Chinese carbs on G5 - need info

[crabbymoto]

My carbs are the original 30's and worn out.  I've searched and found references to people having good luck with some of the Chinese knock off carbs but only references not which ones and which manifolds.  I'd love to put new dellorto's on, but the funds don't allow right now.

Anyone have good recommendations for carbs and where to get manifolds to properly install?

It's a bone stock 1980 G5 V1000.  See pics for carbs and manifolds.

Thanks for any help!!!!

[Scout63]

Those carbs look pretty good.  Are the slide housings worn?  Vapor blasting and new floats,  jets and gaskets and maybe you are in business.  Then again all of that from Dellorto might cost more than new carbs.  I would avoid knockoffs. Best of luck.

[Canuck750]

You could contact SUDCO - the Mikuni carb supplier and ask if they can reccommend a type of Mikuni and the reccommended jetting.

I have a Moto Morini 500 that the prevous owner fitted with new Mikuni carbs from SUDCO, he gave them the motorcycle make and model and motor type (V twin, air cooled), the displacement, bore and stroke, claimed horsepower and they provided complete carbs jetted, and they worked very well out of the box, I had to change pilot jets due to my location / altitude, carbs were set up for sea level.

sudco@sudco.com

[cliffrod]

All i can say is that pay for what you get. 

China carbs might work ok as shipped.  Good luck. You might only have to spend 2-3 hrs per carb to make it possible to install real Dellorto or mikuni jets & such to make it actually operate better than the worn out carbs you have.  Btdt.  If you are only having tuning issues with your dellortos and cannot sort them, odds are that the China carbs are probably going to be just as if not more trouble.   If they wear out prematurely, oh well...  And when you sell the bike (or keep it forever) you'll have lots of opportunities to explain to either buyers or peanut gallery members why you ditched good carbs for those non-original parts that won't help resale value.

A pair of dellortos or real Mikunis from Sudco will be much better money spent imho.

[guzzisteve]

How many miles on bike 200,000, I can't believe they are shot.

Charlie at Antietam Classic Cycle has the info you need on the Chinese ones.

[Antietam Classic Cycle]

Those carbs look pretty good.  Are the slide housings worn?  Vapor blasting and new floats,  jets and gaskets and maybe you are in business.  Then again all of that from Dellorto might cost more than new carbs.  I would avoid knockoffs. Best of luck.

I would not replace the floats - all that's available (unless NOS) are the crappy white ones. Unless the original floats are filling with gas, keep running them. I also would not vapor blast - the media (however fine) may plug vital passages. Soda blast, maybe. 

How many miles on bike 200,000, I can't believe they are shot.

Charlie at Antietam Classic Cycle has the info you need on the Chinese ones.

Agreed. What is "worn out" about them?

"Credit where credit is due."
mtiberio installed a set of Keihin PWK copies to his Eldo using manifolds from an Eldo originally equipped with Amals and these carbs (or a similar set) meant for a Triumph. Paul Linn did the same on a California II.

[guzzisteve]

Thanks Charlie, I was thinking it was you, Mike may be racing. I can't keep all this info strait anymore, should have done a search. BUT I knew you know about it.

[Antietam Classic Cycle]

This might provide some useful info. as well:
https://www.thisoldtractor.com/moto_guzzi_loopframe_carburetor_swap_-_replace__vhb_with_mikuni_vm.html

[crabbymoto]

Thanks everyone so far, to try and address different questions.

Bike has over 80,000 miles on it.  Are they fully worn out, could they be rebuilt?  Probably.  But I'd like to go to a larger carb anyways.  I have a good friend/mc mechanic who has used the Chinese knockoffs on other type bikes, Triumph 650 and Evo Sportster, and had success with them.

It's also a chance to somewhat inexpensively see what larger carbs can do. (I know there are arguments on both sides about the performance gain from a larger carb, but I'm willing to try.  Not looking for a drag bike but a little more oomph is always good)

 I'll check with sudco, but my feeling was those mikuni's would get up toward the cost of dellorto's, and not be as pretty :). I'll check with them anyways.

Was hoping to find a "get these carbs and this manifold" but sounds like it's more exploring and figuring it out.  Which is totally fine too!

[huub]

i run chinese Vm34 mikuni's on my v65 lario,
those work just fine.
of course you will spend some time jetting them.
if you find manifolds for a guzzi with PHF carbs the mikuni's will simply fit.
i never tried with the solid manifolds of the G5, so that might, or might not work

[Gliderjohn]

Have you looked for a good used set? Should be some out there.
GliderJohn

[Scout63]

I have a brand new pair of PHF 36s whispering to me from the shelf, and Guzziology gently but firmly telling me to keep them away from the G5. Now maybe if I had some Lemans heads and a B10 cam...

[Chuck in Indiana]

I have a brand new pair of PHF 36s whispering to me from the shelf, and Guzziology gently but firmly telling me to keep them away from the G5. Now maybe if I had some Lemans heads and a B10 cam...

Yeah, I don't see the point of putting larger carbs on the small valve engine.. and Shirley  80000 mile carbs just need freshened up..

[jwinwi]

Your VHBs may need new needle jets; they get hogged out by the needle after a while and the result is a too rich mixture. BTDT...
Is this what you are experiencing?

[Tony F]

I have a brand new pair of PHF 36s whispering to me from the shelf, and Guzziology gently but firmly telling me to keep them away from the G5. Now maybe if I had some Lemans heads and a B10 cam...

The 36mm carbs can be made to work just fine on your G5 with a bit of work to open the inlets to match le mans manifolds and careful jetting. But be aware that at 80,000km the valves and guides might be due some attention. According to P Roper the shape of the back of the small inlet valves is very conducive to gas flow and these heads can be made to flow very nicely.

[crabbymoto]

i run chinese Vm34 mikuni's on my v65 lario,
those work just fine.
of course you will spend some time jetting them.
if you find manifolds for a guzzi with PHF carbs the mikuni's will simply fit.
i never tried with the solid manifolds of the G5, so that might, or might not work

Thanks for the info!

[crabbymoto]

Your VHBs may need new needle jets; they get hogged out by the needle after a while and the result is a too rich mixture. BTDT...
Is this what you are experiencing?

Maybe. the bike just feels a little sluggish off the line and at low revs. when giving it gas.  But feels like there's more there and ready- it's just not getting what it needs, if you know what I mean.

I know it's a 41yo rather heavy bike, but I think the carbs/throttle response can be better.