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Can you slow down recession??.

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DubbyDo Officially Full-On Dubber

276 posts · joined Jan 2012 ·

#1001872
We are nearing the final stretch in our around Oz journey and I have come up against the do we or don't we problem. Driving in to Karratha from Broome 4 ( or 5🤪) weeks ago I found no.4 ex valve was tight, no biggie due for an adjust anyway. Leaving Kalbarri after visiting Monkey Mia and Coral Bay roughly 1500km, I noticed power dropping and missing, checked valves again at Northhampton and found no. 4 ex tightened again. Worried now and checking every 500-750kms, bit tighter every time.
Before we left North Coast NSW I had the heads stripped, cleaned, crack tested and told they were good to use so fitted new ex valves cleaned the inlets and refitted. Also asked them to check the seats which were apparently serviceable. Asked for new guides to be fitted but unsure if this happened (learned a good lesson here Re replacement new head cost to recon cost!)
Checked again this Friday just gone in Denmark, not closed up but tight and running out of room on the adjusting screw. When adjusted correctly it runs like a dream.
So after that long winded story I was reading on the samba causes of valve seat recession and stretching of the valve( don't think this is the case as it runs well when adjusted) shouldn't be running lean, twin 40 IDFs 55idles 120 mains and only sitting on 3200max on the hi way.
However.......
Towing a 6x4 box trailer with shit in it, had it on the weigh bridge when we left combined mass was 2840kg so we dropped 90kg off it and stopped trying to get over hills maintaining speed.
In Darwin I fitted a 009 dizzy as I had one that had a pertronix electronic setup.(max advance 32')
Temperatures climbed after we left Emerald QLD to mid 30s for most of our travels till we got to Jurien Bay( bloody head winds too😠) but any pretence of speed was dropped accordingly.
I am going to fit the original svda dizzy tomorrow and keep our fingers crossed for the Nullarbor.
This wasn't meant to be a novel, the question is can you stop/slow down recession, for a period anyway if you back the CHTs off?

vduboy Insano Dub Head

702 posts · joined Oct 2012 ·

#1001881
Are you running lead replacement stuff in the fuel? Eg flashlube valvemaster or the like? I know dubs should have hardened valve seats already but it can't hurt to give the valve some cushion. P.s in twenty years of working on hi revving bikes I have never seen valves "stretch" It is almost always seat/valve wear that causes recession. Or worst case cracked head and the seat is moving around and getting pounded in to the head.
Good luck though, try and keep revs down as much as possible.
It will all be OK in the end, if it's not OK it's not the end!

modnrod Fahrvergnugen

978 posts · joined Mar 2011 ·

#1001883
DubbyDo wrote:........ the question is can you stop/slow down recession, for a period anyway if you back the CHTs off?
Yes.
I guess if you sit on 90-100 you should be right.
Hopefully.

Just as an aside, I do remember having to run on 3 cylinders (plug out) when the plug thread was stripped once..........from Alice to Darwin on a Squareback in the wet season. Really, really gently.

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 ·

#1001896
far out - that was over 10 years ago

and I remembered it 🤖

geeez - I'm getting old
Futue te ipsum!!!

DubbyDo Officially Full-On Dubber

276 posts · joined Jan 2012 ·

#1001910
Thanks guys, Plonked the original dizzy in and took it for a spin to Albany. Didn't go over 3000 and no trailer behind, ran sweet as. Bizarre, I cracked up reading that post by kombikim, same story as ours nearly word for word. We have gone a lot further but our troubles didn't start till a lot later in the trip too. Am going to risk the crossing, just going to take it real easy, am worried about the climb up the Blue Mountains from Lithgow for the same reasons. Fingers crossed

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 ·

#1001919
Come into Sydney via Goulburn. Much easier
Futue te ipsum!!!

DubbyDo Officially Full-On Dubber

276 posts · joined Jan 2012 ·

#1002020
Our destinationis in the Blue Mountains, Glenbrook. Would be easier climbing from the eastern side wouldn't it?

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 ·

#1002021
certainly would

that climb in to Mt Victoria is fairly short but REAL steep
Futue te ipsum!!!

karmann141 Wolfsburg Wizard

485 posts · joined Aug 2009 ·

#1002035
Hey Dave - love reading about your adventures - certainly have life long memories for your family especially the kids.

Back to your original question: Can you slow down recession??

Yes you can - you can even stop it completely: Fit a Subie engine!! then you can go where you like, when you like and drive on your terms not on the engnes terms.😂

I love aircooled VW's but hate them in a touring camper.

I admire your resolve.
1961 K Ghia - Porsche 5 sp, EJ20T, Brembo's, Dble A arm susp
1974 L Bug - Porsche 944 brakes, Boxster 16's
1974 Bay Camper - EJ20, twin radiators, Boxster 16x7's
Half Beetle trailer with Boxster 16x7's
2011 Tiguan TDI 4Motion
2010 LR Discovery 4 TDV

DubbyDo Officially Full-On Dubber

276 posts · joined Jan 2012 ·

#1002052
Thanks Karmann, the subie alternative has been thought about quite a few times, usually when going back to 2nd when climbing a hill! Don't think I can do it but, love the noise, the adjustments etc etc of being aircooled. After this trip any camping duties will be much closer to home