his shop and the old race bikes and couldn't leave.

Anyway can't wait to get these bits on but there is some work to do before then. Better get in the garage.

[captain rats]

Here is link to that cb550 with the motogpwerks exhaust, sounds tough.

http://m.youtube.com/watch?v=2o3uJgMLdxU

[Retro Rocket]

There's a few guys on the forum running his pipes Rats, I have one as well...  Forget my question in your gallery post, you answered it here...

[snowman]

Welcome to the forum, I will definitely be watching.

[captain rats]

Thanks guys,

I have small technical question.

I post using an Ipad especially when it comes to photos. When I view my posts on my nexus the photos are upside down sometimes. Can you tell me if the photo of the tank and exhaust are upside down or not?

When I look on my nexus tablet it is, and on the ipad it is not.

Thanks.

[edhaeuser]

Thanks guys,

I have small technical question.

I post using an Ipad especially when it comes to photos. When I view my posts on my nexus the photos are upside down sometimes. Can you tell me if the photo of the tank and exhaust are upside down or not?

When I look on my nexus tablet it is, and on the ipad it is not.

Thanks.

Yup, Upside down.

Welcome.  I am building a CB750 also.  There is lots of good information as well as a host of very knowledgeable people here.

[captain rats]

So I did a bit of work today, some good but mostly bad. Will get to the bad later. Got a bit of it apart now. It is a bit older and has a bit more surface rust on the parts than i had hoped, luckily they are the parts i am replacing. I took the fork off and front wheel off, next will be the rear.

I need to dismantle to get my new engine in it which should arrive this coming week. Here are some photos of it so far. It looks to have had a steering dampener installed early in its life which looks quite cool. I'm gonna leave it on as it fits the build I am after.



I also put some period correct after market shocks on it, they are Konis, i am interested to see if they still work or not but the nice thing is they dropped the rear of the bike by 15mm which might end up being a nice stance, we will see.



When I took the fork out I found out the unicorn is cracked! Bad news.. I am lead to believe these are hard to get. I was intending to keep my gauges and unicorn and got a great deal on some k2/3 gauges from tango911(thanks bro) in order to use the parts to restore mine. Have a look at the photo.



You can see a crack in the rhs top fork clamp. I am quite annoyed at this. As it is cast and requires a lot of torque I am sure this cannot be fixed (even after a workout with that masculine looking forearm building device in the background). I have looked on eBay but I cannot find this type with a hole for a red warning light.

This is the light for it.



Is this top clamp unusual or something? It is not modified as it looks factory, any ideas?

Does anyone have one of these for sale or am I better off just buying some after market gauges and top clamp? I would probably prefer to keep it as stock as possible so if one can point me the right way I would appreciate it.

[Retro Rocket]

Thats a Japanese model top tree or bike mate, those lights were  on Domestic Japanese bikes only...

[Dream750]

Retro Rocket nailed it ... as that’s a Japanese market top triple tree with the red over speed warning light. I also noticed your tail light has the Japanese market lens with the pronounced amber side inserts. Perhaps you have a Japanese market bike (JDM), does your rear fender decal look similar to the one below?

[Retro Rocket]

Good spotting on the tail light Dreams..

[cheftuskey121]

Super interested to see how this pans out. Good luck and keep photos and text coming! My next bike will absolutely be a modified style. My bike was a very good candidate for restore so I went that option.

[captain rats]

That's exactly right, you can't quite see it but the sticker is in Japanese, and if my katakana is correct it is a cb750. Not sure if this values or de-values the bike, given the condition I don't think it matters either way. I am keeping all the original parts from it in a box so if anyone was keen they could turn it back.

So I did a little work today. I was on the fence about a clean CNC triple tree top with generic mini gauges or the originals. I decided that if I could rebuild my gauges I would run the stock set up with clip one which arrived today. Well good news, I took some k3 internals and replaced my rusted k1 odometer/speedometer. It all fits well and I must say the Japanese are some craftsmen or women. They are beautiful inside. Mine had been dented and cracked and had filled with rain this rusted the hell out of them. Tango 911 went above and beyond getting the k3 gauges to me and a great price so I am stealing the internals, surround and glass. Just going to order the new faces for them and laughing. Will get some photos up. I also bought a new computer that didn't work so the photos will have to wait.

What do you think of a replace rhino/unicorn situation I have?

I am debating a used k1 no hole on eBay for $200

Or this one:
http://www.yamiya750.com/index.php?main_page=product_info&cPath=144_72&products_id=715

It works out at $300 bucks but is less likely to crack when I take the fork legs in and out as it is newer and they say they have reinforced it. Still what is this #$%* made of to be costing so much. I reckon I could get a one off CNC 'd one made for close to that.

So what do you think? Has anyone got one for sale at a better price?

Gee'ed up about rebuilding the gauges, was a fun night, hope they work.

[Dream750]

Japanese market bikes have a cool factor. 
 
Too bad about your cracked tree.
 
Whichever replacement style of OE upper tree is decided on – you want to ensure the D-shaped washers are installed to prevent cracking in the future. Here’s a good solution from MCRider for missing washers:

http://forums.sohc4.net/index.php?topic=72765.0

[Mugen_Stumpo]

more pics of the PX, NOW!!!

[captain rats]

Retrorocket, how are those pipes for fitment? I not at that stage yet but was keen to hear how and where you mounted the can section, mine has a small threaded bung and it looks easy to get/make a small bracket off the frame somewhere?

Dream750, thanks for the advice and good spotting. The last thing I want is to send another rhino horn into the landfill.

Gary, had a look at your project, nice work, you leaving the tank in og paint? Looks good like that.

Mugen, will put up some pics of that PX when my stupid computer is replaced. I have a you tube video of it I made for a guy who wanted to hear it but couldn't see it when it was for sale. Hopefully the link works OK. Thanks for showing interest.

http://m.youtube.com/watch?feature=plcp&v=156cCoN98cY

[Retro Rocket]

Retrorocket, how are those pipes for fitment? I not at that stage yet but was keen to hear how and where you mounted the can section, mine has a small threaded bung and it looks easy to get/make a small bracket off the frame somewhere?

Dream750, thanks for the advice and good spotting. The last thing I want is to send another rhino horn into the landfill.

Gary, had a look at your project, nice work, you leaving the tank in og paint? Looks good like that.

Mugen, will put up some pics of that PX when my stupid computer is replaced. I have a you tube video of it I made for a guy who wanted to hear it but couldn't see it when it was for sale. Hopefully the link works OK. Thanks for showing interest.

http://m.youtube.com/watch?feature=plcp&v=156cCoN98cY

I had mine made without a mounting tab because i have modified the frame, i'll weld on a bracket when i know where its going....

[captain rats]

Some news since last time.

I managed to source a triple tree from one member of the forum, an all round good bloke who has helped me with parts before. Looks like I am gonna be keeping some original era parts on it.

The other news is that my engine turned up. The engine is a 107 number so a k1 to match my frame, so that's nice. It is a rebuilt one at that which I found on the other side of our country. Strangely it cost me $70.00 to ship this 100kg monstrosity across 3000 miles. Good deal hey?

The seller said it needs the tappet cover bolted up properly, the starter put in and the head bolts tightened after the first bit of running in. Here are some photos of it.



It looks to me that there are some bolts and rocker parts missing, what do you guys think?

[Retro Rocket]

I would get someone that knows what they are doing  have a good look at that head, there seems to be mismatched bolts in the cam towers {that would worry me} and it looks like the cam lobe on no3 cylinder is damaged, get it checked out before bolting it together....
Looks like you need rockers and shafts as well.....

[captain rats]

I would get someone that knows what they are doing  have a good look at that head, there seems to be mismatched bolts in the cam towers {that would worry me} and it looks like the cam lobe on no3 cylinder is damaged, get it checked out before bolting it together....
Looks like you need rockers and shafts as well.....

Yeah am going through it slowly, that is graphite grease on the lobes..

[Mugen_Stumpo]

your rat PX is badass.. i have a px200e myself...

Gl with the build

[Garystratos201]

Cant see the photos.  Dont know why............Gary