How lean is too lean?

[TheGingerBeardMan]

LLoydie is the "plug specialist" - Butt plug

Oh Christ - the visions. Someone poke me eyes out.

I imagine now, someone going hard at it with a butt plug, and building up a bit of a sweat with approx. 50 RPM (rams per minute). Then, stopping mid thrust, holding their breath and doing a "plug chop" to see what colour it is. Oh fer gawds sake. VISIONS......bad visions.....

[Stephan]

NZSpokes: i think champion makes some copper plugs

[NZSpokes]

NZSpokes: i think champion makes some copper plugs

Presume it will be a DPR9ea-9?

[Stephan]

NZSpokes: i think champion makes some copper plugs

Presume it will be a DPR9ea-9?

could be champion RAX92YC. But I did quick overview, and it seems that all plugs are copper, only the tip is platinum or iridium. See the link. Personally I use Denso IX27B for years without any problem and believe they are the best option to get the most power.

http://densoiridium.com/spconstruction.php

[Varastorm]

That would worry me. A lot. Whats it like at part throttle at high rpm? If it goes flat then you are close to losing a valve.

look at them with a magnifying glass. See if there are any little silver spots. If so your pistons are melting.

This is the thing Spokes, it runs really well. I know its lean "PoP'n BanG", but no throttle issues at all & I've experienced my fair share of those. I don't have any ali bits on the plugs it's a kind of ash build up. I also had a good look into the bores with the pistons at tdc & all looks black, flat & normal.

GBM makes some good points also, apart from the butt plug gaff

You too are right Kenmoore

Those plugs look lean to me, however if you like the way your bike is going what is the worse that can happen?

I might purchase a set of high comp pistons just in case. Instead of saving up for a slipper clutch

I popped to see the Paul the dyno man yesterday & asked him his thoughts on the matter. Looks as if it's going in in a week or two......

[fabiostar]

it will be good to see what a dyno makes of it as the bike feels good..

[sirch345]

I have read loads about reading plug colours, but more & more I hear about the combination of iridium plugs & newer fuels making reading plugs harder & harder.

.
I wonder about the new iridium and split-fire plugs - with new advanced ceramics. It does raise the question: Do the new advanced tech plugs remain a paler/white colour, due to the ceramics ability to withstand higher "racing" temperatures? Or, does it not make any difference?

Those plugs look lean to me, however if you like the way your bike is going what is the worse that can happen?

From my experience there is no better diagnosis tool than the old butt dyno.

After all you know your bike better than anyone else!

Ride on and enjoy, I found the comment about reading plugs with the latest crop of fuels interesting.

Here are my plugs and they are a stark contrast to yours as you can see.



The one on the left is the front cylinder and the one on the right is the rear cylinder.

The plugs were removed after a rather vigorous ride.

Phil this might interest you
I was looking at the colour of your plugs in your photo's and thinking (as one member says in an old school way probably), your plugs look very lean to me, with the colour of the centre ceramic insulator being so white.

Then yesterday I decided to take a look at my new iridium plugs in the Storm seeing as they have been in there for a few hundred miles now. To my astonishment they are really white both front and rear, perhaps not quite as white as yours Phil, but a lot whiter than I would like. I would prefer they looked more like Kenmoore's shown above.

My bike is running very well IMO, if anything I was expecting it to be running on the rich side going by the outlet spouts on the end can's. So I'm also wondering as some of you have already mentioned (as above) is this something to do with iridium spark plugs giving us a different reading than we used to get from our spark plugs before iridium plugs were available

Here's what mine look like:_

Rear



Front

[Pete.L]

They are spot on Chris.
See the nice bit of tan on the upper arm (earth electrode). This is the best area to check modern plugs in my opinion
The ceramic will darken over time to look like Kenmores and soot will build up on the thread area as it's not as hot.

Problem is, your plug goes through all sorts of temperature ranges and fuel mixtures as you are warming up the bike, opening or closing the throttleor changing the load. They will slowly get darker and darker over time. Your plugs will show you an average of all those kinds of riding. Long rides and plug chops can get you pretty close and burn off a lot of the sooty deposits but normally its better at higher speeds . I'd rather a colortune kit (old school, mines doesn't fit anything modern any more ) but you won't be able to beat a gas analyser.

Watty wrote:
LLoydie is the "plug specialist" - Butt plug

Oh Christ - the visions. Someone poke me eyes out.

Just for GBM

[darkember]

This what you need to check the bores and crowns out.

http://www.ebay.co.uk/itm/like/18169153 ... ue&ff13=80

[kenmoore]

My plugs are iridium and have been in the bike for approx 5,000 miles!

I am still mucking around with the mixtures after fitting some stacks and am wondering how they look now.

I think my bike is a bit rich now.

Soon I will pull the plugs and have a look at them.

Will post pics when I do.

[sirch345]

They are spot on Chris.
See the nice bit of tan on the upper arm (earth electrode). This is the best area to check modern plugs in my opinion
The ceramic will darken over time to look like Kenmores and soot will build up on the thread area as it's not as hot.

Problem is, your plug goes through all sorts of temperature ranges and fuel mixtures as you are warming up the bike, opening or closing the throttleor changing the load. They will slowly get darker and darker over time. Your plugs will show you an average of all those kinds of riding. Long rides and plug chops can get you pretty close and burn off a lot of the sooty deposits but normally its better at higher speeds . I'd rather a colortune kit (old school, mines doesn't fit anything modern any more ) but you won't be able to beat a gas analyser.

Thanks Pete for the vote of confidence, I can see what you mean about the colour of the earth electrode. I'll keep my eye on them. As I previously said, the bike runs very well IMO. The blip test shows up no problems, and there are no flat spots.

This what you need to check the bores and crowns out.

http://www.ebay.co.uk/itm/like/18169153 ... ue&ff13=80

I like that D/M, not expensive either, all I need is a laptop. Thanks for the link

My plugs are iridium and have been in the bike for approx 5,000 miles!

I am still mucking around with the mixtures after fitting some stacks and am wondering how they look now.

I think my bike is a bit rich now.

Soon I will pull the plugs and have a look at them.

Will post pics when I do.

Ken,
Please do post up some pic's when you next have your plugs out.

What are your exhaust can spouts like my Scorpions are sooty,


Chris.

[Varastorm]

Thanks for all the input guys, appreciate it

The problem is that I'm torn between the amazing fuel economy (45ish to the gallon) & top end performance (108ish BHP) tbh.

After the chat with Paul the dyno man & coming to a joint decision of "yep, maybe a little too lean!" I came home & had a good hunt for info on the web.

The decision I've made is to up the main jets . This was not part of the original plan, as I was quite happy with the dyno graph reading of 108ish bhp.

My theory behind this came after looking at reading lot's of "V" twin dyno graphs. The best power for a "V" is achieved @ 12.5/1 AFR.

So with that in mind & with the top end currently running at 12.9/1 afr with Keihin 175F & Keihin 178R. I decided to increase the mains to Keihin 178F & Keihin 180R. Hopefully this will get the top end closer to 12.5/1 & have a knock on effect of slightly richening the midrange also.

Two birds with one stone. The only problem with this is that I don't have a 180 Keihin Main for the rear carb

With the carbs in bits, I had no option but to fall back on the Dyno jet mains, but there is no hard evidence out there to be able to compare like for like, very poor really.

But I trawled through the posts on this forum to see what other people were using & decided to take a stab on using a DJ185 front & DJ190 rear.

The result is bonkers, the pull to the redline has increased again & the PoP'n & Banging has also decreased.

I have not pulled the plugs again to see if there is any signs of a richer afr, but at the moment I am going to let it be.

Since the fitting of the DJ mains I have just ridden it & it feels really good now. Time is coming for another Dyno run.

I have just finished another mod I have been playing with, the fitting a Fork brace. Link if anyone is interested

http://www.xrv.org.uk/forums/varadero/1 ... brace.html

Next up is fitting VTR pegs & maybe a VTR swing arm....

[sirch345]

Interesting to hear what you've been up to again Phil I see you came up with the same thoughts on the main jets as popkat.

I like your fork brace mod

Chris.

[fabiostar]

class act i have to say...