This year I bought a 81 FXB

Since the bike is new to me I have no idea of its service history. When it was revived before being sold to me, the shop replaced all fluids and rebuild the brakes and carb. The bike runs very well, to my untrained butt at least. Something is wrong with the ignition though as it does not have the typical idle lope, instead it kind of runs like a BMW... which is nice but it shouldnt.

This winter (which is no riding season here in Switzerland) I want to check the primay belt and have a look at the ignition.

I opened the ignition cover to find this:

Points, instead of the original electronic ignition. Notice how they are adjusted to full retard... plan is to measure the coil resistance and put a Dynatec in. I have not dug into it further yet but expect a bad advance unit.

I also opened the primary

To my untrained eye the belt looks to be OK, better than the one in my other Sturgis (from 1982). A bit loose though. Notice the warning label on the clutch 😁

about 1-1/4" play where it should be less than 1.

The clutch is funny in a sense that it sticks a lot. Whenever I downshift or roll to a stop in 1st I need to blip the throttle to kind of break the clutch loose. Upshifting seems to be fine. Plan is to open the clutch and clean the plates with brake cleaner ... ?

The big thing for me at the moment though is the nut on the crank. I read the official manual which says the bearing on the transmission shaft going into the primary should be greased every 10000 miles. If possible I want to see this bearing and maybe replace it with a SKF bearing that is greased for life, such that I dont need to worry about it anymore. Doing this will hinge on me being able to get the nut on the crankshaft off. I order the appropriate 1-3/4 socket for this. I want to try to block the primary from rotating using a block of wood, dont want to stick a t-shirt in the belt for fear of damaging it. I want to use a breaker bar instead of an air tool, for fear of rattling a magnet off in the generator.
Another thing is to check the current ignition timing before I remove the points, just to see where it is now. If I am ever strapped for a nice electronics project I may build a microprocessor with advance unit for it, using optical pickups, but for now want to get a dynatec... am not a big fan of the points as the timing between the cilinders depends on the height of the cam lobes being equal.

Sorry for the long rant, just wanted to make this post in the hope for answers to the questions that will inevatibly pop up...

 

hmmm, . . . thats the first time i ever heard any one talk about cam lobes when it comes to the points ignition , i do run points in my '83 wide glide with no problems. To check the timing & to static time your ignition you have to turn your engine over to front compression stroke, rotate it till just after the front intake push rod closes , then slowly continue till the advance timing mark on the fly wheel shows in the timing plug hole, turn the ignition switch on, then using a small test light you can then rotate the base plate & , turn the Advance unit to fully advanced then rotate the base plate until the test light turns on, tighten the point cover set screws , double check the adjustment & you should be done ! If It was my bike i would also check to see if it has the right coil, the electronic ignition & point ignition coils are not the same, they have different Ohms resistance, maybe the previous owner left the electronic ignition coil in it, also the point ignition spark plug wires are also different. As far as the Belt tension, in the service manual it describes how to tighten the front belt tension, its a little involved but maybe that could be your answer to your clutch problem ? Ok maybe this helps, let us know how it works out, best regards, Troy

 

to Bmp72 ,
you can get this points advance tool from W+W part # 98-021 to help static timing your points . . .works great for holding your points in advance position while you adjust your points base plate, good luck

 

while in a perfect world the 2 point contact lifts being exact is in play - but the shovel design is liken to a farm tractor left out in the weather 365 - so with that in mind it will not make a difference = even if they are different > reason - its not 180 firing and it also fires on the exhaust stroke at different times front verses rear - < the potato potato potato - sound

as far as the clutch goes its a paper product annelid to steel or alloys plates - over times and use before they wear thin they soak up oil vaper and or water moisture - this in turn runes the ability of it to perform up to speed - buy an alto red clutch disc set and the steels with out the ball and spring as they drag when things become worn and its what 50 plus years old - and a ram jet to hold the clutch drum in place so it does not walk out causing neutral issues

 

how old- miles - yrs is the belt. my belt is around 30 yrs old with not many miles on it and the last time i looked it still looked like new

 

The bike indicates 23000 km. It has been standing for roughly 20 years I think, the tires that were on it before had a datecode for 1997.

The reason I want to look at the ignition is that it does not make the potato potato sound, it runs very regular more like a fuel injected bike like a TC88. It does not occasionally miss like you would expect from a shovel. It can be heard on one of the last videos on my youtube channel (bmp72).

I am not planning to change out the clutch at this point, I got used to blipping the throttle to unstick it, and I find it gives character... I want to check it for wear (see if the rivets in the paper plates so not protrude) and just clean it.

 

ive found that spring tension makes a huge difference if adjusted right.less tension, easier shifting and finding neutral

 

advance unit behind points working, maybe stuck in advance after sitting for a long time? BTW everyone here recommends ditching the inline fuel filter as well

 

what is so bad about the fuel filter ?

 

This morning I went to take out the clutch

Based on Pacific Mikes video I was expecting rivets in the friction plates.
The last plate was stuck in the housing, had to pry it loose with a screwdriver



both the housing and the last friction plate were very greasy. With a bit of luck, degreasing the steel plates and housing, and wiping down the friction plates, will fix the sticky clutch issue.

To get the nut of the crankshaft off I want to try to make a tool that grabs the 6 blocks inside the clutch basket. I still have a 5mm thick aluminium plate and an L shaped bar I can cut fingers from. Is grabbing these blocks to block the clutch a valid way to loosen the nut on the crank ?