Carb stubs, 1000cc

[Packer]

Just doing a bit of cleaning and I discovered a bit of movement on the carb. Turns out that the stub is not tight in the head. Threads all look good and this may be what has been causing my issue with a faster tickover as the bike gets hot.

Should these be assembled dry or with some kind of sealant? Can't find mention of it in my manual.

 

[MickDB1]

Ive done mine with PTFE tape = others will come along with a posher option Kev
HTHY XXX

 

[Packer]

Thanks Mick.

It appeared to have been assembled dry so that is how I put it back together but tightened up obviously.

 

[Packer]

Just found an article on line. These stubs, described as spigots, were assembled at the factory into pre-machined cylinder heads heated to 212C using green Loctite which would obvioulsly not be possible on an assembled engine.

I am going to strip the carb back off and remove the spigot, make sure all threads are clean. I'll put the spigot in the freezer and use a heat gun to heat the alloy of the head Finally I'll apply red loctite to the threads and refit the spigot into the head screwing it up tightly. The www.bmwmotorcycletech.info article said 118nm but I have my doubts that I'll be able to get it that tight on an assembled motor and without a proper tool to fit the square recesses.

 

[Mistacat]

These spigots are usually a very tight fit in the head and can take a lot of effort to remove.
I have to remove them to be able to clamp the head down to the bed on the Bridgeport.
Heat in the oven then remove with diy tool as photo.
The tube needs to be a close fit over the spigot a piece of angle and a scrap socket, not pretty but it does the job.
Probably worth spending a few minutes making a tool to be sure they do not come loose again.

[/IMG]

 

[MickDB1]

I can understand not wanting them to move or leak inwards but my logic is ptfe = plastic tape for everything - is as tight undoing as it was to tighten.
My heads ( I have 2 sets ) and dellOrto carb inlet stubs they dont/havent come undone.
JMOOC

 

[Packer]

I have done the heat & cold with red thread lock. Used a length of right angle steel to tighten the spigot.

It's transformed the way the bike runs at lower revs. I couldn't get it to run smoothly below 3,000 rpm previously (although it was great above that) it was lumpy and harsh, now it is smooth from virtually off tickover. Reset, the carbs too as I had adjusted them in pursuit of better running before discovering the air leak on the right pot.

Learning a lot about this old bike.

 

[Packer]

I really need to learn how to weld and get a welder Mistacat.