1980 CB100n

[GT Graham]

Hi I’m Graham

New here!
I have acquired a CB100n which I was told on purchase that it was running last year🤥.. after changing coil, rectify, points and plug, along with a new 6v battery I now have a spark, I have by past the fuel tank and have the carb set up on a separate fuel bottle.
It’s reluctant to start.
So am I thinking of checking the compression after checking the valve timing and all good it should start!..
is there anything I should be looking at before I go ahead?

This is new territory for me as I’ve always had 2 strokes
Cheers
Graham

[Bryanj]

Blocked jets and passages in the carb

[SteveD CB500K0]

“Last year” is a minimum of 12 months sat with fuel in the carb. It will probably be sludge.


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[GT Graham]

Thank you both..

I’ll get the carb off  tomorrow and check it out… 👍

[SteveD CB500K0]

I learned to ride on a CB100 on the car park of Bedford County Council offices in 1974.
It was an RAC/ACU scheme, off road for 16 year olds. I had a Raleigh Runabout at the time.

At 17, I went for a “much more powerful” CB125S


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[GT Graham]

 

It’s the smallest bike I’ve owned apart from my mobylettes that I’ve have had  over the years! I still have my first Moby an AV76, which I built years ago..
The little Cb100 takes me back tho..

You maybe be able to answer this, were these little cb100cc any good? 😁

[SteveD CB500K0]

From what I recall, they were identical to the 125, but with 25cc less.


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[GT Graham]

Had a play in the shed and have had the little cb100 running, so I know now that compression is ok, even tho I have had the carb off and cleaned it it still only runs for a minute or so, so for £31.00 and postage I can get a replacement.

I recently bought some tank cleaner off Mad for bikes, has anyone used it, it says leave in the tank for several hours and shake every 30 minutes at room temperature.

Has anyone used this product? Or should I be looking at something different?

[Laverda Dave]

Never tried that product and have always used DEOX-C from Bilt Hamber, excellent product and does what it says on the tin.

[GT Graham]

Thanks for that Dave

just looked it up, I will order some, plus it’s cheaper!

Thanks
Graham

[Sesman]

Plus 1 on the Deox-C.

[Athame57]

Hello Graham
Welcome here, there's a goldmine of knowledge here to draw on too! 

[GT Graham]

Thanks for the welcome.. I’m sure there is a lot of knowledge here!

[McCabe-Thiele (Ted)]

Welcome Graham, good to read you've had it running albeit briefly.

[GT Graham]

Thanks Ted.. a little way to go but it’s getting there

Graham