Compression tester adapters
 

Hi all

I've been meaning to do a compression check on the bikes recently, and after a search in the shed I have found a Gunson Hi-Gauge compression tester which I last used about 10 years ago. It has an 18mm thread on the end, which is no use for bikes. The more expensive Gunson gauges come with a set of adapters to fit 14/12/10 mm sparking plugs. Does anyone know of anywhere I can buy these adapters separately (or anything similar)? They aren't listed on the Gunson website, except as part of the bigger kit.

Am I right in thinking the NGK DPR8EA-9 has a 12mm thread?

Cheers

Got my adaptor on ebay although admitedly not used it yet. Lots of different sizes.:thumbup1:

n

Hi Richard,

The first coding letter 'D' identifies the plug as being 12mm (B=14mm; C=10mm).

Try this link for the adapter: Gunson | G4055B | Hi-Gauge Adaptor Kit 12mm . Looks like it is the same adapter as for ColorTune (useful!) - & you may find it at a local Motor Factors?

Good luck,
Geoff

None on eBay when I looked :( I'll keep looking, thanks.

Geoff, thanks for confirming the size. I found a website that gave this info, but it seemed illogical - A is 18, B is 14, then C is 10 and D 12. I thought I'd check! I asked about an adapter in Halfords, but they told me it was only available as part of the Colortune kit (which I already have but no adapter). What I'd really like is a kit that includes 12 and 10mm adapters, so that I can do the same with the Honda.

Sadly, our only motor factors closed a few years ago. Now all we have is Halfrauds :(

Hi Richard,

I am not sure I understand fully.

If you go to the link I provided, there is a hot-spot called "Find Online Retailer" and you will see several places which have both the 12mm and 10mm adapters for sale at reasonable prices.
One such place is here: Compression

Also both the 12mm & 10mm Adapters appear to be on Ebay (perhaps at a higher price?):
Gunson G4055B Compression Tester Adaptor Kit 14MM-12MM on eBay (end time 20-Nov-09 11:10:56 GMT)
Gunson G4055A 10mm Compression Tester Adaptor Kit on eBay (end time 07-Nov-09 19:00:16 GMT)

Ciao,
Geoff

I tried to use a compression tester the one I had needed an adaptor to fit the plug hole but when the adapter was fitted it made the compression tester to long so when you tried to screw it into the plug hole it was hitting the frame.
I cant rember if this was on my XT or TTR
I also heard it is quite difficult to test the compression on a single cylinder with kickstart.

Geoff

Thanks for the link. I didn't find that when I searched the website before. At least, nothing came up with the search function. Unfortunately, my nearest stockist is in Aberystwyth, over 60 miles away! Good to know Gunson do both 10 and 12mm - I can search with the product numbers and find something online, I hope.

Bolla

Some testers have long probes, as this seems to be easier to use when testing a car engine. The Gunson gauge has a flexible hose with only a couple of inches rigid at the business end, so it should be OK for a bike.