Engine & bike Tips:

This page is my meager effort to shed a little light on how your old Triumph's engine works and my problem areas I encountered durring my build. First is a little about how the engine works because you need to have a basic understanding of how it works in order to build and maintain one. The second part below are a few notes on trouble areas you may encounter wile building your bike. >

The 650 unit Twin is a wonderful engine to cut your teeth on and fairly easy to rebuild with the resources I suggested. The Triumph Twin engine is really a remarkable piece of British engineering and quite reliable if properly maintained. One of the main things to understand about any of these old engines is they vibrate a lot more than your super balanced modern engines and routine inspection is a must. So get yourself into the habit of inspection and routine maintenance as outlined in your manual and you will experience a much higher level of fun with your machine. Especially if you drive a hardtail like I do!

Triumph build notes:

Connecting rods & Crank,

Connecting rods, Crank and bearings will come into play wile building your bike. This is a very important part of building a strong reliable engine. You can't afford to make any mistakes in this area. First you'll need to determine what needs to be done in regurds to your rods and the condition of your crank. If your lucky, your crank will be in good condition with only normal wear to your bearings and your crank journals will be within spec and only a new set of standard shells will be needed and small end bushings. Unfortunately this isn't always the case. In my particular scenario, my crank was in need of a .10 under regrind in order to accept .10 over shells to come into mfg required specs for my crank and shells. The crank had wore to just below being able to accept standard size shells and if fit they would have surely caused a loss in oil pressure and possibly failed early and jeopardized the integrity of my rods,crank and everything else involved. A good set of calipers is needed to check your crank journals but better yet and easier is to just bring your crank and rods to a reliable machine shop that is familiar with British bikes and they can asses what needs to be done. They can also check your rods and install the small end bushings which are not as easy as some may say to do on your own. I did my own small end bushings and it was a pain. Pressing them in isn't hard with the right tool but reaming them to fit your wrist pin with a hand reamer is not so cut and dry. I went through two sets of bushings doing it myself. The first set I damaged with the reamer by causing what is known as reamer chatter. This is easy to do with such a soft metal as the bronze used in small end bushings. You can try it if you like but chances are you'll have a serious learning experience like I did. My advise is to have the shop do it.

Oil Lines,

People tend to think inside the box about oil lines on Triumphs. Lets face it, if it works why change it? I'll tell you why- because sometimes things don't fit in the box and my build made this evident. when I built my bike, I wanted it to look like it might have been built in the past. So I picked a oil filter which is a reproduction of a early HD filter that might have been lying around back in 60-70s if you were a guy building a bike, It fit and looked good in a certain area of the bike. This positioning of the filter didn't alow me the luxery of keeping with the traditional Triumph configuration which dictates that the main line flows directly to the tank with the rocker feed branching off and I decided I wanted to use polished stainless 1/4" lines and Swagelok fittings. Well to get this all to fit my tee ended up branching off the oil tank at 90 deg and strait flow headed to the rocker feed. Well after trial and error I figured out that the flow was much more moving to the rockers than heading to the tank which forced me to restrict the flow to the rockers other than the traditional ristriction which is at the tank so oil will flow to the rockers. Mine is backasswards but works. My point is that if you come up with differant layouts on your bike and find yourself in a corner, understanding how it works and whats needed will open the door for new types of oil feed systems that work.

Transmision

Indexing and instalation of the sping steel indexer

In the 70s Triumph came out with a new type of indexer replacing the old plunger style indexer.The problem is that in the manual it refers to the old plunger indexer which dictates that you put the cam plate in a position that doesn't work for the spring steel indexer unless your very lucky. The spring steel indexer isn't hard once you figure it out and figuring it out is hard. The way to do it with the spring steel indexer is to engage it wile the cam is in it's 4th gear position and the shifting gear that engages the cam plates gear also has to be in it's furthest fourth gear position so it works throughout it's range as well. Below is some pics to show how this works. Once learned it is easy and you don't have to go through what some of us have.