Shovelhead 4-speed overhaul part #2

Now that we have the primary drive components out of the way we can proceed with the removal of the inner primary housing. But before we can remove the inner housing we need to get some stuff out of the way.

First I disconnected the wires from the solenoid and got reminded that I had forgotten to disconnect and remove the battery. (dumbass!) So always start by disconnecting the battery! (I did disconnect the spark plug wires though 🙂 )

After disconnecting and removing the battery (we need it out of the way anyway to get better clearance when we need to remove the starter motor later on) I removed the solenoid from the primary housing. To get the starter gear lever and the starter shaft out, we need to unscrew the pivot bolt, that holds the the starter gear lever, from the top of the housing. This bolt can be quite tight and there is almost no room because of the oil tank….so if you hadn’t guessed by now…..time to drain the oil tank and remove it from the frame!

After draining the oil from the tank, I disconnected the oil feed and return lines, removed the nuts from the mounting studs and lifted the oil tank out of the frame. (inspect the mounting stud rubbers and order new ones if needed!)

With the oil tank out of the way I could remove the pivot bolt and take out the gear lever and starter shaft assembly.

Shovelhead solenoid plunger, starter gear lever and starter shaft assembly

The front inner mounting bolts for the primary are secured with a safety wire, after removing the steel wire, I removed the upper and lower bolt (the center bolt doesn’t go into the crankcase), then removed the 2 rear bolts and the front 2 allen head bolts on the outside of the housing. (which were metric bolts in my case, so I first had to get a set of metric allen keys :S)

But wait…I’m forgetting something…. The starter motor is still bolted to the back of the primary 🙂

After disconnecting the wires from the starter motor, (label them! Especially if all your wires are the same shade of black, like mine :S) removed the chrome bracket from the back of the starter motor on the right side of the bike. Now it was time to unscrew the 2 studs/bolts that run through the starter motor and into the starter shaft housing on the back of the primary. (carefully lift it out as a unit, make sure you don’t pull the starter motor apart!)

Now I was finally able to get the primary out of the way and get on with removal of the gearbox 🙂

Shovelhead with primary housing removed

As you can see from the picture I try to make a habit out of screwing the bolts back where they came from. This can save you a lot of trouble with the reassembly!

More to come in Part #3!

Shovelhead 4-speed overhaul part #1

Until recently my 1982 Shovelhead didn’t leak a drop of oil. One of the main issues with these bikes (in regards to marking it’s territory) is a leaking primary, but mine was sealed great with the help of James Gaskets and some blue silicon. Another source for oil leakage is the oil seal on the mainshaft of the transmission. In my case this turned out to be the cause of my Shovel marking it’s territory. It started with a small drop every now and then but it got worse rather quick.

It can be difficult to pinpoint the exact source of the leakage, because the bottom of the engine, primary and tranny is often covered in lot’s of grease and dirt. So I started by cleaning the bottom of the engine and transmission with some brakecleaner, and the next morning I could clearly see the oil trail leading from behind the transmission sprocket to the bottom mounting bolts. Time to take it apart!

Before you can get the transmission out you need to get some stuff out of the way, the most obvious being the primary drive. After I drained the oil from the primary, I removed the primary cover and ran into the first challenge: the clutch.

A few years ago I replaced my clutch with a Barnett Scorpion clutch (no more slipping!), but to get the clutch hub of the mainshaft I needed two specific tools from Barnett, a Scorpion Clutch Lock Plate and a Scorpion Clutch Hub Puller.

Barnett Clutch hub puller and lock plate

First thing was to get the clutch hub nut loose (left hand thread! so turn clockwise to loosen!). Before you can unscrew this nut you’ll need to lock both the primary and the clutch. I used a piece of steel bar and rounded both ends using a file, stuck this between the crankshaft sprocket and the clutch shell to prevent the primary from spinning. I then used the clutch locking plate to lock the inner clutch hub to the clutch outer shell. (if you have some old clutch plates lying around you could weld 2 together to make your own locking plate)

Shovelhead primary lock bar

The clutch hub nut can be very tight, so I heated it up first using a paint stripper and then, using a 1 1/8″ socket and a long steel rod over the wrench, I removed the nut. (I guess you could use an impact wrench too) Because the mainshaft is tapered, the clutch hub will be very tight, that’s why you need the puller. Be sure you screw the clutch nut back on the mainshaft for 5 or 6 turns and put a washer over the nut before you attach the puller. If you don’t, the puller center bolt will push against your clutch pushrod and you’ll brake shit. (trust me!)

Before you can remove the primary drive as a whole, you’ll need to remove the compensating sprocket from the crankshaft. This is normal right-hand thread and it takes a 1 1/2″ socket. I know some people use an impact wrench to remove the compensating sprocket, but I would personally recommend against that because there’s a risk of breaking loose the magnets on the rotor, and then you’ll have a whole new problem (especially if it goes unnoticed). Finally, loosen the primary chain tensioner and you can take out the complete primary drive.

Shovelhead with primary drive removed.

More in part #2!

1957 BSA B31 Restoration

For the last couple of months my brother and I have been working on his 1957 BSA B31 motorcycle. Approximately every Tuesday night we gather at his place to work on the bike. We started by removing the wheels to have new rims, spokes and tires fitted and are currently working on the engine. The cilinder has been bored to 400CC and we’re about to reassemble the engine. After that we still need to strip the frame and give it a new layer of paint, after that we’ll reassemble the bike and fit a new Amal MK1 Concentric carburetor to replace the Amal Monobloc.

You can watch the photo-blog here:

Update: 15-may-2014

We have been working on the bike steadily for the past few months (almost every wednesday evening). The frame was recently powdercoated along with some custom fenders, engine mounting brackets and some other small parts. The cylinder was bored to approximately 400CC’s and a Honda piston was fitted too match the bore. We’ve begun reassembling the engine and tried to bolt on the cylinder head yesterday when we discovered that the firering (the protruding ring on top of the cylinder base) was higher than the depth of the corresponding groove in the cylinder head (am I still making sense?).

BSA B31 cylinder firering
BSA B31 cylinder firering, 3.2mm
Firering measures approximately 3.2mm
Firering measures approximately 3.2mm
Groove in cylinder head measures approximately 2.3mm
Groove in cylinder head measures approximately 2.3mm

So either we have the head machined or the ring on the cylinder skimmed….

Update: 22-sept-2014

Well, as it turned out, we were wrong in thinking that the fire ring on top of the cylinder barrel should stick all the way into the groove in the head. That ring and the corresponding groove actually form the mating surface. So we put a bit of coppergrease on it and reassembled the engine.

The engine is completely overhauled with new bearings and bored to 400CC’s. We also decided to invest in a more reliable oilpump made by ABSAF in Appingedam (Netherlands) and a new sump plate with magnetic drainplug by SRM Engineering.

Continue reading “1957 BSA B31 Restoration”