750 Top end rebuild

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Re: 750 Top end rebuild

Postby Freddy » 13 Oct 2018, 07:59

Started up quickly, just needed a little choke (normally don't ever use it).

Little rattly, tightening up the manual chain cam adjuster quickly fixed that. Bike washed and ready for a road test. Unfortunately weather is on/off rain (forecast to be this way for the next few days) so hasn't hit the road yet.

As I couldn't go for a ride pulled the chain and generator covers off and buffed them up using a polish wheel fitted to the bench grinder.

Now its just a case of waiting for the weather to fine up. Can't complain, major parts of the country have been in a bad drought for quite some time so the farmers are appreciating the rain.
Freddy
 
Posts: 385
Joined: 06 Sep 2017, 12:06
Location: Sydney Australia

Re: 750 Top end rebuild

Postby Freddy » 15 Oct 2018, 03:26

Final update ......
Did about 100 klms, tested fine.

Pulled valve cover off to recheck valves, no appreciable change. Checked head bolt tensions, no difference. Synced carbies .....

Ready for another 100,000 kilometers of faithful service. Plan to dump the oil after this coming weekends planned 200+ kilometer ride with the regular crew. It's been advertised as not a fast ride (which really means not insane), so perfect for breaking in the engine.

Why I was focused on time to do the task was just out of curiosity to know what a shop should change to do a similar top end overhaul. If I added the broken days together I believe it took about 3 full days. Say 25 hours. At a charge out rate of $100 an hour that would be $2500 in labor. While I don't have an exact record of parts and machining costs, I estimate it was around about another $1200 (pistons, gaskets, bore cylinder, cut valve sets) .

So an all up cost of around A$3700 if I had to pay someone. At current exchange rates that's US$2600, or Sterling 2000. Probably explains why not many people would see this as viable. But to me $1200 in parts and 3 days work was WAY cheaper than $20,000 for a new bike (and there currently aren't any new ones I like enough for one reason or another to buy). And then you still have to throw time and money at the $20,000 bike sorting the bugs out (snatchy throttles, crap suspension, etc,) Just the relative simplicity of the 750 Zephyr is a big plus in my book.
Freddy
 
Posts: 385
Joined: 06 Sep 2017, 12:06
Location: Sydney Australia

Re: 750 Top end rebuild

Postby David Richard » 15 Oct 2018, 06:23

hi freddy that's all worked out ok for you ,I don't have your skills to do that but I think if that was me I would have found another bike and just swapped the motor over.in the uk there have been a few 750 with low miles on for less than 3k all in different states of condition but its good to know the engines go that far ,david
David Richard
 
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Joined: 04 Sep 2017, 21:21

Re: 750 Top end rebuild

Postby Freddy » 15 Oct 2018, 13:28

David Richard wrote:hi freddy that's all worked out ok for you ,I don't have your skills to do that but I think if that was me I would have found another bike and just swapped the motor over.in the uk there have been a few 750 with low miles on for less than 3k all in different states of condition but its good to know the engines go that far ,david


Hi David,
In my neck of the woods A$3000 will buy a poorly maintained Zephyr 750 with around 100,000 kilometers on the clock. After travelling miles to pick it up, haggling over the price, get it home etc, etc. about the only thing really useful to me would be the set of barrels (to have them rebored oversize in order to make the changeover faster). AND I'd have to dismantle the bike.

Alternatively, for around $300 I can get a set of second hand barrels ready to be reconditioned delivered to my front door.

P.S. There is a Zephyr 750 currently listed for sale with just under 30,000 kilometers on it. They are asking $8000 (a jaffa D1) and it is just a short 4,000 kilometers away on the other side of the country.
Freddy
 
Posts: 385
Joined: 06 Sep 2017, 12:06
Location: Sydney Australia

Re: 750 Top end rebuild

Postby David Richard » 15 Oct 2018, 20:59

hi freddy point taken now it makes sense ,that's a shame that's parts are scarce ,I have a friend who has contacts in the usa who buys classic bikes enough for a container and then ship them over here ,he makes a good living from it ,but I think its a bit further to you ,david
David Richard
 
Posts: 114
Joined: 04 Sep 2017, 21:21

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