Hello All,
Time to refurbish the Mikuni VM 32 carbs on my 750 J model. What should I renew and where do I obtain them in the UK? Would Allen's Performance near Nottingham be able to obtain the parts do you think?
Also should I renew the intake stubs number 13110-32200? Have you seen the price of these!!!!!!!!! I notice online that the stubs now have a slot/recess in the round end which my (originals?) do not - anyone know why this is?
RogerH.
Carburettors (J)
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klektermaniac
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barney01
- Posts: 3120
- Joined: Wed Sep 26, 2012 7:33 pm
- Location: Prestatyn.Wales
Re: Carburettors (J)
It's up to you what you replace. Is the bike running well? Maybe just a good clean out with an ultrasonic cleaner would suffice.
Deffo replace the float bowl gasket though.
The one thing to make sure is that any replacement jets etc you do buy are genuine Mikuni I use NRP in Liverpool.
Reference the carb to cylinder rubbers. These have to be in good condition and flexible to seal properly. Any cracks or hard parts will allow air in and lean out the mixture. This could end up with a holed piston so although expensive it may be a worthwhile investment for peace of mind. You can try to soften old rubbers with wintergreen oil if necessary
If you have a J model then the rubbers have a slot in the front to locate on a stud on the carb
Deffo replace the float bowl gasket though.
The one thing to make sure is that any replacement jets etc you do buy are genuine Mikuni I use NRP in Liverpool.
Reference the carb to cylinder rubbers. These have to be in good condition and flexible to seal properly. Any cracks or hard parts will allow air in and lean out the mixture. This could end up with a holed piston so although expensive it may be a worthwhile investment for peace of mind. You can try to soften old rubbers with wintergreen oil if necessary
If you have a J model then the rubbers have a slot in the front to locate on a stud on the carb
Last edited by barney01 on Sat Jul 20, 2019 6:59 pm, edited 1 time in total.
NO SMOKE .......NO POKE
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mizzytheman
- Posts: 2227
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- Location: Knowsley, Liverpool
Re: Carburettors (J)
Motocarb in Liverpoolbarney01 wrote:It's up to you what you replace. Is the bike running well? Maybe just a good clean out with an ultrasonic cleaner would suffice.
Deffo replace the float bowl gasket though.
The one thing to make sure is that any replacement jets etc you do buy are genuine Mikuni I use NRP in Liverpool.
Reference the carb to cylinder rubbers. These have to be in good condition and flexible to seal properly. Any cracks or hard parts will allow air in and lean out the mixture. This could end up with a holed piston so although expensive it may be a worthwhile investment for peace of mind. You can try to soften old rubbers with wintergreen oil if necessary
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barney01
- Posts: 3120
- Joined: Wed Sep 26, 2012 7:33 pm
- Location: Prestatyn.Wales
Re: Carburettors (J)
Yes sorry motocarb Liverpool http://www.motocarb.com/mikuni-main-jets.html
NRP Manchester http://www.nrp-carbs.co.uk/shop/index.p ... on/contact
NRP Manchester http://www.nrp-carbs.co.uk/shop/index.p ... on/contact
NO SMOKE .......NO POKE
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klektermaniac
- Posts: 92
- Joined: Sat Oct 25, 2014 8:54 am
- Location: Lincolnshire
Re: Carburettors (J)
Thanks for the replies.
I bought this bike as a restoration project but wanted a complete bike however bad some items were, and as such it has never run in my ownership. This is why I wish to know what to replace in the carbs as a matter of routine as I have no idea how it performed and what is worn in the carb area.
However when I stripped it the Left piston had a 3 centimetre bite out of the front edge at the 10/11 o' clock position when viewed from the rear - obviously no idea what caused this - but the engine was in a pretty grotty state although it had done around 25K miles.
Yes mine is a J but my carb rubbers do NOT have this slot - have they been modified over time?
RogerH.
I bought this bike as a restoration project but wanted a complete bike however bad some items were, and as such it has never run in my ownership. This is why I wish to know what to replace in the carbs as a matter of routine as I have no idea how it performed and what is worn in the carb area.
However when I stripped it the Left piston had a 3 centimetre bite out of the front edge at the 10/11 o' clock position when viewed from the rear - obviously no idea what caused this - but the engine was in a pretty grotty state although it had done around 25K miles.
Yes mine is a J but my carb rubbers do NOT have this slot - have they been modified over time?
RogerH.
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barney01
- Posts: 3120
- Joined: Wed Sep 26, 2012 7:33 pm
- Location: Prestatyn.Wales
Re: Carburettors (J)
So have you replaced the damaged piston? Have you found the missing piece? As I said before the carb jets and parts may be okay and just need a good clean. Until the engine is running you won't know.
It sounds like you have the wrong carb rubbers and new correct ones would be my first purchase.
It sounds like you have the wrong carb rubbers and new correct ones would be my first purchase.
NO SMOKE .......NO POKE
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Alan H
- Posts: 12110
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- Location: Wombwell, Republic of South Yorkshire
Re: Carburettors (J)
Baz on here refurbs carbs properly with genuine Mikuni parts if needed, not aftermarket stuff.
Proof that four strokes are over complicated
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klektermaniac
- Posts: 92
- Joined: Sat Oct 25, 2014 8:54 am
- Location: Lincolnshire
Re: Carburettors (J)
Hi,
Yes I have done a full engine overhaul - new mains and seals, rebore, pistons, etc, etc.
Will try to do the carbs myself - I have access to an ultrasonic cleaner - and probably replace all needles and jets etc with genuine Mikuni as a matter of course. Also now I have cleaned the inlet stubs properly I can see they are full of small cracks when stretched, so will definitely have to have 3 new ones. Will most likely obtain thro' Robinsons and get a little discount.
Thanks for the help.
RogerH.
Yes I have done a full engine overhaul - new mains and seals, rebore, pistons, etc, etc.
Will try to do the carbs myself - I have access to an ultrasonic cleaner - and probably replace all needles and jets etc with genuine Mikuni as a matter of course. Also now I have cleaned the inlet stubs properly I can see they are full of small cracks when stretched, so will definitely have to have 3 new ones. Will most likely obtain thro' Robinsons and get a little discount.
Thanks for the help.
RogerH.
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BAZ
- Posts: 3599
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- Location: Dudley west midlands
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Re: Carburettors (J)
if you send the Bodies to me I can get them Vibrato/de bur cleaned, you may find the original jets are ok just need gaskets..
https://www.youtube.com/watch?v=7sWW0dYiqIE
https://www.youtube.com/watch?v=7sWW0dYiqIE
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klektermaniac
- Posts: 92
- Joined: Sat Oct 25, 2014 8:54 am
- Location: Lincolnshire
Re: Carburettors (J)
Hello,
Sorry to come back to this but have been away for a couple of weeks.
Your replies suggested I use only genuine Mikuni parts, but what about these Keyster kits? Are they any good or not? As long as they are machined to the original specification surely they will work OK, and my bike will never be doing the distances it would have done back in the day.
I see that the two recommended Mikuni suppliers sell these.
Your comments would be appreciated.
RogerH.
Sorry to come back to this but have been away for a couple of weeks.
Your replies suggested I use only genuine Mikuni parts, but what about these Keyster kits? Are they any good or not? As long as they are machined to the original specification surely they will work OK, and my bike will never be doing the distances it would have done back in the day.
I see that the two recommended Mikuni suppliers sell these.
Your comments would be appreciated.
RogerH.