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Messages - Dolomite_

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16
CB350/400 / Re: Engine rebuild Parts list
« on: March 02, 2024, 09:59:50 AM »
Ive tried to figure it out and looked through other posts. But how do you work out the shells needed from the crankcase codes?

Would these be the ones to use for the new crankshaft?

17
CB350/400 / Re: Engine rebuild Parts list
« on: March 01, 2024, 10:51:41 PM »
Both those look same to me and would save you spending roughly £80 on big end shells.
Plastigauge is accurat when used correctly but you need a main bearing pin size to start from.
What are the letter codes from the rear of your crankcases?

The crankcase code is BAAAA.

I'm near Preston.

18
CB350/400 / Re: Engine rebuild Parts list
« on: March 01, 2024, 10:14:25 PM »
If 400four bits has one he is a member on here as as far as i know fully trustworthy.
Personaly i would buy crank and rods as chances are the big ends would be ok and you would only need to buy mains.
No offence meant but if you are ordering a micrometer to measure the mains you wont be accurate enough, the correct use of mics is an art and the accuracy required is not easy to learn, you would be better taking it to a good engineering firm for accuracy

just thought I'd give it a go with a micrometer and plastigauge. If crank and rods are the way to go I'll do that.

What would you go for out of these two: option 1 https://www.ebay.co.uk/itm/312044879538?itmmeta=01HQXPVR92HVDMQ5AS8Q6HNVN8&hash=item48a752feb2:g:ZS4AAOSwi0lg3u8q

option 2 https://www.ebay.co.uk/itm/313344578679?itmmeta=01HQXPVR92FYBSGWTXTKKDEPWH&hash=item48f4cad477:g:13QAAOSw5FRgbExl

19
CB350/400 / Re: Engine rebuild Parts list
« on: March 01, 2024, 06:55:23 PM »
So after doing some googling and watching videos on how to measure the crankshaft, I've ordered a micrometer. So I'll try to measure and work out the sizings for the shells, buy 1 set, measure with plastigauge then order a full set of shells or 1 set of the next size up and plastigauge again.

Could I get some opinions on the crankshafts I have linked?

400fourbits also has one for sale. https://400fourbits.co.uk/

After Teds recommendation could someone take a look at these 2 options https://www.ebay.co.uk/itm/312044879538?itmmeta=01HQXPVR92HVDMQ5AS8Q6HNVN8&hash=item48a752feb2:g:ZS4AAOSwi0lg3u8q and https://www.ebay.co.uk/itm/313344578679?itmmeta=01HQXPVR92FYBSGWTXTKKDEPWH&hash=item48f4cad477:g:13QAAOSw5FRgbExl

Or if any of the other ones I've linked seem good let me know.

20
CB350/400 / Re: Engine rebuild Parts list
« on: March 01, 2024, 06:49:41 PM »
I bought a crank & con rods from DK for my 500 - they were as described - the con rods shell were like new. 👍👍👍

Whats DK?

21
CB350/400 / Re: Engine rebuild Parts list
« on: March 01, 2024, 03:35:06 PM »
I'll give a good clean tonight or tomorrow and get rid of all the oil and grime. Its my first time doing a rebuild but it doesnt seem too far from these replacement crankshafts.
https://www.ebay.co.uk/itm/375274886316?itmmeta=01HQXA10VEERSW3BT3Y66F6C4R&hash=item57602054ac:g:o84AAOSwrFdkoB9r&itmprp=enc%3AAQAIAAAA8AKr4Ep4hVTll7AIMNUs5vK1xxCRmHXus9Yx3rmrZk5CIOoba1BWmYU%2FbUVe1KdN98AJY%2FkMjnFxa4%2BdqVhws3HE4MtLbs9V8HRSd1DBc4xQdrTuTPdEMyfIGCqpem4Ds0SuJSn9wEI3TOLUcjNqXsIgJD8xoDjJuB%2F1z0oQlqZ0nBxUw3DG80g2mJVXP6Yz1e%2FJMq4SfdaGKe44zB25wJ0lInFKlFqbST%2BezZBZxKtg8zQmNhWjpKXhwXfo%2F3MsxG3nZPJS6pYoDx%2BuD0zaGetIgO5%2FWzu%2FXd3jveFJ9Ln%2Bxr2QtlKyMwtg5IuhrLtreQ%3D%3D%7Ctkp%3ABk9SR-SNhKq_Yw

https://www.ebay.co.uk/itm/204673292768?itmmeta=01HQXA10VE5YNYFQNRPQ4YSX8C&hash=item2fa77a99e0:g:RDQAAOSwBfRlw7JN&itmprp=enc%3AAQAIAAAA0FqCbxO1e6qmujg7mrLyab2Or9HCuS6dvjx2KgdPQ4xMOPVdPoASoOyTuGxMEuVuQWU0FH6Ge1Ub3nnnWlNm2N5kvx5CA1gahlQsh8hn2XkNLrxAlit7b8Y2cTTbqduHvrRm0BG7Cqm711Mi25pk4te2yAUf0Cxm%2B%2FzRI3C3scZxVe8xqp0tqnFKPQTdmKGZIX4PjOHt%2BzLFVLSpkGnBYeF%2B9nLEKQl6FBSi9gY%2FwfeyrW9N7a48QPzZ9r2RmdngbxZDtO4J91vXKCB2pbbugRU%3D%7Ctkp%3ABk9SR-SNhKq_Yw

Update, Julie has just updated me regarding my rebore. Looks like there was silicone mastic blocking some oil passages. Regarding a replacement crankshaft, they dont seem too bad price wise.

Would it be more hassle trying to get new bearings to fit a new crankshaft and my current con rods? Or would it be easier to fit new bearing to a crankshaft that comes with the con rods?

There are 2 on ebay. Option 1 https://tinyurl.com/mrxffku7 Option 2 https://tinyurl.com/mu7fny3e

Without con rods. Option 1 https://tinyurl.com/3fcbp249 option 2 https://tinyurl.com/y6un5ha9
 

22
CB350/400 / Re: Engine rebuild Parts list
« on: March 01, 2024, 02:31:17 PM »

Before you go and spend a shed load of cash on new shells get yourself some green plastigauge for £10 and measure the shells you have. Take some photos and post them here and do the same for the mains. The experts on here will be able to advise if the shells are scrap or useable (and assuming they are within tolerance after measuring with the plastigauge).
As has been said previously, please make sure you have made a note of where each individual half shall has come from and if it came from the top or bottom crankcase half. Post some photos of the journals as well.
One item not mentioned for your parts list is a tube of Hondabond. You will need this when assembling the crankcase halves. It's not cheap and don't be tempted to use instant gasket, you'll regret it when it blocks up the oilways and wrecks a newly rebuilt engine!
[/quote]

Ive ordered some plastigauge green, should be here next week.

My nail doesnt catch on any of the crank case bearings but does slightly catch on the con rod bearings. I went to the engineering firm at lunch today, who fixed my tensioner for his opinion, he's been doing engine work for 40 years and has been recommended by a local restorer who uses him who has done work on previous cb400fs he was restoring. He said they dont seem too bad and would just replace them like for like. I'm going to wait until I can test it with the plastigauge before I pull the trigger on anything.

Upper crank case




Lower crank case



Con rod example



Another con rod




23
CB350/400 / Re: Engine rebuild Parts list
« on: March 01, 2024, 02:23:44 PM »
If you havent looked at crankcase how are you seeing the ends? And they are supposed to be shiney where they bed in, put up pics for advice before spending a fortune

I hadnt taken the con rods off then, but I have now.

24
CB350/400 / Re: Engine rebuild Parts list
« on: February 28, 2024, 03:22:18 PM »
Disagree about shells, inspect yes but replace only if wor and make sure you know where they were originaly

I've not looked at the crankshaft bearing just yet but the big end bearings seem ok, still slightly shiny. But I think I may as well replace them.

25
CB350/400 / Re: Engine rebuild Parts list
« on: February 26, 2024, 01:04:46 PM »
Are the NOS Honda ones new old stock?
Sounds like an oxymoron dunnit?  ;D

FFS I read it completely wrong :D. I've never seen new old stock abbreviated :D

26
CB350/400 / Re: Engine rebuild Parts list
« on: February 26, 2024, 11:02:37 AM »
Thanks, Laverda Dave, I'll give Nurse Julie/Graham a dm. Not purchased any pistons yet, I'm waiting until I've sorted everything out with the engine. I was just going to go with the Davis Silvers Spares oversized ones so I know they will definitely fit but are there any that might be better?

Are the NOS Honda ones new old stock?

27
CB350/400 / Re: Engine rebuild Parts list
« on: February 26, 2024, 08:48:20 AM »
I agree with all the above and would add a caveat to the rebore work and that is be very wary of the man down the road who is used to reboring car or British motorcycle engines. Japanese motorcycle engines run very tight tolerances. The individual pistons should be measured and numbered. The bores are machined to suit the individual pistons.
I second Ted & Bryanj's recommendation, get the rebore done by someone who knows what they are doing with regards to these engines. The specific tolerances are in the Haynes manual.
I had a Honda CB250RS rebored by a so-called specialist five years ago. Despite giving him the tolerances he decided to do it his way as he thought the tolerance was too tight and the piston would sieze. Guess what, this is exactly what happened but not because it was too tight but because the 'specialist' bored it out as he would a British bike and didn't tell me. The engine used a litre of oil in the space of 50 miles, the bike sump only holds 1.5 litres, result a full seizure on the M40 motorway on a newly rebuilt motor. There was a big hole in the top of the piston on inspection.
Only use people who are recommended by others on this forum to save yourself a lot of pain and money👍

Good point Laverda Dave. Ive had a quick search through the forum but couldnt find any mentions, do you know any places in the Northwest you would recommend?

28
CB350/400 / Re: Engine rebuild Parts list
« on: February 25, 2024, 06:16:47 PM »
Have you priced a rebore recently, the last four sets of 500 i did did not clean at 0.25 as the bores were "barelled" had to go to 0.5

I've not had to rebore anything yet. Im guessing its going to be atleast a couple hundred pounds. I'm going to contact an engine machine specialist near me tomorrow.

29
CB350/400 / Re: Engine rebuild Parts list
« on: February 25, 2024, 03:59:41 PM »
I guess it depends on what might be wrong. I've just spent £450.oo on parts and £700 for labour, price agreed beforehand, presently my bike is still in the garage. I was advised to get the rebuild because of leaking gaskets and some seals. I opted to get the cam chain, it's 'horseshoe' and tensioner blades complete changed while things are open and a broken piston ring was also found. Nothing else that really matters has come up. Mine is a 1978 CB400F with 40,000 on the clock, the last 12,000 were gentle ones with me.

How were the bores?

30
CB350/400 / Re: Engine rebuild Parts list
« on: February 25, 2024, 03:30:24 PM »
The bike has done 28k but I dont know how much wear that might cause. I think it might be a case of I'm down there already so get a rebore of 0.25mm done.

Is the estimate of £1200 getting someone else to do it? From the rough estimates in my head, I was expecting 600-700 just for parts and doing 90% of it myself.

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