Honda-SOHC

Is it possible that you smell unburnt petrol as the oil has fouled up the plugs first - cause oil deposits on the plugs leading to unburnt petrol afterwards. Often you can see no blue smoke in oil burners.

Where rings have been replaced rather than a rebore with some glaze breaking  I suspect some running in might be needed before worring about  plug colours.

As an aside my 400 that was rebored by Graham has only covered some 230 odd miles - unless it starts misfiring I will not check the plug colours until it has covered about 600 miles. My idle speed is good and even - to date only bench synched the carbs as it's now running so well after my initial mistake on the plug connections when it was a two cylinder bike for a while!

Quote from: McCabe-Thiele (Ted) on April 26, 2024, 03:11:56 PM

I've noticed quite a few Websites where phone numbers, actual postal address are missing as well as a lack of e-mail address.
Some that have them keep them well hidden it seems with lots of navigation needed.

Companies Act 2006.

If you are a limited company in the UK you must put (at least) your registered address on your website.


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That address is often one of a row of brass plaques at an office full of letter boxes!

I'll put it out there, plug fouling can also be caused by oil burning.
Worn rings or valve stem seals/ guide wear.

My understanding of spark plug technology  is they are designed to be  self cleaning at higher revs/temperatures - obviously there is a limit to this function so if the mixture is overly rich right through the range they will soot up.

I suspect throttle blipping was something we used to do to keep the plugs from sooting up at idle to make a clean getaway.

My experience primarily with cars using carbs is that a vehicle used for mostly short journey work fitted with the manufacturers standard plugs would foul up badly needing a good run to clear the carbon deposits.

I particularly remember a disabled customer who ran an Automatic Opel Commodore 2.5 GS (1974) from his home to work a  distance of less than a mile. On collecting his Opel from Ashbourne it would not exceeed 45-50 mph flat out. During the course of the journey to our service department  in Burton the top speed would slowly improve until it would reach 60-65 mph. After a service the car would drive like it should for a 2.5 litre straight six.

Fitting a different plug type to cope with the short journey used mostly on auto choke was not an option as the customer would drive to Scotland a few times a year where he had family. In reality he wouid have been better driving a car with a much smaller engine.

I've noticed quite a few Websites where phone numbers, actual postal address are missing as well as a lack of e-mail address.
Some that have them keep them well hidden it seems with lots of navigation needed.

Result - you can't sometimes beat brute thuggery.👍👍👍

I'm with you on this Ash I'm a Leftie.

I only have one that I bought for a particular use - flank drive ring spanner they avoid rounding off bolt heads.

I would like a set but price is daft money - this is a used set!

.https://www.ebay.co.uk/itm/135029750512?itmmeta=01HW7PEYR3SW9R5QY1RJ5Y9E1Y&hash=item1f70667af0:g:yigAAOSwtaxl72oo&itmprp=enc%3AAQAJAAAA0LTuhXps%2FQn%2BbiSNiXJ0hUWnBSEYr2K7Lxk%2BcrhHN2qBAJb4rYBB9mcRiUWa8GgumqhozgP7KaziEG2slFzirrQWDwfDQZO1jTgmb958CcRaLmLWeUUokCrQqRqgaItU83EiOw0rFsx7J2fe2gUI4Tp5Csn1D0lWhCCuoboXaI%2FpjJ%2FEpjFljNswFpQ6pLrbUzSjJtPZhKlBJoyUgutom2BQsGolB%2FHvVL%2FpuVGA%2FLhg7UPQCe4egLPQ6R6uNv%2FDWn5%2FFHIK92TFiNclBHrZRsI%3D%7Ctkp%3ABk9SR5bsu_bhYw