Primary Side

I have noticed that some suppliers sell a chain tensioner with the composition rubber on the WRONG side; that is, for Triumph 500s. The part number for this is 70-6283. If you look at the picture the blade rubber is not set in the center but rather to one side. The 650 number is 70-6061. The slot in the blade HAS to be to the out side for the adjuster to be lined up with the trunnion and drain hole. Using the wrong part will bind the adjuster and the chain will not be supported correctly! Send it back.


Very important to line up the transmission sprockets. If you can get it real even with everything set up as it should be it is good to go. The spec is .004 clearance and the chainwheel moves that when running sometimes. A temporary spacer can be seen between the clutch nut and washer to make it easy to get the nut on and off.


A new chain and gears make it a very tight set up. If you get to the point you want to try just to put the rollers in individually, be careful. Put a rag under the chainwheel. If you drop a roller and it goes into a hole it gets behind the wheel and you have to start over. Don't ask me how I know this. It is easy this way with tweezers.


This picture is here to show you what new springs look like when you buy them from US dealers. The original springs are hard to find. They are 1 and 13/16 inches. This is important. US dealers sell a lot of springs that are 1 and 3/4 or otherwise. I've had so many clutch problems that were solved by getting the right spring length and coil thickness and replacing them when the clutch acts up. TMS Nottingham has them listed as 57-1830. Always use a new star washer on the alternator, 21-7024.


Make yourself a special tool so that you do not have to open the drain to find out how much ATF fluid you have in the primary. Open it to adjust only. TR6Ray has a section about this. Theoretically, a mark at the chain should be about 310 cc, which is about right. That is at the bottom of the mark on my tool.

Courtesy of TR6Ray
Courtesy of TR6Ray

I was putting the cover on the primary and ran into a hole with something in it. This picture is not of a tap. I was using the tap when it broke off in the hole. Well, there is a moment when your heart rate goes up since the engine is already in the frame. This picture is of a very handy tool: a broken tap remover tool bringing the broke tap out. . This is called Walton Company 1/4" 4-flute tap extractor, No. 10254. $12 at Brownell's Guns.


This tool removed it in a minute. If you look closely you can see some little black lines. These are sliders.


The little black lines are four pieces of metal that go into the flutes of the tap and surround it. They are extended in this picture. The larger round piece is to slide over the black sliders after they are in the flutes of the broken tap. It is necessary to push this up to the hole so that there is shearing force applied to the tap not bending force. Shearing force left and right is what moves the tap. Read the directions: Magic!!!


A wire brush is so handy for cleaning these grooves. (with some brake cleaner)


I found the nut from the stud of the frame to the engine plate had damaged the stud. These tools work. That stud can be difficult to remove. Save the frame. Use 100 ft/lbs of torque on that nut.

Tap and Die

The cover went on like it was meant to. Don't forget the 10 ft.lbs. on those hex nuts.


Primary side is done. Starting to feel it. Want to ride.


These are the gallery of pictures. Click one. At the bottom of the pics will be a menu to bring you back here or go to the Homepage. Later in a restoration they may be worthwhile. Marino at MAP Cycles sells a double lipped front engine seal. I will try this at some point but for now I will put the spring out. I do not want ATF fluid mixing with the oil.

I tested the seal with two .003 shims in place behind the sprocket and a .006 shim from McMaster Carr oversized 1-3/8" ID to get past the radius behind the bearing to help centralize the connecting rods. The seal has the spring out. Below, the second picture with Torco Red Assembly lube shows this seal rides 1/16 inch from the chamfer. I was concerned about this but talking with Tom Gunn, he reassured me that it is a tough seal and should do fine.


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