V7 plug cap swap, revisited.

[Toecutter]

So, swapped the wife's caps this evening, haven't fired it up yet.

Noticed however that there is NO way the "cap to plug" rubber boot is gonna fit in the plug well... So I left them off. Now, without that boot, the caps tend to "wiggle"... Anyone foresee any issues?

[stevet]

Just swapped mine a few days ago with the units suggested by MI from that recent thread.  2016 V7II.

The new cap-to-plug rubber fits down in the plug well with pretty much a perfect slip fit.  But I wondered the same thing as I was putting it all together.  I had to give the caps a good push to get them seated on the plug.

I'd think those boots help support the cap from wiggling around from vibrations.  Are your rubbers just too tight, oversized for the plug wells?

Steve.

[Toecutter]

Even off the plug, they have a larger diameter than the plug well... Cap is the NGK XB05F.

[Toecutter]

Yup. Just went out and retried. Those boots are NOT fitting in the wells. Hell, if I turn 'em upside down, the work really well as corks for the plug wells. 

[stevet]

Strange.  These were the ones I bought from my local shop, the same ones mentioned at the MI link-
http://www.motointernational.com/service/tech-update-all-single-throttle-body-moto-guzzi-v7-models

Went to the garage just now and verified it off the boxes, they are the same ones-
NGK plugs- CPR8EA-9  Left the gap as they came, just snug on a .88mm feeler gauge.
NGK spark plug covers- XB05F

It's one of two things, I guess.  Guzzi didn't cast/drill/grind the hole big enough, or NGK put a bit too much rubber on that particular run of boots.  I'd blame Guzzi before blaming NGK.  If there was just a safe way to grind or hone those spark plug wells without getting grindings in through the spark plug hole...

If you bought the boots locally, could you go back and try another boot?

Off topic a bit, but for my factory wire boots, I found when I unscrewed the boot from the wire, a crimped fitting stayed on the wire and it unscrewed from the boot.  I had to snip off that crimped fitting from the spark plug wire to install the screw-on NGK boot.  That crimped fitting was not unscrewing from the end of the wire at all.  And as far as arcing of the boot to the spark plug, fortunately I viewed none on the factory plugs.  That said, the factory plugs and boots are in the bottom of the workshop trash can.  Anyway, that's the first time I've ever installed a plug boot.  Strange how that new boot thread managed to insert/twist itself into the right spot up the core of the wire.  Working just fine.

Steve.

[SmithSwede]

Warning.  If those rubber boots are a snug fit in the well, they can easily get stuck in the well when you later try to remove the cap, and they decide they would rather be stuck in a well than stuck on the cap where they belong.

Then you have a tight rubber circle deep down a well.  Which blocks your attempt to push a spark plug wrench down said well to remove spark plug.  Which leads to 45 minutes of prying and cursing.

Don't ask me how I know this. 

I'd leave them off, or glue them to the cap.

[rodekyll]

Can you use the old ones?

[Toecutter]

There are no old ones... just those expensive and shitty NGK rubber caps (cap and boots all in one). All four plugs, from both my and my wife's bikes show signs of arcing with those things.

Right now, I'm riding without the bottom boots. Tried all four plug wells, and all four plug boots in each... right across the board, consistently "no". 

[tonUPRacer]

I left my rubbers off. What is the recommended gap for these plugs? I set mine to the what the manual recommended.

[Toecutter]

I second this.

The plugs were all gapped between .86 and .89 right out of the box. I left them as is, and they run great.

[sib]

The NGK product sheet for spark plug caps is very informative.  It can be found at

http://www.ngkpartfinder.co.uk/files/NGK_Spark_Plug_Covers.pdf

In addition to the XB05F cap, NGK also makes an XD05F cap.  The only difference is the plug thread diameter dimension:  the XB05F is intended for 14 mm thread plugs and the XD05F for 10-12 mm thread plugs.  The CPR8EA-9 plug has 10 mm threads, which suggests that XD05F is the proper cap.  Perhaps somewhere along the line in this forum, a typo was introduced and the recommended replacement cap is supposed to be the XD05F, which might have a smaller overall diameter and would fit better in the plug well.  It would be nice if someone here would try an XD05F cap and report back whether it's a better fit than the XB05F.

Also, in addition to XB05F and XD05F caps, NGK also makes XB05FP and XD05FP caps.  The P suffix indicates that the cap is waterproof.  Perhaps these are what we're looking for.

Regarding the plug gap, the suffix "-9" on the CPR8EA-9 plug indicates that it comes from the factory with an 0.9-mm gap.  Although the MG manuals indicate that the gap should be set to 0.6-0.7 mm, I have found that the 1TB V7 and V7II engines run better with 0.9-mm gaps, so, when I replace the plugs, I leave the gaps as they come from the factory.  This wouldn't be the first time that the MG manuals contain incorrect information.

[Toecutter]

It was this http://www.motointernational.com/service/tech-update-all-single-throttle-body-moto-guzzi-v7-models that prompted the purchase of the XB05F caps.

Your link has got me wondering now. I have sent an email to NGK Canada to clarify, but my question of "what cap do I use for plug CPR8EA-9, XB05F or XD05F?" Has been met with a plethora of questions regarding the vehicle specs, as opposed to a simple "this size, this cap" answer.

I'll post any results I find.

(edit: found a supplier with 4 of the XD05FP (p for waterproof housing), so will pick them up today)

[Toecutter]

Ok.

I have swapped and confirmed, I have not heard from NGK yet, however, I have made the switch.

The proper cap is XD05F, or XD05FP. The boot fits the plug well perfectly, the cap engages with the plug more solidly. It is absolutely the correct plug cap.

[sib]

Ok.

I have swapped and confirmed, I have not heard from NGK yet, however, I have made the switch.

The proper cap is XD05F, or XD05FP. The boot fits the plug well perfectly, the cap engages with the plug more solidly. It is absolutely the correct plug cap.

Confirms my speculation.  Thanks for posting.  I wish you many trouble-free miles with your new, proper, NGK caps.

[rodekyll]

There are no old ones... just those expensive and shitty NGK rubber caps (cap and boots all in one). All four plugs, from both my and my wife's bikes show signs of arcing with those things.

Right now, I'm riding without the bottom boots. Tried all four plug wells, and all four plug boots in each... right across the board, consistently "no". 

Got it.  No removable boot.  That sux.

An interesting aside -- you mention the factory gap was .034 and .035 (.88 and .89mm).  This is roughly what I measured on the BP6ES plugs I just installed in the hydro engine.  So that could be the standard 'factory pre-gap' for the current generation of NGK products.  I measured about the same (.036 and .040) on BP6ES in an '04 Stone the other day.  The owner assured me that they were "factory gapped and therefore didn't need checking." The problem is that while the factory pre-gap is close to correct for the current model year, it's WAY WRONG for the older lumps, which want to see .024 - .028.  So please don't make assumptions about the factory gap.  Check it.  A $2 circular gapper is next to the cash register at every parts counter ever installed in every auto parts store everywhere, so there's no excuse to not have and use one at every opportunity.

Thank you very much!

[slowmover]

So the tech update is incorrect?

[anthracer12]

FWIW I also emailed NGK about the same issue a little while back and the response was this:


Thank you for contacting us! You will need plug cap XD05F for the NGK CPR8EA-9.

Best Regards,
Murphy

So I went with the XD05F. I haven't tried them yet but I will soon.

[stevet]

Okay... so I've managed to install, presumably, the wrong cap?  Which was the suggested cap.  My XB rather than the XD?

I guess tomorrow I'll try to pull the cap off the plug and see what happens.

Any reason to believe the physical connection between my XB cap and my CPR8EA-9 plug is incorrect?  Before installing either onto the bike, I snapped a cap onto a plug to see how well it grabbed the plug, and the fit seemed secure.

Steve.

[Dofin]

I don't understand, the problems?  I have recently replaced the oem boots on my 2015 V7 Stone.  the spark plug contacts showed evidence of arcing and I now use denso iridium (threaded tips) with the recommended XB05F boots that I purchased off of Ebay, info below.  I had not a seconds issue during installation and I feel the plug and boot combo has improved the engine start, cold running and the 3.5-4K stumble some what.

Ebay address.  for Boot  XB05F    I guess the XD05F is the one to use?  Oh well.  Still using the XB

http://www.ebay.com/itm/400928270601?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[slowmover]

Could the sparkplugs wells be differenent depending on the year? Mine is a 2013.

[Andy1]

The problem seems to be whether or not the caps fit in the 'spark plug wells', not the fit of the caps on the plugs.
Do the B sized caps have a larger OD than the D sized ones?
AndyB

[Dofin]

The XBo5F fits easily in the plug wells, 2015 V7 Stone?  I can pull them on and off the plugs easily,  waiting with interest if any one gets the info on diameter of the rubber seals on the XB as compared to the XD or if the Plug Wells are different sizes in the older V7s?  Just curious?

[stevet]

I pulled a cap off a plug this morning.  No problems.  A nice snug fit of the cap connection to the plug terminal.  I popped the cap off the plug, and with the cap just above the plug connection, I could move the cap around inside the plug well freely, maybe a millimeter or so of free space between the cap and the plug.  Seems I'm fine.

NGK, CPR8EA-9 plug, XB05F cap.  2016 V7II Stone.  I'm done worrying.  Time to ride.

Steve.

[DanteAl]

Hey - first post :-)

I'm planning on making this fix tonight in the hopes it fixes the power stutter I am experiencing on my 2016 V7 II roughly between 3-4K RPM.

I have the XB05F caps though - everyone still feel it's not a big deal to not use XD05F? Also, I really just cut the cable next to the old caps and screw on the new ones? That easy?

Thanks!

[Dofin]

No No No, don't cut the wires!  the caps UNSCREW and screw back on.  Be sure to get the cap seals properly installed on the wire and plug side so moisture stays out. 

[DanteAl]

Well - I'm glad it was too damn cold and windy to do this tonight - I put it off until tomorrow. The idea of cutting the old caps off came from this post, but I guess for my bike that's not the way to go:

https://www.motointernational.com/blog/news-and-events/post/spark-plug-cap-update-for-guzzi-8v-models

Many thanks for applying the brakes.

Dante

[Dofin]

If you want to snip a bit off to get a better bite when you screw the new caps you I guess when you remove the old caps check to see if there will be enough cable and then you can decide how much you want to trim?  But just cutting after the cap will use a lot of cable.

[stevet]

Hey - first post :-)

I'm planning on making this fix tonight in the hopes it fixes the power stutter I am experiencing on my 2016 V7 II roughly between 3-4K RPM.

I have the XB05F caps though - everyone still feel it's not a big deal to not use XD05F? Also, I really just cut the cable next to the old caps and screw on the new ones? That easy?

Thanks!

Welcome aboard!

See my message above from July 26.  I had to cut the ends of my wires, no choice in the matter.  Working fine from the day I installed the new plugs an caps.  2016 V7II Stone.

Steve.

[MorenoB]

Here we are! After 22.000 Km on my V7 (model year 2014) I've started experiencing some misfires, and I'll chamge my spark plug caps.
I' have XD05F, they should be ok, isn' it?

[sib]

Here we are! After 22.000 Km on my V7 (model year 2014) I've started experiencing some misfires, and I'll chamge my spark plug caps.
I' have XD05F, they should be ok, isn' it?

Yep, and you'll have to also change the plugs from CPR8EB-9 to CPR8EA-9.

Another thing to consider is that for both plugs, the "-9" indicates that they come pre-gapped at 0.9 mm.  Although the Moto Guzzi owner's and service manuals state that the spark gaps should be 0.6-0.7 mm, I have found that 0.9 mm works better, on both my previous '13 V7 Stone and my current '16 V7II Stone.