25 replies to this topic

[bikenutmart]

Hi, Wondered if i can hone the bores at home, its a 1275 A+ block on std, no wear ridge, no scores, just some black/ rust marks that are proud of the bore, could i do this with some abrasive paper and oil, i do have small hands!! Mart.

[Carlos W]

You can get home boring tools which go on a drill, I'm not sure how good they are though.

 

The block really needs measured for wear properly

[Spider]

You might get a variety of answers on this, but this short answer is no.

 

Some more info here

 

http://www.theminifo...gine-machining/

[Carlos W]

You might get a variety of answers on this, but this short answer is no.

 

Some more info here

 

http://www.theminifo...gine-machining/

 

Really interesting read. 

[panky]

I've just done this on my 1275 engine. After watching a few tutorials I got the cheapest honing tool I could find off ebay and had a go using engine oil and WD40 as a lube. I ended up with the cross-hatched pattern, but not quite as neat as a machine honed bore, but an happy with the results. Checked the gaps on new rings and they were bang on so with a little careful running in they should be fine. I spent about 30 seconds on each bore and the honing stones had completely worn away, they were very cheap after all.

 

There are still a couple of marks but they passed the finger nail test.

 

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Edited by panky, 10 July 2017 - 08:53 AM.

[Carlos W]

Get it under load as soon as you start it

[ozz1]

Whilst your at this stage its worth checking for bore ovality or taper - I had a block I thought by feel and eye was fine, but turned out to have 9 thou of taper! measure with an internal micrometer or dial bore gauge - can get them of ebay for £40. Also unless you are using the orginal pistons in right order you will need to have the bores rebored to match any manufacturing tolerences in the new piston.

 

As for honing you can buy a deglazing tool of ebay for £25...a few youtube video's should give you the right idea - its easy to bugger up, if you go to slow or dont use enough oil...

Edited by ozz1, 10 November 2016 - 01:45 PM.

[bikenutmart]

Was hoping to use the existing pistons in the right order( i marked them) with new rings. Mart. Thanks for all the replies.

[ozz1]

Was hoping to use the existing pistons in the right order( i marked them) with new rings. Mart. Thanks for all the replies.

Check the compression ringlands on the pistons - see what size feeler gauage you can slide in. Any more than 0.004" for a performance build means the pistons are shot. Not sure what the max tolerance for a standard engine is, but if I was going to all the bother I woudn't use a piston with with more 0.006" even on a std engine...

Edited by ozz1, 10 November 2016 - 02:08 PM.

[pete l]

Get it under load as soon as you start it

 

Why is this ?

[Midas Mk1]

 

Get it under load as soon as you start it

 

Why is this ?

 

Bed the rings in with the bores, so they dont polish and not fully seal. 

 

Best to load it up, have a google for the hard run in method. 

[pete l]

I always thought a newly rebuilt engine should be left on a high tickover for 20 minutes to bed in the cam. never heard this about the bores.

[Magneto]

I've just done this on my 1275 engine. After watching a few tutorials I got the cheapest honing tool I could find off ebay and had a go using engine oil and WD40 as a lube. I ended up with the cross-hatched pattern, but not quite as neat as a machine honed bore, but an happy with the results. Checked the gaps on new rings and they were bang on so with a little careful running in they should be fine. I spent about 30 seconds on each bore and the honing stones had completely worn away, they were very cheap after all.

 

There are still a couple of marks but they passed the finger nail test.

 

 

You really have little to no crosshatch pattern here......the marks should be close to a 45* angle to each other. I don't think you can move your arms fast enough to do that unless you  have a really slow turning drill, that's why you have it done by a machine shop. But that said for a street motor it will probably run just fine.....be sure to clean the bores properly, soap and water wash, then oil down and run a clean white rag thru the bores, if you get any dark marks on the rag, oil it up and keep cleaning till the rag comes back clean.

[panky]

Hi thanks for the advice. I gave the bores a good scrubbing with a strong detergent and a toilet brush (new) and then attacked it with the jet washer. No sign of any residue afterwards.

[Spider]

 

I've just done this on my 1275 engine. After watching a few tutorials I got the cheapest honing tool I could find off ebay and had a go using engine oil and WD40 as a lube. I ended up with the cross-hatched pattern, but not quite as neat as a machine honed bore, but an happy with the results. Checked the gaps on new rings and they were bang on so with a little careful running in they should be fine. I spent about 30 seconds on each bore and the honing stones had completely worn away, they were very cheap after all.

 

There are still a couple of marks but they passed the finger nail test.

 

 

You really have little to no crosshatch pattern here......the marks should be close to a 45* angle to each other. I don't think you can move your arms fast enough to do that unless you  have a really slow turning drill, that's why you have it done by a machine shop. But that said for a street motor it will probably run just fine.....be sure to clean the bores properly, soap and water wash, then oil down and run a clean white rag thru the bores, if you get any dark marks on the rag, oil it up and keep cleaning till the rag comes back clean.

 

 

Not just (lack of) crosshatch, though that could be just the way it photographs but also what's the finish?

 

Seriously and sorry if I get you nose out of joint here, there's just no way that you'll get a suitable finish from one of those tools and just from a single grade of honing stones. Respectfully, there's a LOT to honing and you're just never going to be able to pick up what really is needed from a 5 minute youtube clip.

 

It'll work and not burn too much oil for a while, but it'll have a short life.

 

Considering the effort and cash involved, just spend a few extra bob and do it right from the outset. I see your heart's in the right place, just a little misguided.