plug wire

Jim C

Member
Jul 11, 2010
201
5
18
Long Beach Calif
I have been putting together a 29 inch cruiser for a long time. This has been a very frustrating build and I have lost interest several times. I started this build using a 49 cc 4 stroke motor and got it running but decided to go with a 66 cc 2 stroke and that is what I am working with now.
The motor is installed and about ready to go. When I mounted the ignition block the insides of the spark plug cap fell out on the floor. My attempts to reassemble it failed so I bought a new ignition block and installed it today. I put it on the bike and checked it for spark and it did work. When I pulled the spark plug of of the cap the insides fell out and onto the floor. I am willing to buy a new ignition/coil but really want a better quality unit than the ones that seem to fall apart. Who sells a good product or how can I fix the caps I already have?
 

Kioshk

Active Member
Oct 21, 2012
1,152
7
38
Connecticut
The CDI (the black block) should be fine...these are basically indestructible. The rest of the ignition hardware STINKS. Replace the wire and cap with a decent quality automotive assembly. The wire leading into the block is actually screwed in there, and kept from loosening with glue. You can simply unscrew the wire from the block (lefty-loosey) and screw in your new and cut-to-proper-length ignition wire...no glue necessary.
 

2door

Moderator
Staff member
Sep 15, 2008
16,332
137
63
Littleton, Colorado
In addition to the above advice you need to know that where the wire goes into the CDI there is a small threaded protrusion that looks like a sheetmetal screw poking up from the inside. While you're digging the glue out to remove the wire be very careful and do not damage that screw.

As for the wire, I see ne need to replace it. The ignition wire that comes in the kits is a metallic conductor wire that is superior to most of what you'll get from an auto parts store today. They sell resistance wire and the higher the resistance the less current to the plug. If you decide to use resistance wire you should know that there is no metal conductor to thread onto the screw in the CDI. You'll need to find the exact center of the wire as you thread it in.

The spark plug boot that is in most kits is the weakest link. It should be replaced with one made to snap onto the top of a spark plug as opposed to that silly spring thing that is supposed to hold onto the threads on the top of the kit plug. Ask for a spark plug boot at the parts store. They come in straight design, or angled. One with a 90 degree design works well.

Good luck.
 

Cylon

Member
Jun 26, 2015
346
9
18
Maine
BTW it helps to have complete cdis like that which come with the kit on a back up all the time I try to keep a few around as I help others fix there bikes in my area. Some of them work great and some are duds. I doubt they have much QA for the kits.
 

2door

Moderator
Staff member
Sep 15, 2008
16,332
137
63
Littleton, Colorado
In ten years of building and riding I've only had one CDI fail. I maintain that most of the ignition problems seen are the result of that plastic spark plug boot which both of those links show as part of their system.

GET RID OF THEM and use a boot made for automotive use. Those heavy plastic kit supplied boots are JUNK!

Tom
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
16
0
memphis Tn
Never had a CDI box fail yet.
DOZENS of coils, but never a box.
I went to the Screaming Roo CDI/HD coil combo and have not had to touch it in about 2 years
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,549
238
63
living the dream in southern california
I had one cdi fail. After two years it just didn't spark anymore. You old timers know me, so no, it wasn't bad connections, crappy solder, etc. Just quit working.

I always changed the plug wire to a 7mm copper core wire, new boots and terminals. All the bikes I built, the stock wire went straight into the trash.
 

Dead66

Member
May 11, 2016
81
0
6
Pawleys Island
I have a PK 80 from Ozark Cruisers. The wire to the CDI seems to be formed into it as it was built, or at least glued in. Regardless, I am not looking to take it apart if I don't have to. But the boot has nothing more than a spring stuck up in it that is then attached to the wire. It certainly looks like a sorry way to do it to me.

Can I buy just another boot from auto zone and attach it in some way?
 

Dead66

Member
May 11, 2016
81
0
6
Pawleys Island
Also, I am trying to get this bike tuned up. Straight out of the box it runs, but it is not top notch. Up until yesterday it would sputter a good bit as I accelerated, then it would never get to really humming. It seemed to work best when I went to full throttle and then backed off just a hair. At that setting the motor sounded great and really hummed. But when I gave it full throttle it would sound like it sort of bogged down just a hair.

I threw away the chinese plug today and put in a NGK B6hs. I also changed the needle setting. It came stock with the clip on the third rung down. I moved it up to the second rung down from the top. Today it seems to sputter a lot less, but it does not seem to go as fast as it did yesterday.

Thoughts?
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,549
238
63
living the dream in southern california
To answer your first question, yes, you can buy a boot and the crimp from most auto parts stores. If you never made your own plug wire end, google it. There's a youtube video for it.

Second problem may be mixture (too rich, it sounds like.) Changing the needle setting, jet, or fuel to oil ratio might work.

Could be oil clogged pipe, oil soaked filter element, or..?

Or it just might be the break in blues and it'll go away on it's own.
 

Jim C

Member
Jul 11, 2010
201
5
18
Long Beach Calif
I bought a NGK high performance plug wire hang plug cap. I installed it on the bike. I haven't started it yet. I bought some 40:1 True Fuel to start out with. My back is bothering me so I am not going to start it yet. The back should clear by tomorrow.
 

Dead66

Member
May 11, 2016
81
0
6
Pawleys Island
Thanks for the help!

I installed a new boot on my new NGK plug today. But still not getting 100%. But I also managed to mix too much oil so I don't know if that is holding me back.

Meanwhile, while riding today my leg got wet so I looked down. The tube that is attached to the gas supply line had fallen completely out of the side of the Carb. I stuck it back in and got home. Upon inspection there seems to be nothing whatsoever that is to hold it in place. Is this right???

I don't mind continuing to work at it, but maybe I should just buy a nice carb and forget it?
 

Cylon

Member
Jun 26, 2015
346
9
18
Maine
JB weld my friend, its chemical resistant and will be a perm fix. Only use a little so you dont clog it.