Stripping Down My Barn Find Triumph T140 Bonneville to Remove Cylinder Head | 02

In this episode I am hoping to remove the cylinder head from my 1975 Triumph Bonneville T140V. I have just bought this as a project bike, and rather than just trying to start the engine I want to assess what condition it is in.

Here are some of the tools I am going to be using for this bike:
Imperial Combination Spanner Set: https://ebay.us/gYz85M
Imperial 1/2inch Socket set: https://ebay.us/jylH05
Imperial Allen Hex Bit Sockets: https://ebay.us/iFV0OQ

This bike is an import from the USA, and has probably not been ridden for over 30 years. Some parts of it seem in really good condition considering the lack of use, such as the outside of the engine and the front forks and wheel. However some parts look quite ropey, and have a lot of rust, the back of the frame and the rear wheel and brakes.

I got the bike registered within 4 weeks. I explained this in an earlier video we have on the channel which you can watch here:    • How To Fill In A V55/5 Form - Importi...  

The engine turns over and the outside of it looks to be quite clean. Looking around it, it appears to have had some work on it, there seems to be a new(ish) base gasket, the case screws have been replaced with Allen headed screws, and the head studs seem to be stainless steel.

The carburettors on these bikes always seem to corrode badly when left, but the carbs on this bike are in quite clean condition. So it looks like some care and attention was put into the bike before it was laid up.

The clocks have been reset and now only read 342 miles. I am hoping that this indicates that the engine was refreshed 342 miles ago. But this is likely to be more than 3 decades ago as well, and time has taken its toll on some parts of the bike.

Unlike the CB750s I have been working on recently the cylinder should be removable without taking the engine out of the frame. It will also make it a bit lighter, so when the engine is going to be removed it should be easier. To remove the cylinder head a lot of other parts need to be removed first.

Obviously the tank needs to come off, which is basically held on by one bolt from the top of the tank. Which is quite easy to do once you have disconnected the fuel pipes. The exhaust and air filters need removing too.

The exhaust came off really easily. It is a push in type and didn't appear to have any sealant holding it in. It is a two into one exhaust and although the chrome has got some pitting, overall it would probably clean up. I am planning to get a new exhaust for this bike, so I might convert the head to have the exhaust stubs fitted that allow the use of the older style of pipes. These are also supposed to be easier to seal

The air filters were quite dirty on both sides. By that I mean where the air comes in and then where the air goes after it is filtered. I don't think the bike has been run like this. I think it more likely that this from the bike having been pressure washed before shipping with the carb side of the airbox not sealed.

Once you have got to this point, with the tank, exhausts and air filter off, the next step is to remove the rocker boxes. There is a head steady between the rockers and the frame that needs removing. It is one of those things that seems really fiddly to remove and then just about falls off. The nuts holding this one had the worst corrosion of anything on the bike, but still came undone ok.

With the rocker covers off, it is very easy to get to the nuts on the head studs. Usually the outer four are bolts that screw into the block, but they have been replaced with stainless studs. There are some allen head nuts for 4 of the head fasteners, but they all came undone quite easily.

It was at this point that I came against my first problem, and it is quite a big one. I was hoping that with a bit of tapping with a hammer and piece of wood that the head would come loose. Unfortunately it is stuck solid.

I used heat tapping with bigger and bigger hammers, and I did try to remove the out studs, using two nuts, but they are not for moving. I kept leaving the job for a couple of days with everything doused in penetrating oil, and coming back and having another go. Although I did find an old T120 for stantion that fitted into the exhaust port, I didn't go mad with it. I just used it to apply some pressure while I tapped other parts of the head.After 3 or 4 different attempts I have come to the conclusion that I may have to try some different methods with the engine removed.

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