Clogged heat riser tube stock 1200 Bug

Hi guys,

Has anyone ever had problems with their 1200 manifold heat riser tube clogging up with black carbon?
I have tried cleaning it out with everything I can think of but, cannot get it clean.
It is only the heatriser tube which is clogged and this is causing icing around the carburetter and of course the bug hesitates and just is'nt running right!
Takes forever to warm her up before I can drive up my street 😠
Is there anyone who can help with cleaning these. I tried a local engine builder but he could'nt acid bath it because of the cast alloy sections.

Cheers

Greg

I think you can buy new ones??? from Vintage
does your choke work???
I have seen people rig up a hot wire around manifold, bottom of carby does same job as heat pipes.
I have Beetles with and with out heat riser pipes , they all start and go ok on very cold mornings??? eg Katoomba mornings😂 The only problem at Katoomba i cant see out the windscreen cause of the fog inside the car🤪

Greg,

Here's Rob and Dave's un-blocking heat riser procedure from their VW-resource website.

http://www.vw-resource.com/heatriser.html

They use a piece of old clutch cable, frayed at one end, in a drill. If it's really blocked you might want to start first with a piece of speedo cable (not frayed), or even some stiff fencing wire, then change over to their method.

Regards,

Matt.

i once unblocked one with a bit of stainless cable i had lying around , put it in the end of a drill and drilled it out......carefully! i shredded my hand when the cable came out and whipped around. need a bit of cable of reasonable diameter so that it dosn't flex too much. have heard that acid poured down the tube works...didn't really work for me, and oxy torch down the end was another i read about somewhere,
prob. safer and less agro to buy a new one.

the only way to fix is to cut or drill a hole near thebends and drill the carbon out using a long series drill

Or if you can find a new one buy one as theres about a good 10 hours work in fixing a blocked heat riser

try break fluid just keep putting more in over a week till it eats it's way down
thats with it off and upside down

try break fluid just keep putting more in over a week till it eats it's way down

It will be SOLID just like coal brake fluid wont touch it only a tipped drill bit

ive cleared a pretty blocked one before by drilling out the first bits of the pipe then leaving it upside down filled with a really harsh industrial degreaser called active-shift for a few days

flushed it out with the garden hose, clean as inside after that

Thanks guys, 👍

I did try the stainless fencing wire in the drill method and had some success but the middle part below the carburetter is just rock hard. I just had a look at the link you provided Matt... I never thought of pouring some carb cleaner in or strong degreaser to soak before trying the wire again... I have been keeping an eye out for a new manifold but I think they're getting like rocking horse pooh to find! I have checked the auto choke and it's doing what it should... Lastime I tried cleaning it out, it did run well again for a while so I'll have another go and let you know how I do this time

Cheers

Greg

Mountains Greg wrote:Hi guys,

Has anyone ever had problems with their 1200 manifold heat riser tube clogging up with black carbon?
I have tried cleaning it out with everything I can think of but, cannot get it clean.
It is only the heatriser tube which is clogged and this is causing icing around the carburetter and of course the bug hesitates and just is'nt running right!
Takes forever to warm her up before I can drive up my street 😠
Is there anyone who can help with cleaning these. I tried a local engine builder but he could'nt acid bath it because of the cast alloy sections.

Cheers

Greg

My 1500 single port manifold rusted thru... had it welded up but it wasn't long before it blocked up...
Carby iced up badly last winter....

I bought another manifold in nearly new condition from
Stokers siding garage 02 66779246 last year

A = hot air pick up tube
B = electric blanket 12V

LEE