NC24 ENGINE REBUILD

[pagan1001]

oh yeah my valve clearances are set to inlet 0.10 and exhaust 0.20 this was done 2 months ago.

[Neosophist]

oh yeah my valve clearances are set to inlet 0.10 and exhaust 0.20 this was done 2 months ago.

Ok there wrong.

Inlets should be 0.11 - 0.15
Exhuasts shoudl be 0.18 - 0.22

I'd aim for 0.13 on the inlets and 0.20 (which you have on the exhausts)

The NC24 has 115 jets all around (have you changed these?)

Sounds like you might have NC21 cabrs.. these use different rubbers to the NC24 carbs, i've not intermixed a set before but there must be a reason why there different.....

I wouldn't worry about the float bowl gaskets.. if it leaks fuel there shot, if it doesn't there ok.

Float heights are fine.

I'd set the pilot screws to two turn turns out (compelte turns.. ie 360 degrees.. not HALF turns like some people do, i.e. if your pilot screw is horizontal when its all the way in.. half a turn make it horizontal again, another half a turn makes it horizontal again (1 complete turn))

[pagan1001]

so someone has swapped the carbs on my bike, what is the difference apart from the jets????
so if I put nc24 jets in then they should be the same as I have new rubbers nc24 ones from david silver. Why would they install different jets or is it a case of nc24, nc21 being very similar in carb set up that they thought they were the same.
No I did not do this but I had no way of know as I was going by haynes so glad you said or I would be none the wiser. Does david silver do jets?

[Neosophist]

so someone has swapped the carbs on my bike, what is the difference apart from the jets????
so if I put nc24 jets in then they should be the same as I have new rubbers nc24 ones from david silver. Why would they install different jets or is it a case of nc24, nc21 being very similar in carb set up that they thought they were the same.
No I did not do this but I had no way of know as I was going by haynes so glad you said or I would be none the wiser. Does david silver do jets?

They do.. but the NC21 has 110 / 112's in it as standard which makes me think they could be NC21 carbs.

What number is on the sides of the carbs.. it'll be VDE something if I remember.

I'll have to consult the gurus on this one.. the NC24 rubbers and NC21 rubbers have different part numbers.. this suggests to me that they are slightly different.

Now if you have NC21 carbs (quite possible) they may not seal properly on the NC24 rubbers and vice versa.. this could be the cause of your air leak.

If you give me the frame number ( I don't need the last couple of digits.. just the NC24-xxxxx part.) and whats written on the carbs i'll tell you if there the correct carbs for the engine.

It could have been that somebody has put smaller jets in it, but since they match NC21 jets its likely somebody has swapped carbs.

The 112 / 110 jets are fine for the NC21 carbs but you get a smoother power delivery with the NC24 carbs, top ends a little richer.

Do you sliders have rounded or flat bottoms? What numer is written on the needles.. all things like this will help

Best to put some slack in your inlet valves while your messing :-)

[pagan1001]

Will do just got a few things to do then will get these numbers for you okay been trying to find jets but no luck so far all I have found is a guy on ebay selling brand new nc24 carbs for £150 but maybe get him down on that but will check these numbers first cheers

[Neosophist]

Jets are easy to get hold.

David Silvers / Wemoto / Lings all do them.

There a standard Kehin Part.

99101GHB1150 is for 115 main jets.

http://www.cmsnl.com/honda-vfr400rh-ii- ... E16-1.html

Heres the parts list for the NC24 carbs.

It lists 112 as an option for early carbs (in fronts only..) *shrug* doesn't match my part books.

anyway.. with the frame number and carb info i'll be able to look up what should / shouldn't be in there and we can go from there.

Bigger jets arn't going to affect the idle though as they all use 35 idle jets and 6.8mm float heights.

[pagan1001]

Here Neo the carb number was hard to read but it has VD ON THE SIDE THEN E2CCBCE but the last letter might not be an E as it does look slightly different but thats the closest letter I can match unless its in japanese. Oh and the second C has a box around it if that makes any difference.
the frame number is NC241003066 cheers

[Neosophist]

Ok now were getting somwhere :-)

Yes it does make a difference being circles.

VDE2C are the carbs then (A-F) is the revision.

The very early ones A -> C had the smaller jets.

Although CMSNL lists

Upto Serial#: VDE2C-B

Then

From Serial#: VDE2C-D

Doesn't say anything about the C model.. hence me needing the book.

It sounds like you may have a very early NC24, which may have had 112 / 110's in it.. or according to CMNSL 115/112's

I'll check the book tonight and see if there right :-)

Going off the frame number its a very early 24.. 1987 RH-I by the sounds of it.

What color is it?

It should look like

http://www.cmsnl.com/vfr400rh-1987-japa ... q=VFR400RH

:)

[pagan1001]

Cheers and yeah thats my bike in the picture. So should I get 4 x 115 jets or leave it, as david silver has given me a price of £5.90 each. Or could I just change them all to 115 and see if it makes any difference?

[Neosophist]

Cheers and yeah thats my bike in the picture. So should I get 4 x 115 jets or leave it, as david silver has given me a price of £5.90 each. Or could I just change them all to 115 and see if it makes any difference?

That's a little pricey, can get them for about £4.00 each.

I wouldn't change them yet. Let me see if they are standard.

Bigger main jets arn't going to affect your idle as the jets are closed at idle.

Thats float height / pilot screw teritory.