Bonneville America Forums Forums Technical Forums General Tech Plug reading

How do these plugs look?
This was right after a 30 min, 70mph,4000rpm run.
http://www.bonnevilleamerica.com/photopost/showphoto.php?photo=2487

Not bad. They look normal to me, but I'm a newbie at this yet. I asked my dealer's service guy yesterday how to do a check. He told me the best way to read 'em is to run the bike right up to the red line in 2nd or 3rd gear, then grab the clutch, dump the throttle and hit the kill switch at the same time (well maybe the clutch a split second sooner). BTW red line in 3rd gear is over 70mph for my 05 Speedy. Then pull off the road grab your trusty socket wrench, pull 'em and have a look. Mine looked good, maybe just a little lean.

Here's a good link:
http://www.spark-plugs.co.uk/pages/technical/diagnosis.htm

Regards,
Rich

Thanks for replying.
Try pulling out the snorkle in your airbox.
You might be suprised at performance increase.

They look a bit lean. They should be a tan color.

I just rejetted today.
The stock jets were 120 mains.
I replaced them with 125 mains.
I got the jets & allen screws from Brent.
I am running TB Pipes.
AI removed.
Snorkle removed.
Mix screws 4 turns out.
I will put some miles on the bike soon,& then check the plugs again.
Thanks for replying.

How'd the 125's do as far as performance? Any gains? I'm going to 130's as soon as they arrive which may be today. I'm hoping i'll gain some since i know the top end is too lean right now.

I had my setup with the 120 mains on the dyno.
It came out to be 64.1 hp.
Did not dyno with the larger mains.
It does seem a little stronger from 5000rpm to redline.
Nothing really dramatic though.

i wonder if you might have been better off going to 130's. I was going to go to 125 mains but was told by a few people here to go with at least 130's. I'm pretty sure my bike which as you know has the same pipes and snorkel gone as your's was on the verge of being too lean. you probably already read what i've posted about this, but i removed the snorkel plate for a round the block test run to see if enlarging the hole to the same diameter as the filter would give me more power. That bit of extra air cause the bike to run horribly which tells me i was alreaady on the verge of having too little fuel. So to get it past the lean state to "just right" i think the 130's will be more correct than 125's would have been. I'll find out s soon as they arrive and let you know. Plus i wanted to make sure it's rich enough so i have room to create better airflow w/o the described results when i removed the plate because i hope to cut the plate for more flow and get a K&N. Then the 130's may even be too lean, but i shall see soon enough and i'll post when i figure it all out.

I think the stock mains are 120 with 42 pilots. The SS long slash cuts I put on my 05 BA came with a re-jet kit which my dealer installed. The mains were changed to 128, the AI removed, but they did not remove the snorkle. The bike performed (and sounded) MUCH better but had excessive backfiring (popping) on deceleration. I took it back to the dealer who readjusted the carbs and changed the stock pilots to 45 which eliminated the problem. When I asked, they didn't recommend removing the snorkle - not sure why. I'm still using the stock sprockets (17/42) and the bike runs great but I lost about 5+ mpg after all the mods. Is this normal? My riding is about 70% around town and 30% hwy and I'm averaging about 38 mpg. Many posts on this forum claim way better. I may change the front sprocket to a 18T which might improve the milage, but I'm waiting awhile. I now have a little over a 1000 miles on the bike (2 months).

One correction - It's probably more like 60/40 city/hwy.