Taking the Triumph Bonneville 865cc Engine to an 1100cc Beast!With the help of Bill Gately of Bonneville Performance!
I had over 63,000 miles on my 2008 Bonneville 865cc engine and it needed a valve job. So, instead of doing that only, I decided to send the entire engine to Bill Gately of Bonneville Performance, for a complete engine overhaul and upgrade modification! My final engine will have the same spec’s as the BP 1100cc crate engine, including:
- New bearings
- New oil pump
- Billet cylinders with Nikasil lining
- BP performance head porting with BP valve train
- BP Cams
- Crankshaft dynamically balanced
- All paper and MLS gaskets
The modified engine, along with the twin Mikuni HSR42 carbs and the BP 2 into 1 Exhaust system should produce approximately 94 HP and 76 ft. lbs. of torque. Bill also had a number of the engine covers powder-coated satin black for me.
Step 1 – Remove stock 865cc engine from 2008 Bonneville frame
This is easier said than done. You basically have to take the motorcycle apart! I followed the steps in my Haynes manual to remove all the parts that connect to the engine including exhaust system, oil cooler, carbs, electrical system wires and components, and subframe members.
I supported the rear of the bike from a garage joists with 2 adjustable tie-down straps. With the front tire in a floor carrier, the frame is stable and suspended.
STEP 2 – Prepare engine for shipping in a crate
Bill Gately suggested that I contact Johnny Scheff at Motoworks Chicago to see if he had an extra Triumph engine shipping frame. These are angle iron frames that Triumph uses to ship its engines to dealers. As it turned out, Johnny did and was kind enough to let me borrow it.
Saturday, January 3, 2014 Update – Engine removal and mounting to shipping frame
We had a little trouble with getting the engine to drop from the frame, but once I removed a couple more brace pieces around the lower exhaust mounts, things freed up and we were able to slide the engine down free of the frame and then sideways on the floor jack. Then we were able to pick up the engine (it weighs about 165 lbs) and mount it on the bright yellow Triumph engine shipping frame.
January 4, 2014 Update – Building the Shipping Crate
Here are a series of photos of the process of building the shipping crate around the 865cc engine on a shipping stand. I purchased 2 sheets of 1/2″ x 4′ x 8′ plywood, (4) 2x2x8 ft., (1) 2x4x8, (1) 1x3x8 and (1) 1x4x8 plus misc screws, etc. for about $75 at Home Depot.
Next, I added the rest of the framing and the end panels. I also put a 2×4 brace across the interior for extra support and engine protection.
Step 3 – Engine Rebuild Process
January 15, 2015 – Arrival at Bonneville Performance
I am pleased to share that my 865cc engine crate arrived safely at Bonneville Performance via Pilot Freight on Thursday, January 15, 2015. The crate was in good shape with no signs of stress or damage. Bill Gately, owner of Bonneville Performance was able to disassemble the crate, lift the engine off the skid and get it setup in his shop for tear down. Thanks for the photos, Bill!
I have been told by Bill that he will tear the engine down and then:
- Crank to House of Balance in Baltimore, MD
- Upper crankcase to Daytona Auto Machine shop in Daytona Beach for boring
- Cams to WEB Cam racing cams in Riverside, CA
- Billet Cylinders to Daytona Auto Machine shop for boring and sleeves insertion – then to Millennium Technologies for Nikasil in Plymouth, WI
- Cylinder head and manifolds to be ported and then to Daytona Auto Machine shop for the valve job
- Everything else to be cleaned and inspected
There is a 3-week wait on the crank and cams before they are returned to Bonneville Performance which puts the reassembly starting around the week of February 9, 2015. I am assuming I won’t see the engine back until some time in March.
Update February 17, 2015
I spoke to Bill yesterday and learned that my engine parts are in the process of coming back to him from the various shops.
My engine should be looking like this fairly soon except it will have satin black powder-coating instead of glossy.
April 28, 2015 Update – Engine Crankcase Reassembly
I heard today that my 1100cc crate engine rebuild is moving along nicely. Here are photos of the parts back from various machine shops and parts vendors ready for reassembly.
May 2, 2015 Update – Engine Reassembly, Cylinders, Head, Cams and Covers
Bill sent these photos to me today, to let me know that all he has left to do is set the valve clearances, cam timing, and button up the timing cover and cam cover – then into the crate for the Monday, May 4, 2015 pickup!
May 12, 2015
Always good to arrive home from work and be greeted by boxes of performance parts from Bonneville Performance! I received my Bonneville Performance Stainless Steel 2 into 1 Exhaust System that I will be using with my rebuilt Bonneville Performance 1100cc Triumph Twin engine. Also arrived was the Bonneville Performance Crankcase Oil Breather Canister Kit for the same engine.
As soon as some correct size valve shims arrive, Bill will finish up my final engine adjustments and ship it to me!
May 2015 Update
I am happy to report that my engine rebuild has been completed by Bill Gately at Bonneville Performance! Now, the planning begins for how we will put it all back together!
December 2015 Update
The 2008 Bonneville frame is going back together in preparation for a road trip down to Bonneville Performance in January 2016 to be reunited with the new 1100cc engine! The task today was to install new All Balls Steering Stem Bearing Kit 22-1020 in the head and then install the upper and lower yoke assembly. The new replacement bearings are roller bearings that replace the less desirable and less reliable ball bearings installed at the factory. I followed the instructions in the Haynes manual to remove the old bearings, and press in the new sleeves and bearings without the use of a machine press.
January 1, 2016 Update
In preparation for my trip to Bonneville Performance later this month, I am using my holiday weekend to get more of the frame and parts ready for the trip and final reassembly. This morning I trimmed 3/4″ off the sides of the rear fender, and 1/4″ off the sides of the front fender. While the Bonnie is apart, I plan to shoot some new coats of Eastwood Rat Rod Satin Black Paint (Item #21857ZP) on these parts: fenders, chain guard, side covers, front sprocket cover, and seat cover. I am considering also shooting the swing arm and the gas tank (not pictured) but leaving the frame in the original factory black.
Week of January 25-29, 2016
I loaded up my 2008 Bonneville in my 1993 Chevy pickup and headed down south to Bonneville Performance to install and dial in the 1100cc rebuilt engine.
After arriving at Bonneville Performance, we unloaded the bike, put it on a work stand in the shop, and began the process of installing the engine into the frame.
January 29, 2016 – First ride with the 1100cc engine!
Having completed the assembly of the 1100cc Bonneville Performance twin back into my 2008 Bonneville frame, heat cycling the engine and doing the final oil change to synthetic Castrol racing oil, I was able to take the bike out for its first spin. I took it for few laps around the streets near Bonneville Performance. A short GoPro video clip is below.
All I can say is… Wow! Amazing! Incredible! How else can I describe the increase in performance? The most noticeable change is the instant response to the throttle and the torque! I am sure a wheelie would be no problem… and that fact that is a bit scary!
February 1, 2016 Update
A little over a year since I began the project, I arrived back home with a fully functional 2008 Bonneville with a high-performance 1100cc engine. A couple of friends helped me unload the bike at home, and it is now safe and sound in my garage.
It still being winter in Chicago, I have a number of smaller projects, modifications and improvements to make to the bike to get it ready to ride in the Spring, including:
- Install Sato Racing rearsets
- Install 520 chain and sprocket conversion
- Final paint color sanding and buffing, including gas tank
- New custom badges
- Replace and improve fuel lines – Tygon
- Install shorter K&N air filter pods
- New handlebar grips
- New front gaiters
- Sort out front brake master cylinder mushiness
- Sort out rear shock performance issues
- Consider changing rear wheel from 17″ to 18″ dia. to improve handling and suspension performance
May 22, 2016 Update – Dyno Results
I have been able to complete the items on the list above except for the last one, which I will wait another year to do. I am also happy to report that I had a chance to put the Bonneville on a Dyno and had some great results, as shown below.
The outcome is basically 92 HP and 72 ft. lbs. of torque with a power curve that just keeps building, at least all the way to 115 MPH! This matches my riding experience where I have not yet experienced the bike flattening out… at all, at any speed, in any gear. It is truly amazing to ride!
Additional Work Done Since 2016
In the months and years since I completed this project with Bonneville Performance, I have made some additional changes and upgrades.
After more discussion with Bill Gately regarding the initial dyno results I got, he recommended that I go with the Mikuni HSR45’s for additional intake capacity. These carbs are 3mm larger in diameter than the HSR42’s, but otherwise have the same housing and connections. I went ahead and made that swap and have definitely noticed an improvement in power.
In 2019, Bill told me that he had entered into an agreement with Triumph Twin Power (in the UK) to make a custom CDI unit for his engines. I purchased the Fire Starter with the custom map for the BP 1100cc engine (https://www.triumphtwinpower.com/fire-starter-performance-igniter-unit.php). Wow! What a fantastic improvement that made!
I also upgraded the headlight to an LED unit so I can see better at dusk or at night, or during rain. It really makes a huge difference! This is the unit I purchased: Liteway Headlight. It fit right inside my stock headlamp bucket in place of the original and plugged right into my three-prong connector.
I have also purchased additional diffuser discs for the Supertrapp muffler to tune the exhaust a bit more.
A recent photo that was taken on a ride in March 2020, here in Southwestern Wisconsin.