CB100 Project - not starting

[travisvisual]

Working on Tracking a CB100. When i bought it, it wasnt running. needed a whole clutch basket, plates and all and thats all the guy said it needed. The carb was basically dissembled and in pieces so I replaced it with one off a ebay. Installed the clutch and everything else needed, put the carb on, new fuel line, put oil in and tried to start her up.

Got no spark, tracked it down to the rectifier, replaced that and now i have spark. awesome but still not starting for me. I tested the compression cold obviously at 70lbs, from what i read it should be around 115? any advice on where to start?

Thanks!

Travis

 

[hillsy]

That compression is pretty low - but all things being equal it should at least fire.


Start with the valve clearances - if you're lucky one of them might just be too tight and this could explain the low compression. Then check the ignition timing.


BTW - are you checking the compression with the throttle held fully open?


Then if you are sure you are getting fuel to the carb, try some starter fluid and it should fire.

 

[travisvisual]

Yea that was my thought too.

I am going to check the valve clearance and the timing. ive never done it before so I will try and follow my manual to see if i can make sense of it. the points clearance has be a bit confused, they look good but they are touching.

The throttle was fully open, haha i re did the test because i forgot the first time we no changes.

i use starter fluid right where the airbox connects, right?

Thanks for your advice

 

[hillsy]

.....the points clearance has be a bit confused, they look good but they are touching...

They are supposed to be touching at some stage. They need to change from touching to open though.

i use starter fluid right where the airbox connects, right?

Yes - it's probably a 2 person job on a bike without an electric starter - you need to spray the starter fluid in as the engine is turning over so it draws it into the cylinder. Go easy on it though - that stuff is strong and can damage your engine if you use too much.

 

[surffly]

These motors are very easily upset by intake and exhaust issues.
If you are trying to run without a proper air box or a good exhaust then you will have issues.

Have you looked at the factory manual?
Walks you through step by step of things to look at and all in the proper order.

read through it and follow the steps to set everything to factory specs