jennygirl

Hi yotatechers! It has been a while since I posted here! Hopefully nobody is mad at me for taking some time away

I have a new love in my life, and she is a 2 wheeled vehicle. A brand sparkling new Moto Guzzi v7 in fact! Anyway I wanted to get down to business!

My truck has been doing great. I've put almost 4k on her since posting last, with several majorly successful offroad desert missions to surrounding areas. Unfortunately these expeditions haven't come without consequence, apparently.

Well I dunno if the consequence is directly related to the offroading or not, perhaps this was from on-road use.

Basically what I have is a hunting idle that has grown progressively worse over the past 1k miles. After one particularly rough offroad adventure, I noticed it was really choppy at idle... well, really anything below 1,500rpm. I did a leakdown & compression test and found that it was only getting 90psi on cyl1 with leakage through the intake valve. Popped the valve cover and confirmed it. Somehow intake valve on cyl1 had become WAY too tight (no clearance at all). Readjusted and boom, smooth engine again. Unfortunately, this did not last long. After another couple hundred miles, the SAME thing! Readjusted, okay cool. Then again after even less time just recently. By now, the tappet screw is much farther out than the other threads. Something is not right here.

I have a feeling it is contributing to the idle issue, but not sure. Anyone ever had an issue with valves repeatedly losing their clearance by becoming too tight? Seems weird to me. I feel like the seat must be pressing itself out or something. Or perhaps things are warping? I'm not even sure if that's possible.

Oil and coolant levels are good, I haven't burped it in a while though so maybe some air in a coolant passage causing the idle surge. But that still doesn't explain the valve stuff.

Any and all help/suggestion is appreciated. I am already preparing myself to just tear her down and do a rebuild for the heck of it now that I have another form of motorized transportation

And of course also just looking forward to saying hello to y'all again! It's been too long.

millball

Kinda strange for an intake valve to be loosing clearance like that.

Is it a non-OEM valve or replaced valve seat??

Sometimes mismatched seat and valve materials can cause resession of the valve into the seat. Usually its exhaust valves though.

Gotta love those Guzzi's! I've got an 850 Eldorado Police that I've been riding, probably longer than you've been alive. Hows about a pic or two of your new one??

jennygirl

Hi millball. Thanks for the input!

I honestly don't know, I'm basically positive the previous owner rebuilt at some point (purchased at 490k miles) and no idea what kind of parts they used or how deep their build went. And I haven't ever pulled it apart to that level to be able to check myself. Seems like I'm going to have to pull it apart at this point anyway, though!

Let me get a recent pic of the V7 tomorrow, the latest pic I took was a few weeks ago before I'd done a few of the mods on there now And yeah I love that horizontal V twin. Just too good. Ugh. Only had the bike 3.5 weeks and already 1k miles!

rustypigeon

Sounds like a bad seat. Valves can also stretch over time but I have never heard of one stretching in a couple hundred miles.

jennygirl

Maybe it's worth getting an engine camera to peep it through the spark plug hole.

Or maybe it's more worth it just to rebuild since there's likely nothing I can do to fix it from the outside?

wyoming9

iTrader: (1)

Glad your ok I had thought something might have happened!!

When you never replied back .

Glad your OK!!

With the mileage on that vehicle no telling if those are still the original head and valves.

millball

Pictures of the inside of the combustion chamber not likely to help, but of course you need the camera. Theres no excuse too small to justify new tool aquisition. :-)

If your oil pressure and oil consumption rates are good, head work and possibily timing chain/gear/guides may be all that are required.

jennygirl

Nice to see you again!! Yeah I guess there is only one way to find out what I'm working with. I'm gearing up to overhaul the head.


Exactly my thoughts on the tool acquisition Yes I was thinking I would do the dual row timing chain upgrade and I am also curious what will increase reliability as far as head upgrades?


In other news, I am growing increasingly suspicious that my surging idle is TPS related. It appears to only happen during idle or very very light throttle. I am pretty sure it's to blame. When under normal load, the engine is smooth like butter (except when cyl1 intake valve needs to be backed off again )

I dunno if any of you remember (maybe wyoming does) but I serviced my TPS by opening it up several months ago. Well after my repeated trips to the desert, the silicone sealant I had used to seal the TPS back up has since cracked and I think maybe it's to blame. Time to pop the TB and see what I can find. Perhaps simply reseating & resealing it with some proper gasket maker will fix the idle thing (hopefully). I'd like to get that fixed separately from the valve thing if I can, that way I will have a bit more confidence going into the head work.

Oh and the pic of my new guzzi, as promised

Odin

Welcome back Jgirl.
It does sound like that head is gunna be coming off for a repair or replacement.

Nice bike!
You don't have to explain your disappearance when it comes to feeding the addiction for two wheels!

RJR

I'll echo the welcome back, jennygirl. I was hoping we'd hear from you again. But I understand the need to go off and do other life things.

As far as your valve problem, I think it's just your truck's way of punishing you for transferring your affections to another vehicle. These old Toyotas are sensitive, and if they think they're not your first love they'll turn on you.

jennygirl

You guys make me laugh out loud literally

Thanks for the warm words, and I wouldn't be surprised at all if this is just my 22re pouting a bit because it hasn't been given full attention lately. It knew it would get more attention this way! And it sure is getting more!

Odin- sweet pic! And thanks for the welcome back

rworegon

Welcome back! Mad? Never! Glad to see you 'round here again.

jennygirl

Got a new (used but working) TPS from ebay for $20 shipped. Installed it today and happy to report the lumpy idle has been solved. Still need to go deeper into the head to sort out the mysterious tightening cyl1 intake valve.

At least my truck seems to be happy with me... well, for the time being at least

rworegon

Cool the TPS fixed the idle gremlin.

It will be interesting to see what the valve issue ends up being.

Odin

Watching with interest.

Shady Cadence

I think your seat is migrating into the head. Pull your intake off and look down the runner at the valve/seat. Look for metal peeling back from the seat. If the seat is loose enough in the head to be hammered against it the aluminum will have work-hardened, causing it to become brittle. I would suspect this before a stretching valve stem.

jennygirl

What would cause the seat to migrate like that? 'Cause this is sounding like the best hypothesis in my brain.

I am going to have a look within the week. This problem seems to get worse every time I drive it, so I am trying not to drive on it at all at this point. So I can get a good look at the valve seats by taking the lower intake mani off?

The valve issue appeared after a good offroading trip, including a 32F cold start to go home. I was running 10W40 synthetic, and I remember it barely started up! Definitely not the best choice of oil, I had no idea it would be that cold. I feel like that cold start had the most to do with it because the problem first became noticeable the next day after I got home. Any ideas? Appreciate the help you guys!

wallytoo

iTrader: (1)

probably more coincidence. 10w-40 is fine for that temperature. it was 28* here on june 3, and i'm running 10w-30.

wally

jennygirl

I figured as much. But I am no oil expert.

Still wondering what would cause the seat to migrate.

And if it is, what is the fix? New head?

mwisham

A good machine shop should be able to replace the valve seats and do a valve job on it. That should be less than a new head. I recently had a valve job done on a 20R w/o seats though, for $150. They surfaced the head, installed helicoils in any bolt holes that needed them and did a valve job for that. I thought that was a reasonable price. If you are wanting a little more performance, you might want to look at a different cam since you will have the head off anyway, that would be the perfect time to do it.