NC21 Carbs

[jambofvr400]

Hi everyone, just a question about the NC21 carbs really. I have done a search but the resulting posts were so old that the diagrams/photos etc are now gone

Basically, I have stripped my carbs down, cleaned them and rebuilt them. Unfortunately in the process I buggerd one of the throttle plates. Mine are the 30mm ones that have no velocity stacks on them.
I bought a spare set of carbs off ebay which were labelled as NC21 VFR400 carbs. Upon reciept, these are bigger than mine and are 32mm ones so i can't get the plate I need. These ones also come with velocity stacks.
I have spent ages cleaning my original ones and as they came already on the bike I'm reluctant to fit the other ones. Having done a bit of research it seems the 32mm ones will work and were on some of the NC21's, just not my one for some reason.

Does anyone have a spare 30mm throttle plate lying around I can buy off them please?
Once these carbs are sorted its ready for firing up for the first time (good compression on all 4, no signs of any other issues at the moment).

Cheers

[jambofvr400]

Or if anyone knows where I can buy them online please?

[Neosophist]

how far did you strip them? you dont really need to get throttle plates out, even when disassmebling the carbs.

iirc they are aluminium? you could get some alumining sheet the same thickness and cut and tap one if you have tools, if not youll probably have to buy a new set of carbs, they dont sell them separatly.

[jambofvr400]

Thanks for reply mate.
I didn't want to take the plates out but in this instance I had no choice as the whole shaft had corrosion preventing them from operating. I had to remove the plate to then slide the shaft out and clean, polish & loob it up.
I think I'll have to just make one like you say

[Neosophist]

Thanks for reply mate.
I didn't want to take the plates out but in this instance I had no choice as the whole shaft had corrosion preventing them from operating. I had to remove the plate to then slide the shaft out and clean, polish & loob it up.
I think I'll have to just make one like you say

if they were corroded has water gotten in there?

If so what is the state of the valves / pistons / bores?

[jambofvr400]

Only a bit of water has got in it seems, there is slight corrosion/build up of browny mayonnaise on the top of the valves but I have done a compression test and good strong compression on all 4. I think where it has been sat for so long on a tilt the moisture has built up and gone into that carb. The other 3 aren't as bad at all. I was going to make sure all valves are closed then blow it all out with air line.

[Neosophist]

if you have rust on the back of the valves it wont seal right and youl have to get the valves out and clena them up, ive had to do that on a zxr engine before that had pitted valves from rust.

hopefully its not so serious.

[jambofvr400]

Ok I'll check thanks.

If I get no-where with this bent throttle plate, can I just fit the other carbs I got off ebay? Despite the fact they are bigger (32mm not 30mm)? Surely they won't match up to intake ports though? they have come of an NC21 though so I have no idea

[Neosophist]

you will need later carb rubbers off an nc24 / nc30 (They are about 5 pounds or so each in uk money) dont waste time with second hand ones, muhc trouble and money than its worht.

you can bolt later carbs right on.

[jambofvr400]

ok brilliant thanks for that I'll just do that then :)