Engine rebuild Parts list

[Dolomite_]

After googling and having a look through older posts and not finding anything, I thought I'd ask.

Does anyone know if there is a list of what to replace when doing an engine rebuild? It's my first engine rebuild, the furthest I've been so far is taking the barrels off.

What is definitely worth replacing and what is worth replacing because its already stripped?

[Johnwebley]

You really need to measure everything,

Bores plus  0,004 need to be bored,

Obviously mains,big ends checked,

Rubbers in clutch cush drive,

Oil seals,

Honda engineers did a great job,

My 500 recently had a refresh,

After 80,000 miles the bottom end just needed clutch Rubbers and primary chain,



Sent from my SM-A546E using Tapatalk

[taysidedragon]

If you look for Nurse Julie's engine rebuild, (link is on any of her posts) you'll see what is involved.

On a worn engine you may need new pistons and rings, valve guides, new bearings and seals, check camshaft tensioner horseshoe and guides, new camchain, primary chain and damper rubbers, check big end and main bearing shells plus a full gasket set.
A full rebuild is not cheap!

[McCabe-Thiele (Ted)]

If you budget for £1200 to rebuild the engine (inc rebore) I suspect that is close to average today provided the head & camshaft are okay.
That does not include things like Soda Blasting or anything cosmetic.

[Dolomite_]

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.

[Athame57]

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.

[Dolomite_]

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?

[McCabe-Thiele (Ted)]

My figure is £1200 is for parts then fitting them yourself - obviously having a rebore done by a specialist is included.

Mileage although a factor is not the whole cause. An engine that has stood for long periods in a shed or similar will deteriorate. Internal corrosion from condensation & old engine oil sticking clutch plates etc etc.

My parts from memory were Rebore & Pistons by Trigger, two Helicoils and machining for the tensioner bolt upgrade. I had to replace all the crank bearings, a couple of gearbox bearings, Primary drive rubbers, PD bearings & PD chain.All engine gaskets & seals plus camchain, one used valve, valve stem seals. Full Gasket Set plus some gaskets not included in my set. Oil filter & new sump plug. Hondabond & Locktite tubes. Clutch friction plates & clutch drive rubbers. Some replacement engine casing bolts plus zinc plating of  many bolts. Replacement side casing fasteners. My bike came with new tensioner blade and some new cover gaskets. Oil pick up pipe tubing, new circlips as required I will have missed a few bits off this list like some replacement engine dowels.

[Bryanj]

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

[Athame57]

How were the bores?

No problem!

[Dolomite_]

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.

[McCabe-Thiele (Ted)]

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.

You might already know, it's worth mentioning that whoever does your rebore should be aware of the fine tollerances Honda used on these engines. Ideally the engine specialist should be someone with Honda specific motorcycle engine experience.

[Laverda Dave]

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👍

[Dolomite_]

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?

[Laverda Dave]

I would contact either Nurse Julie & Graham (Trigger) or Bryanj both are on this forum. It goes without saying they are both the best at what they do and having been around Honda sohc's for ever they know what they are doing. Graham has just rebored my cylinders with some NOS Honda pistons and rings I purchased from Ted and replaced the valve guides and some valves. The postage cost to send the barrels and head to Graham was £9 via Royal Mail, next day delivery. Quicker and cheaper than going by car to your local rebore man!
Going back to a point made earlier by Bryanj, my barrels had 43k on them (or so I was told by the PO) and were on standard bore. They had to be bored out to .50 so unlikely you will get away with a 0.25 rebore on yours but until they are propely measured by whoever does the rebore you won't know so dont jump the gun and buy a piston kit yet as you may be wasting your money.