CB750 Barn find project - First Timer

[Spitfire]

Here's my high tech stand that I used rebuilding mine worked great from bare frame to the finished article.

[Underdog1]

Here's my high tech stand that I used rebuilding mine worked great from bare frame to the finished article.

Good effort! Might knock something similar up when the bike is ready to go back together circa Christmas 2027.

As far as engine stands go, there are a few work bench top cb750 specific ones on eBay for <£40, but also a lot of these:

http://www.mandp.co.uk/index.php/default/engine-stand-1500lbs.html

Would this support an SOHC engine without any sort of adapts plate being needed?

[SteveD CB500K0]

On another note I entered a competition to win some tyres and had to hold a tyre out in each hand for as long as I could. Came second to some unit, gutted! Could have done with some freebies! 

I went on Tuesday and must have sat on 50+ bikes, not many of which were <£20k

How long did you manage with the tyres?

2 mins was about the limit when I was watching.


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[Underdog1]

On another note I entered a competition to win some tyres and had to hold a tyre out in each hand for as long as I could. Came second to some unit, gutted! Could have done with some freebies! 

I went on Tuesday and must have sat on 50+ bikes, not many of which were <£20k

How long did you manage with the tyres?

2 mins was about the limit when I was watching.


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I got around the 2min30 mark with the winner beating me by 15seconds. If it had been another day maybe I could have one! I got a load of Dunlop branded crap though and met some really hot chicks back stage so wasn't all bad 

[Laverda Dave]

You meet the nicest people on a Honda......

[Underdog1]

Been reading through the shop manual and it seems just to do the top end i need a myriad of tools including:

a micrometer, inside dial gauge, valve remover tool, valve guide remover, small dial gauge, valve guide driving tool, valve guide reamer, vernier caliper, cylinder gauge and probably a few more.

Obviously doing it this way is mega by the book, what i'd like to know is if there is some sort of list of the common things that need to be done or is it a case of absolutely everything needs to be put under the microscope? Im not one to cut corners but just thought I'd check before i shell out for a load of tools ill probably only use once.

I cleaned up the cylinder head cover and barrels today as they were still pretty filthy. Got the pistons out to measure the ring piston gap (which are all < 0.1mm on each) and cleaned up the pistons (one of the piston rings fell apart as i took it off  ).

The top of all the pistons look like this (the bits with carbon left on are low spots):



Is this a red flag or typical wear?

[Bryanj]

Normal(ish)

[Underdog1]

Normal(ish)

just waiting on some micrometers to arrive in the post so I can measure a few things up, apart from the piston diameter at the skirt end 90 degrees to the hole being less that 60.85mm and the piston ring grooves being excessively worn is there anything else I should look out for?

Also I need to get a valve spring compressor, is there a need to spend much money on this or will a cheap flea bay one do the job just as well?

http://www.ebay.co.uk/itm/262711661056?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

This project is going along painfully slow at the moment as I've been really busy at work and will be off out the country for another 5 weeks in Jan. Need to try and get as much as I can done over xmas!

On a positive note I bought a cheap engine stand and adapted it to hold a motorbike engine, probably £50 all in which I was happy with! Will get some pics up when my phone stops being so tempermental.

[Underdog1]

Here she is, living room engineering at its finest!

[MarkCR750]

Nice work!

[yozzer74]

I take it your not married then

[Rozabikes Tim]

Wow thats a big decoration on your tree. Ho ho ho....

[Underdog1]

Wow thats a big decoration on your tree. Ho ho ho....

I've worked hard getting my girlfriend into motorbikes, bought her a jacket and booked her CBT for xmas so she's actually cool with it 

I'm taking my cylinders to a machine shop today to get measured. If I do have to get them rebored is there any reason not to go straight to the 1mm max rather than doing the minimum necessary?

Hopefully it will be within specs and I won't have to bother but just thinking if I'm going down that route I might as well get the most out of it right? The workshop doesn't state what diameter the cylinders need to be rebored to for the different size overbite pistons which is a bit confusing 

[Spitfire]

That's a a great stand, likes it

Cheers

Dennis

[Underdog1]

Cancel my last i had the barrels measured up and they are all good, just getting a hone.

Also took my head in and they checked all the valves sealed correctly but they didn't check any clearances as i still had the valve springs all attached (my spring compressor actually arrived today and i went straight from work to the machine shop) but they were confident they were all good (they were both also motorbike enthusiasts), should i be alright to take their word on it or should i still take the valves to bits? They did however find the head was ever so slightly warped so is getting a light skim.

Guess thats me about ready to split the cases then 

Jut thinking ahead slightly for once, what gasket/seal sets do you guys recommend? I see the cycle x set gets good reviews but seems difficult to get in the UK..

Theres cheap 'NE brand' ones on eBay and some even cheaper seemingly unbranded ones but I'm wary of either so suggestions appreciated!

That's a a great stand, likes it

Cheers

Dennis

Thanks mate, made more sense to me to buy a cheap engine stand and just adapt it for a bike engine rather than buying a dedicated bench top engine stand for almost the same price.