SR2 rebuild, no fuel to piston

[Honkeyboy]

Hi all, i have just bought a Simson SR2e and am in the process of rebuilding it. so far most things have gone ok apart from the carb, which looks like has seen alot of abuse the spacer was broken at both sides and had been over tightened resulting in bending the carb mounting and the top had been hammered in again resulting in damaging the pin. i have done my best to rectify this but the carb still is not delivering fuel to the piston. anybody have any ideas on this? would i be able to fit a modern carb? ps i did prime the head and the bike started and run for a few seconds witout problem Thanks in advance for any help

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[subfossil]

Like a Harley

[Honkeyboy]

Thanks subfossil i wanted to scare the big boys

[SR2_Berlin]

Looks like mine :-)) But your handlebar is awesome!



(now a bit more used after two years almost everyday use and thousands of kilometers in Berlin city traffic). But now i moved to Frankfurt and the SR2 has nothing to do anymore

You have to look for an only slightly bend carburetor and then whet it with whet paper on a glass or metal plate. Don't know if anything more modern fits...

[Honkeyboy]

Thanks SR2 Berlin love your bike ive been looking into maybe fitting a walbro carb with a fuel reserve bottle for the outlet to possibly increase the power output a bit. As the City i live in has all crazy drivers so if i can power it up i can terrorise them instead and the carb was pretty badly curved i managed to straighten it out and fit new gaskets but still no fuel comming through, the back light you have used what was it from? looks really cool.

[SR2_Berlin]

hi, are you sure that the bended intake manifold is your problem? Could be a problem with the float gauge or something other with the carburetor as well. i ran into the same problem, if its bended too much, you will need another carburetor part.
you can use also a slightly bigger carburetor from the Simson Spatz, i will look after the number next time in my garage.
Where do you live? I assume not in Germany? :-) Mine ran with a bigger sprocket (17 teeth) 49 km/h measured by GPS. But only on flat ground, Berlin was flat enough... :-)
The back light is a quite common piece made in GDR, maybe for a trailer or so.

[Honkeyboy]

Hi again SR2_Berlin, no to be honest the carb isn't in the best of condition so agreed it could be some of the other parts internally. I hooked it up and its leaking from the tickle pin also when fuel goes into the carb so yes you might have a point with the float gauge i live in Lincoln England, the Spatz sounds like a good idea as parts are pretty hard to come by here. The mot is needed to register with DVLA so im trying to get ot running as quick as i can to get it registered. Thanks for the reply and help in this

[SR2_Berlin]

You need MOT also for 50cc bikes?! in Germany only an insurance is needee and off we go. :-)
Leaking from the tickle pin is not a good sign. This means either float gauge incorrect (too high) or pin valve broken, so fuel can always drain.
via Ebay or some Onlineshops (ddrmoped.de or ost2rad.de or sausewind.com) you should get some parts.
greets to England,
Victor

[Honkeyboy]

Hi again Victor, yes MOT's for everything here except pre 60's as with the Nsu Quickly i have in the first pic, the SR2 is 1964 so will need one but its not so harsh for any pre 77. I have taken your advice and have been out and removed the carb and stripped it down parts as per pic. I have as you suggested used glass paper on a flat surface and sanded down the inlet side which was still warped (pics to follow) and is now nice clean and flat, the tickle pin is complete but there looks as if there should have been a washer at the bottom of it which i will check against the diagram in a min otherwise although the internal parts are worn and old i have cleaned them up and am going to reassemble this afternoon. and hello to Germany ( i used to live in Munster in the 80's)

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[Honkeyboy]

and the carb inlet after sanding down.... Mark

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[Honkeyboy]

yes looking at the diagram it seems to be missing a spring from the bottom of the tickle pin so im going to see if one may fit from a ball pen as it looks about that size

[NorbertE]

Hi Honky, Yes, you can use a part of a spring from a ball pen. It works but I´m shure that is not the reason why your carb dos`nt work.

A little help (use a translator) is here:

https://www.ddrmoped.de/forum/index.php?showtopic=23035

[Honkeyboy]

Hi Norberte, i tried it today and your right it isn't, i rebuilt the Vergaser/carb and still no joy a bit of the problem is that one of the head studs had been drilled badly and messed about with i have tried to cold weld a new stud back in with no joy. and i think its drawing air in from the manifold. I did think of trying to fit a walbro carb as its lighter and it works differently but im slowly starting to think that this will also be a waste of time and money so i have been in contact with a guy on ebay.de for a replacement engine. the one i have i can strip for spares.and at 100 euro's with postage it is possibly the best plan. Either doesn't matter to me as i hold a full bike licence. the carb by the looks of it is shot and no good so that will have to go either way. I do want to increase the power so i can keep up with modern day English loonie drivers. I do love the looks of the SR2 its a very cool looking bike. sorry for the late replies it was my wife's 47th birthday today and we went out. thanks for your reply. Mark

[Honkeyboy]

i was tempted to try to find a 250 engine to fit but i think the British MOT inspectors would have a heart attack and send me home lol not type accepted they are just no fun here

[NorbertE]

So, so, a 250 engine. You are a suicide boy? The inspectors don`t send you home. They will send you in a madhouse.

Any ways are possibil to fit your engine with the carb:

-a used original carburator BVF 121-x from ebay. Its available any time and not so expensive.
- an other carb in example from BING or AMAL. This must have 12 or max. 13mm diameter airhole trough. You can use a modern air filter also.

You must be shure, that nothing of air is running in on the place between the carb and the block!! This engine works like a airpump! Also you must the carb isolate of thermic base on this place. In original the big plastic disc is the thermic isolation. Do not forget!

Both side (carb and block) must be exactly flat (air!) Look at the link, I`ve sended.

And of course, this problem with the head studs is`nt new.I also fixed on one motor one of the stud new with cold welding, with aluminium fluid based of 2 components. It works!
Show me a photo of this place on the block, please.