That was weird.

"What was?" I hear you ask. Adjusting valve clearances on a cage, that's what. Especially as they're ye olde screw & locknut types (which I'm very happy about).

Question though - the manual says 0.2mm inlet & 0.3mm exhaust, measured hot.. Why so loose, bearing in mind they're fairly typical cold clearances on bikes?

And why would all the inlets be tight, & all the exhausts loose? My money'son whoever did them last time getting it wrong, but I was wondering if running on LPG could make the inlets close up but not the exhausts. Seems unlikely though as they were all out the same amount.

 

What did he say?

 

In communiqué

I run .5 cold on the Morini (a pushrod albeit very short ones motor)
because of the L5 cam (standard is .4), and I tend to err on the side of
extra looseness on the exhausts as I think they may run hotter and are
more inclined to burn. Perhaps the previous fiddler thought the same. I
found one on my inlets a tad tight when I checked them. Not LPG, but the
Morini was designed before leaded fuel as we discussed before.

So, summing up, I dunno,

--
+-------------------------------------------------------------------+
| Pete Fisher at Home: |
| Aprilia Shiver Yamaha WR250Z/Supermoto "Old Gimmer's Hillclimber" |
| Gilera GFR * 2 Moto Morini 2C/375 |
+-------------------------------------------------------------------+

 

Pressing 'O' in Agent rendered his, presumablt google-posted, text at
least legible. The technical question is way above me, though.

 

<looks>

oh, yes. Xnews has an icon to clock in the preview pane to word wrap posts
from shitty web interfaces. In about 10 years of using Xnews I've never
needed to look for it before.

Anyway, just as the door was hitting your arse as you left for the piste I
sent you an email...

 

To the ifrance.com address? That's long borked, so osend again to my
work one.

 

Ah, you prolly didn't get mine either... I wonder if I have the work one
somewhere

 

Hmm. Looks fine in XanaNews. Can you let me know what's wrong with it
in Agent & Xnews so I can raise a bug?

 

About the same as my car, give or take .05mm (I can't recall the exact
figures), also measued hot. Mine's a TDi, though.

If it's an OHV motor then the valve train is longer than a bike's
pretty direct OHC arrangement - more room for expansion and more
places for tolerances to play (hah!) their part.

Also, and this is a really wild guess, if it's got an iron block and
head then they're not going to expand as much in relation to the valve
train itself as would an alloy engine, so the cold clearances might
end up tighter.

Might be different valve/seat materials. For example, FZR600s were
notorious for closing up the inlet valves more than the exhausts,
which was certainly my experience of them.

 

It's a modern (designed in 2000) alloy OHC.

Tis possible I guess.

 

Because the exhaust valve get hotter and expands more

 

Which is why the exhausts are meant have a 0.1 bigger gap than the
inlets, but is irrelevant to my question.

 

the OP did not word wrap in both clients