Has anyone run a series of dyno test on the effect of spark plug indexing on multi port 2C engines ? I have some thoughts pro and con.
I run a plug with cut back ground electrode to lessen the effect of flame kernel shrouding and am guessing that helps reduce dependence on indexing in these motors. In 4 & 5 valve 4C motors it made a difference when the plugs were installed w/o indexing as during a pit stop so I am guessing that it would be a similar situation on multiport 2C engines. I don't have a dyno available small enough for these motors and I'm RETIRED I'll let somebody else do the work.
BTW I have NGK CMR 7H plugs for sale 3 plugs SHIPPED cont USA $ 13
Ed

Gone back and forth threw the years indexing and then not .... Don't any more and have found the effort not worth the perspective power increase ???

I do however grind back the ground electrode to be at @ mid center electrode.

Scott That is what I had pretty much decided for these engines but needed confirmation . There are a few tricks on shaping ground electrode which makes it fire at a lower voltage/higher pressure but not really worth the trouble if every thing else is OK. TNX Ed

Ed,
I have spent quite a bit of time playing with spark plugs. I have shortened the strap so that it looks just like the plugs we use in our race car, I have made the end of the strap into a point and even started shortening the plug wire in the quest to find some more power. After all was said and done I am back to just screwing the NGK plug into the cylinder and forgetting about it. I think with the limited amount of power from our ignition system it is hard to gain power from what we have available.

Carlo
CC Racing Engines

what is the best gap for the new ngk ird.plug cr8hix and can u tell me whats the diff between the walb. 257 vs the walb.833 big bore carb ty ron ???

As they come from NGK has been just fine, : think thats @ .022" - .025"

Zenoah specs state 0.6-0.7 mm for plug gap. (0.23-0.27) So like Scott said, pretty close right out of the box.

As for the carburetor...are you certain about the 833 number? I know there is a WT-813 that's been out for some time now. It's sold in a high performance kit from Zenoah and comes with the Irridium spark plug you mentioned. This carburetor is the same bore as the WT-257, with the addition of the primer bulb and most importantly it features an internal accelerator pump. The reason is to help reduce low en lag in systems tuned for maximum top end performance.

Marc I got Scotts specs this morn but didnt say anything about the carb tho an yes my numbers where wrong it is the wl 813 i order the kit u mem. the say it gives better preform. but ill try an find out. Plan on doing the motor when i get back to the states is to hard to get shipped to up here in the great white north of canada. do 6mths here 6mths in FLA.This site is unreal am learning alot just from reading all the articles thats diff usually just look at the pics u no haha Ron

Ron,

Where in Northern Canada are you exactly?

Marc, In a lil town called Honey Harbor.Ontario about 250 miles north of toronto up on georgian bay thebay of 10,000 lakes we are right on the water on a inland bay got lots of nice places here to run. i have to go about 50 miles to go to the local hobby shop so i have alot of my parts 2nd day aired here its alot faster across the border.when i get back to the states in late oct. gonna pull motor out an have it built dont no who yet ever heard of bozi sports in indiana he has a 84 inch fountain with 4 bz4 mod 26 z motors with them 2 in line looks rad but dont no how it runs Ron