T3 VHB30 carbs. Worn out? |
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Jimble
Falcone Joined: 25 May 2016 Location: Derbyshire Status: Offline Points: 28 |
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Posted: 04 Apr 2018 at 11:24 |
Cutting a long story short a knowledgeable acquaintance who has never owned a Guzzi suggested the carbs on my T3 could be worn/worn out. They are the original pair fitted back in 1978, the bike has only done 36k miles, was stood for 20 years up to 2014 and has done little since to be honest.
What should I be looking for, can measuring the slide and body dimensions be helpful?
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Never pat a burning dog.
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Barry
Senior Member Joined: 02 Mar 2015 Location: Oxford Status: Offline Points: 2811 |
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"worn out" - What prompts that conclusion? If stood for a long while, then the carb surely could do with a little TLC - and that's relatively easy to do yourself with these carbs, not least because a superbly illustrated how-to is available here: http://www.thisoldtractor.com/moto_guzzi_loopframe_carburetor_rebuild_-__vhb.html
Pretty much everything is available for rebuilding / servicing these carbs (from Eurocarb, to offer but one source), and the fact that so many of them continue to do sterling service on Tonti roundheads (and some Loops?) speaks volumes. As I understand it, and I'm not a mechanic, the significant item that can be "worn" and sadly not replaceable (due to unavailability) is the slide itself. Unless someone has been particularly brutal with the carbs in the past, then 36K is small potatoes, and you might reasonably expect a lot more miles out of them. You could readily service them yourself, or get someone else to do so (perhaps getting them cleaned at the same time), or you could potentially replace with new 'round body' PHF30's, readily available from your regular Guzzi parts supplier. Me, I'd be looking to establish what "worn out" really means, and work from there. Like as not, they just want some love, some perishables replaced, and careful set-up. For my money, I reckon an inspection/estimate would, in the first instance, be a lot cheaper than a pair of replacements (which would still need setting-up for your particular machine). Edited by Barry - 04 Apr 2018 at 11:48 |
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jpc
Senior Member Joined: 06 Oct 2016 Location: Belgium Status: Offline Points: 651 |
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As above
180K miles on mine, experience beats "knowledge". Slides, being flat-faced, wear out even less than round ones. At most replace needles & needle jets, if at all, at that modest mileage.
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Ken-Guzzibear
Moderator Group Joined: 13 May 2014 Location: Sileby Leics Status: Offline Points: 9454 |
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To be fair spares for the flat slide carbs are running out they are well past sell by date .... The easy replacement are the round slide carbs as fitted to the T5850's and, with different jetting many 750's PHF I think but easy to check the ones with small triangular pump fitted do give a bit more go to the 850/1000's well worth swapping especially if you use your bike, by ALL means keep the flat slide carbs to pop on for and shows/authenticity ...not worth wearing them completely out. It IS the slides that wear quite badly they are the very parts you cannot get!
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The Older i Get, The Better I Was
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Barry
Senior Member Joined: 02 Mar 2015 Location: Oxford Status: Offline Points: 2811 |
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That's not been my experience, Ken. I have been able to get *everything* I need for these carbs, over the past couple of years, with the exception of the afore-mentioned slides. Eurocarb, and Gutsibits have been able to get me - without exception - any and all of the parts I've wanted. Granted, since they are a discontinued item, that situation won't always be the case. But then my T3 is a discontinued item in its entirety. (o; |
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jpc
Senior Member Joined: 06 Oct 2016 Location: Belgium Status: Offline Points: 651 |
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Ken, I'm really puzzled by that statement ! Unless perhaps another "improvement" was carried out by removing the breather box that brings some oil fumes to the carbs. The VHBs do have an accelerator pump in the main jet well, what is there to improve ?
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Dave P.
Senior Member Joined: 12 Jan 2015 Location: Northants Status: Offline Points: 5573 |
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Both of my Loops are fitted with VHB's.As was my Laverda GTL.They have given me no problems apart from having to abrade/polish out the indentations in the slides caused by the throttle stop screws.These indentations can cause erratic tickover but the fix is easy.Eurocarb have slides in stock for the 27-30mm range and for the smaller range as well as jets,gaskets etc.I'm staying with VHB's untill I encounter a real problem.
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TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.
1971 V7 Special. 1972 850GT. 1970 T120 Bonnie. 2009 500 Bullet. |
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cyclobutch
Senior Member Joined: 08 Sep 2015 Location: Essex Branch Status: Offline Points: 750 |
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They surely aren't worn out. Worst case might be the jets opened out by impurities running through them in the fuel. Swap out the jets for new every 30k-40k miles and keep on riding. Swap the 'choke' (enricher) plungers every 10k-20k miles.
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Butch
V50 II - 'The Black Pearl' T3 - 'Blue' Eldo Loop - 'Jug' |
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ranton_rambler
Senior Member Joined: 13 Feb 2015 Location: Stafford Status: Offline Points: 1147 |
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I'm also running VHB's on both of mine - 29's on the loop, which has done 46k miles, and 30's on the Spada which has done 35k miles.
No issues with starting, idling or fuel consumption. When I bought the Spada it had been standing for 15 years so I stripped both carbs, cleaned and fitted new seals. They do like to be balanced properly in my experience. I use a pair of Davida gauges. A common issue is fuel leakage past the cold-start plungers. Easily fixed by new plungers from Eurocarb.
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Jerry atric
Senior Member Joined: 24 Nov 2014 Location: Wiltshire Status: Offline Points: 3367 |
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50,000 miles on my VHBs, they are fine. The only thing on my Cali that is really past its sell by date with no available spares is the plonker on the seat
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Ken-Guzzibear
Moderator Group Joined: 13 May 2014 Location: Sileby Leics Status: Offline Points: 9454 |
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folks the vthou is 250k miles plus.....As has been said parts are available and slides will be fine for a few k miles Your bike your choice .... Not bothered about winning prizes ...the Vthou simply works ..... Not going to get into any argument about how this or that simply the round carbs work better ....got my info from Guzziology, followed that advice it is usually good advice ....
Edited by Ken-Guzzibear - 04 Apr 2018 at 19:30 |
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The Older i Get, The Better I Was
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johnno
Senior Member Joined: 19 Jul 2014 Location: loughborough uk Status: Offline Points: 5582 |
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Oh Ken I got round and square carbs they both work sound but then again I ain't done 250 000 miles on my bikes Ken when we out riding it's been a few years now
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1100 sport corsa , Yam R1, guzzi 650tt rider
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theone&onlymin
Senior Member Joined: 14 May 2014 Location: United Kingdom Status: Offline Points: 2072 |
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I may have .
Still on the VHB30's Still rockin' Cheers Min |
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Ken-Guzzibear
Moderator Group Joined: 13 May 2014 Location: Sileby Leics Status: Offline Points: 9454 |
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Johnno free ride in weekend at The Rockbar 13-15th bands Fri & Sat night...camping or local hotels see flyer on my facebook page mate My vhb's have been refurbished but off the bike as the round un's work better better acceleration and holds m way speed better especially 2 up and fully loaded ....I actually found the info in Guzziology, Ray has put the newer ones on his Spada, one other advantage is much lighter throttle pull due, I am told, to the effect of vacuum on the flat slides .... the old carbs work fine and will do so for oodles of miles ....nowt wrong with 'em at all .....
Edited by Ken-Guzzibear - 05 Apr 2018 at 11:47 |
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The Older i Get, The Better I Was
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Cylvabirch
Senior Member Joined: 02 Jun 2014 Location: Whitehill Status: Offline Points: 274 |
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When I overhauled the VHBs on my old T3 Cali the best bit of information I picked up was to spend as long as it takes to get the float height right.
After that all the adjustments worked beautifully. Before that it was a nightmare! An experienced Guzzi man told me they were “worn out”. They weren’t. |
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