Triumph Bonneville DIY Oil Pressure Gauge

I want to add an oil pressure gauge for my bonnie. A kit is available from British Customs, but the $150 price tag is too much for me to justify buying one. I figured someone must have had done this already. I mean its a gauge and a cable, right?

DIY Oil Gauge Attached to Right Manifold

As most of my bonnie-related searches, Google, takes me to Triumprat.net. User tooblekain has written a step by step DIY that includes a shopping list. I pretty much used his shopping list with a couple of differences.

I wanted to be as close to what British Customs offers. I found the same brand of gauge that they used in eBay for less than $20. That is at least 50% on what I've seen other gauges sell for. I used a straight AN3/NPT adapter instead of a right-angle one used by tooblekain.

Item	Description	Merchant	Price
Marshall CW00100	Gauge white face 1.6" (40mm) 1/8" NPT center back connector 0-100 PSI	eBay	$18.99
Russell Universal Brake Line Assemblies 656022	12" Straight cable -3AN to -3AN male	Summit Racing	$19.97
Russell Brake Adapter Fittings R40508	10MM x 1.25" double banjo bolt with 3 stainless steel washers	Summit Racing	$8.95
Russell Brake Adapter Fittings R4051C	10MM x -3AN male 90 degrees	Summit Racing	$6.95
Earl's Performance Pressure Gauge Adapters 968703ERL	Straight pressure gauge adapter steel AN3 male, 1/8 Inch NPT female	Summit Racing	$3.97

That is a grand total of $58.83. That is more like it. The other miscellaneous items that were needed I found at home:

• Teflon tape
• M10 washer
• Copper washer
• Bracket

Bracket

The longest part of the process is making the bracket. I had to bend it just right and shape one end so that it fits where it connects to the manifold. I also painted it because I ruined the plating while shaping and filing it.

Homemade bracket

Attach Oil Pressure Gauge Adapter on to Cable

The adapter is needed because the pressure gauge uses a 1/8"NPT male connector. The cable uses a 3AN female connector. Use plumbers teflon tape when attaching the adapter to the cable.

Cable with adapter attached

Create Bracket and Gauge Assembly

You'll need the M10 washer and copper washer to put together the gauge bracket assembly. Insert the back of the gauge into the M10 washer. Insert the bracket next. Follow this with the copper washer. Finally, wrap the gauge connector with some plumber's teflon tape and screw on the cable (adapter side). Do not over tighten. You may need to make adjustments later.

Attach Bracket and Gauge Assembly to Manifold

The bracket assembly will attach to the right manifold. Remove the right bolt from the manifold. Attach the bracket into the manifold and insert the bolt back and tighten.

Attach New Banjo Bolt

The original banjo bolt must be removed. It's located right at the top of the engine chassis below the carbs. There should be two copper crush washers that comes along with it after removal.

The double-banjo comes with three washers. Insert a washer into the banjo first. Insert the 10mm banjo adapter followed by a washer. Finally attach the oil line banjo and the last washer. I found it easy by laying the last washer on the engine chassis and putting the original oil line banjo on top of it. I then lined up the banjo bolt (with the washer and banjo adapter) and inserted it down into the original oil line banjo. Tighten the banjo bolt afterwards.

Attach Gauge to Banjo

This step is a simple matter of lining up gauge cable on top of the banjo adapter. Tighten the cable into the adapter securely but do not over tighten.

At this point, you should tighten and align the gauge on the bracket as you see fit.

Post Install Observations

While my bike is warming up the PSI is around 55.

55-60 PSI During Warm Up

After riding for a while, during idle the PSI stays around 25-30.

25-30 PSI During Idle After Warm Up

 This project is very easy and worthwhile.