Newbie CB750 Cafe Project

[ljonny18]

OK, I have not posted for a while ... I am at that stage of the project (that I and I guess most people hate) when I am waiting for both funds and parts

I have been having problems getting hold of a Primary Chain tensioner and guide as they have been discontinued and most dealers don not have any in stock. I did however manager to get ones in v-good condition (especially in comparison to my current parts) from a member on a CB forum:

In the meantime I have managed to sort another level of cleaning out on my engin casings using dry ice :

Before:

After:

They came out pretty good, I pb dont even need to get the motor painted anymore !!! There were 2 layers of old crusty paint (first black and then silver) until it got down to the original metal - It is now (almost) like new and I can now even see / read the original engine bearing codes (engraved into the casing) - I wish I had been able to read them before I spent a whole weekend trying to measure my bearings

 

[YogiBear]

cases look excellent

 

[kazjim]

Looks awesome - tell me more about this Dry-Ice technique ??????

 

[Hoosier Daddy]

Looks like it turned out great! Did you do the dry-ice blasting or farm it out? I was told they are gawd-awful noisy machines.

 

[ljonny18]

cases look excellent

Yeah, im really happy with the result !!! Thanks - Just need to get the top end done next

Looks awesome - tell me more about this Dry-Ice technique ??????

I did / do not know that much about it really... A local company that does it was recommended to me by a local engine builder. Apparently it is a similar process to sand blasting, but a lot cheaper and a lot less agressive / safer to use on soft metal etc...

Here is where I got it done, it is a guy on his own and seems to be passionate about it which is always nice !!! This is his website:

http://www.frozenclean.de/

http://www.frozenclean.de/frozenclean/index.php

Its all in German, but I have (google) translated the basics :

Dry Ice: Dry ice is carbon dioxide (CO2) in solid form. It is nontoxic, odorless and not flammable. The big advantage of dry ice is that after blasting it sublimes completely without having to completely liquefy the residu.

Production of dry ice: Liquid carbon dioxide is fed from a tank into a special machine, called the pelletizer and relaxed. This results in dry ice snow. This medium, with a temperature of -79 ° C is then pressed by a matrix - the result: dry ice pellets in the size of a grain of rice (about 3mm).

Dry ice blasting away Oils, grease, wax-like substances, anti-rust paints, sprays, adhesives, resins, organic substances, graphite, carbon deposits, PU foam, film, concrete milk, grime, brake dust, rust, etc..

Looks like it turned out great! Did you do the dry-ice blasting or farm it out? I was told they are gawd-awful noisy machines.

Have a look at this link above re the process, its pretty interesting... :

http://www.frozenclean.de/trockeneisstrahlen.php

I did not do it no, it cost 40 Euros (50 USD), so I cant complain at having a professional with all the tools do it for me Like I said, its is a lot less agressive than e.g. sand blasting... if you have a real close look at some areas, you can see they are not perfect (apparently they would be better with sand blasting), however I was lucky as apparently (and surprisingly) my engine came up a lot better and easier than others he has done !!!

 

[Nephelim]

Wow, great project thread.
Thanks for the heads up on the dry ice cleaning. I've just googled it and there is a place in my town that does it so that's how I'll get my engine cleaned.
You, Sir, are the dogs bollocks!

 

[ljonny18]

Wow, great project thread.
Thanks for the heads up on the dry ice cleaning. I've just googled it and there is a place in my town that does it so that's how I'll get my engine cleaned.
You, Sir, are the dogs bollocks!

Happy I could have helped !!! keep me up to date how it goes with the cleaning I did not know much about it, and did not know anyone who had previously done it, so I too ka bit of a risk but am v-happy with the results

 

[ljonny18]

I have read that is is a good idea (good practice) to replace the connecting rod nut and bolts when doing an engine rebuild:

Is this really necessary ??? Is it not enough to simply add some loctite red and be done with it ?!? Can anyone shed some light on this ? as if it is reccomeneded I should get some connecting rod bolts orders

Cheers,
Jon.

 

[Hoosier Daddy]

If you use the proper torque spec you won't need the locktite.
I doubt the issue that replaceing them addresses isn't with the nuts coming off, it's with the rod bolts stretching and possibly breaking under stress.
I am sure there is a service spec somewhere for an acceptable length, but if it were me... and I couldn't not find a spec... and after a close examination all looked well... I'd re-use them.

 

[Nephelim]

So just to put info out there on dry ice cleaning:

I spoke to a local company (I'm in Baltimore) and they wanted to charge me $500 to just do the engine only. Which I thought was a bit steep!
I spoke to another company and the chap who answered the phone was an old car enthusiast and he said not to go the dy ice route but to go for soda cleaning. I spoke to a company that does soda cleaning (though you can do it your self if you have a compressor, I think) and they said they would do my frame, swing arm, plates, kickstand etc AND the engine for $300- so $200 less and more being cleaned. Ther frame and other powder coated parts will be taken down to the bare metal.

 

[ljonny18]

So just to put info out there on dry ice cleaning:

I spoke to a local company (I'm in Baltimore) and they wanted to charge me $500 to just do the engine only. Which I thought was a bit steep!
I spoke to another company and the chap who answered the phone was an old car enthusiast and he said not to go the dy ice route but to go for soda cleaning. I spoke to a company that does soda cleaning (though you can do it your self if you have a compressor, I think) and they said they would do my frame, swing arm, plates, kickstand etc AND the engine for $300- so $200 less and more being cleaned. Ther frame and other powder coated parts will be taken down to the bare metal.

Nice - sounds like you got yourself a good deal !!! I wanted to also go the "soda" route but there is nowhere that local to me that can do it therefore I went for the next best option with the dry ice etc... (dry ice seems to be more common in this neck of the woods) In fact it was recommended to me... I guess different places / companys reccomend different methods due to both experience, and what they are best at etc... (but I do think soda is better if you can get it done locally for a good price)

If you are interested in some results of soda blasting, check out one of my threads on the CB forums from and scroll down to a post from "peteseely" his engine was soda blasted and then painted:

http://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=65660&highlight=

"I wouldn't waste time and effort trying to clean the engine yourself. Have it soda blasted, which totally cleans everything ready for painting. It cost me about £60 to have mine done - worth every penny"

 

[ljonny18]

If you use the proper torque spec you won't need the locktite.
I doubt the issue that replaceing them addresses isn't with the nuts coming off, it's with the rod bolts stretching and possibly breaking under stress.
I am sure there is a service spec somewhere for an acceptable length, but if it were me... and I couldn't not find a spec... and after a close examination all looked well... I'd re-use them.

@Hoosier Daddy - I checked the book and spec and taken into account with the milage of the motor and previos state, it basically headed towards replacing them, on closer inpection some of the threads (not all) look not bad, but not perfect... After further investigation I have decided to played it safe and ordered some new nuts and bolts ... Thanks again !!!

 

[ljonny18]

This will be the back of my seat unit. The original was (unfortunately) hacked off by the previos owner although I think this will look good:

So parts are slowly but surely starting to arrive:

Primary chain and tensioners:

These must be the most expensive nuts and bolts i've ever bought (connecting rod nut and bold set):

 

[ljonny18]

Ok, most of my parts have now arrived. There were some (I think seals that were not possible to get hold of as they have been discontinued ... I will have to look into this further as and when I get to them etc ... ) :

Hopefully progress can start to now pick up again

 

[Hoosier Daddy]

That is a beatiful sight on that table...

 

[ljonny18]

That is a beatiful sight on that table...

haha - sure is

 

[ljonny18]

Hi all, sorry i have not updated this thread for a while, this is not because I have been to lazy to do so. but because I have hardly made any progress that is worth posting :S

As mentioned in my previous post, I have received pretty much all of the parts that I require re re-building the bottom end of the engine. I cannot start the re-build until I have got ris of all the old gaskets from the engine casings, which is not as easy / nicer job as I had hoped The gaskets are in the same state as the rest of the motor was and im guessing they have never been replaced. I have read a few tips / tricks to speed up / make removing old gaskets easier, however I decided to just play it safe and slowly keep at it with regular breaks to not risk damaging any of the surfaces etc .... im making (although v-slow) progress This is the last gasket I have to get rid of:

In the meantime (between gasket fighting) I have managed to start working on some more cosmetic jobs, including sourcing an older (SOHC) tank which I managed to get from Sayonara Cycles (www.sayonara-cycles.de) who have some nice bikes - have a look.

The next step for the tank, is to try and get it to fit on my later (DOHC) frame - this will require some fabrication, although (I think/hope) will look good when its done - I love the look / old school style of the older CB tanks... if it does not work, I will have to go back to using the prigional tank and re-think my plans / ideas.

I also managed to get access to a welding machine and finally got my seat unit braket welded up to the frame:

There is a long metal piece (Dowel ???) tightly fitted through the middle of the seat bracket and frame and then all welded up, so it is very strong I am quite pleased with the result, and hope it looks good once I have (tried) made a custom seat to fit.

Thats about all I have so far... I hope to be finished with the gaskets this week depending on time, give the motor a final cleaning in the parts wash, and get started on the bottom end re-build again.

 

[YogiBear]

good work with the hoop, looks like a flawless blend into the frame.

 

[Hoosier Daddy]

good work with the hoop, looks like a flawless blend into the frame.

No Doubt, nice job! Was that hoop store bought or did you have it custom bent?

 

[ljonny18]

No Doubt, nice job! Was that hoop store bought or did you have it custom bent?

Thanks, the hoop was custom made for the bike. I had a look around online for a ready made hoop but did not find anything that was a) the exact size / length I wanted, or anything that was a reasonable price with postage to Germany (where I am currently based).