Suzuki B120 spark diagnosis

[TehPoopsmith]

Hi all

I just got a Suzuki B120 over the weekend and i am having some difficulty getting it running. It seems to have intermittent spark. eg you kick it over and it will turn over about 6 or 7 times but only spark once or twice.
I think (and I am not sure on this at all) that it means the condenser is stuffed. But I don't want to go pulling it apart unless I have to because the condenser is under the flywheel/magneto cover. So I would have to spend half a day making some kind of flywheel puller.

So is there any er... more senior mechanics who have experience with points based ignition system?

Thanks
Guy

[F5 Dave]

oh dear.

buy a flywheel puller, you can get them on Torpedo7 or any bike shop for std jap bike so they will fit a heap if other stuff. Should cost maybe $20.

Chances are the points are knackered/dirty/closed up. Or condenser is futt. but you'll need to get near them & the puller is simple & easy. Anything jerry rigged will knacker the crank or flywheel.

[imdying]

Yup, the Motion Pro importer has a heap of different ones them, any bike shop can get you one.

[Edbear]

You have got a classic bike that was extremely popular back then and if you google it you should find plenty of info on them. I liked them and would like to see pics.

[TehPoopsmith]

Thanks for the info, I will have to try find a puller. Its a weird one though its got 3 6mm bolt holes in a triangle pattern instead of the usual internal thread. I think if I cant find one I will just have to get a piece of plate steel and drill the holes in it and weld a nut in centre to push it off the crank. I will take some photos later today to clarify, and so you can have a look at the old beast. Its relatively tidy for an old girl and it has only done 9000~kms.
I also have an A100 so I am looking forward to comparing the engine characteristics of rotary valve 2t and piston port 2t back to back.

[F5 Dave]

Really? I was sure a mate had borrowed my puller for his 120. My RM80 ign on my bucket I had to build a plate puller but it was easy as. Try a bit of heat too.

[FJRider]

The points assembly should be adjustable. Usually held in place by two screws (or three). One (or two) of those is the main body holding. One is the adjustable one that sets the gap.

If any of those screws come loose ... :pinch:

The pad on the spring-loaded arm (that contacts with the rotating main center [off-set center] shaft gets worn and the gap does not happen (and no spark)

Both faces of the contact points themselves get dirty/distorted/destroyed and can be cleaned/refaced (if they aren't too buggered already) with a small (nail ??) file.

Points assembly's used to be easily replaceable ... see you local dealer (or wherever) to get a replacement set ... If the fitted one's are stuffed.

Kick it over in (semi) darkness and you should see spark at the points.

Sometimes the points can be replaced without flywheel removal ... but your model I'm not sure of.


But the points on older bikes is always a good (best) place to start looking for issues.

To adjust ... a Phillips screwdriver for the holding screws (don't loosen to much) and a flat (to adjust the arm) is required.

[TehPoopsmith]

http://s1060.beta.photobucket.com/user/Guy_Macarthur/library/Suzuki%20B120

- Theres also an album showing my A100 in there

Theres a couple of pictures there, I have new points on order. No longer available through Suzuki but i found some in the UK on ebay. Paid all of about $12 so fingers crossed they arrive!

Though I will start by trying to work with the ones I have. They are opening and closing, and spring tension is good, But I am unsure of condition of the contacts.

[FJRider]

http://s1060.beta.photobucket.com/user/Guy_Macarthur/library/Suzuki%20B120

- Theres also an album showing my A100 in there

Theres a couple of pictures there, I have new points on order. No longer available through Suzuki but i found some in the UK on ebay. Paid all of about $12 so fingers crossed they arrive!

Though I will start by trying to work with the ones I have. They are opening and closing, and spring tension is good, But I am unsure of condition of the contacts.

Gap width is important. A small piece of folded wet and dry sandpaper swiped between the contact points (with points closed) does a quick clean, a photo with a 6+ pixel camera and zoom in on the resulting photo is easiest way to have a close up look at the points .... and result.

[Grumph]

The last B120 with ignition trouble I looked at was giving an intermittent spark because the timing side main bearing had about 1/8inch of vertical play due to being totally stuffed.....

Best of luck.

[Edbear]

http://s1060.beta.photobucket.com/user/Guy_Macarthur/library/Suzuki%20B120

- Theres also an album showing my A100 in there

Theres a couple of pictures there, I have new points on order. No longer available through Suzuki but i found some in the UK on ebay. Paid all of about $12 so fingers crossed they arrive!

Though I will start by trying to work with the ones I have. They are opening and closing, and spring tension is good, But I am unsure of condition of the contacts.

Nice pics. Not too shabby either, shouldn't take too much to sort out, they are a very basic bike. From memory I think they were a four speed box?

[FJRider]

The last B120 with ignition trouble I looked at was giving an intermittent spark because the timing side main bearing had about 1/8inch of vertical play due to being totally stuffed.....

Best of luck.

After he is sure he has the points working properly ... he can check the timing is looked at.

Who has a timing light anymore .. ???

[TehPoopsmith]

Fixed it a few weeks ago, made a flywheel puller and found that a couple of wires inside the magneto had been rubbed through so replaced them and away it went!. Just bought a new project now though so selling it if anyone is interested? Runs really well and it an awesome little bike. The chrome is relatively good condition.
Needs to be re-vinned but has the cool black plate and original rego papers.

Only problem it currently has is that it is not charging the battery, I will look into this. Probably just a loose wire as it started after I took the magneto cover off to get it sparking.

Check out the new photos on photobucket
http://s1060.photobucket.com/user/Guy_Macarthur/library/Suzuki%20B120?page=1

Wanting $600 ono in Hamilton.

Can post a video if anyone is interested. Going to take it to the vintage bike swap meet next weekend and if it doesn't sell there then it will be going on trademe.