Recommended Spark Plugs

[gearhead222]

Dear Fellow Members-I have a Grubbee 2 stroke 48cc engine and am wondering what brand and type of spark plug you members recommend. I have a spare Chinese 4 x1.25 metric plug, but understand that there are better ones out there. Also, what is the recommended gap? BTW, GREAT forum! Thanx for any info-Gearhead

 

[CaptJ]

Welcome gearhead222, I have a Grubbee 2 stroke 48cc from bicycle-engines. I live in CA and wanted to keep it legal (Slant 48cc). I just orderd 2 spark plug from Sick Bike Parts dot com
#1 was NGK B5HS for cold weather #2 NGK B6HS for CA. The new plugs didn't fit. I had to remove the head and rind down the three center fins to clear the plug. Good luck and have fun.

 

[gearhead222]

Thanx Capt. J! Do you mean that both plugs you ordered from Sick Bike parts would not fit without modification to the head? Did you have to grind the cooling fins to use your spark plug socket? Do you or any of you members know if the NGK BPM7A or BPM6A they sell would work better without any head modification? Thanx for any specific details from anyone-Gearhead

 

[Pablo]

I never heard of any head needing grinding on the fins to accept an NGK plug. Interesting to know. I'm assuming the wrench hits or something?

 

[CaptJ]

Yep! My regular long spark plug socket 13/16 hit the three center fins on rear of the motor carb side. Very easy to do just remove top nuts (notice how tight the nuts are then put them back same way) I don't have torque wench I think it's 12 lbs. I used a rotary tool with a stone. I cleaned the head with carb cleaner total clean. I oiled the spark hole with 3 in oil. After assembly I had a 20 minute ride, up to 25 mph for 2 minutes.
I'm on my first tank of gas.

Have Fun Yall

 

[cabinfever1977]

our kits come with a sparkplug remover and fits just fine with the plugs.

 

[CaptJ]

I never heard of any head needing grinding on the fins to accept an NGK plug. Interesting to know. I'm assuming the wrench hits or something?

Pablo, the thin wrench that came with kit will work but it's hard to fit around the plug. On my engine I had to tap down the (kit) wrench with a hammer. After the (kit) wrench is barely on, it's hard to remove. For me using my USA long spark plug socket after the grinding makes life easier.

 

[AussieSteve]

Most kits come with a plug socket, but they're absolute c r a p.
A B5HS or B6HS are still the best plug choice for these engines.
If you have to grind the fins a bit to use a decent plug socket, so be it, I reckon.
Throw away those (rubbish) stock plugs.

Pablo, thanks for your help with my studs. Also, love the slimline air filters. They make the stock ones look like rubbish.
Used one of your metal exhaust gaskets, too.
First test ride with billet head, 3L tank, Sick Bike Parts air filter, 'O' ringed alloy inlet, Mountain Mirrycle mirror and VELO recreational seat tomorrow. (Done 370km, so I'll go from 16:1 to 20:1 oil, too, with 8ml/litre octane booster as before to suit the hi-comp head.)
Should be fun.
... Steve

 

[AussieSteve]

I was gonna PM, Paul, (Pablo), but couldn't attach pics. (Plus I wanted others to see how decent vendors conduct themselves.) You guys have won me.
The thread on the studs was beautiful. I fitted both flat and spring washers with a couple of mm to spare, just as it should be. Previously, even with just a flat washer, the nut wouldn't fully tighten down on the stud.
Once again, thanks for the help.
For anyone reading this, Sick Bike Parts are #1 for parts and service.

... Steve

I posted this in another thread yesterday:-
(I didn't screw the studs in too hard. They started to bind a bit before bottoming. Nothing wrong with the studs, I think there was a bit of loose metal in the bottom of the holes. Didn't want to strip anything. The nearest one protrudes the furthest, the others are about 1mm closer.)

 

[Pablo]

When I get some free wrench time, I'm ordering that head.

NICE engine set-up.