VF400F restoration

So, no turning back now, i am doomed I will post the progress in this thread.
Seller found the registration book. The manufacturing date is 1986, type is VF400F.
The mark on the side of the cylinder is ground out, so I don't see the ccm marking.
Engine number is NC13E2005125. Is there a database to check for the proper type?
Anyway. To get it back on the road I need to put it back to MOT ready state and make it through the hideous administration.
Headlight is "made in Czechoslovakia"

 

Ok, its truly a 400ccm
VF400FD 1983 400 NC13E-2000008~2005685 NC13-2000001~2005685
43k in the clock.

 

It has 4x VB carbs. There is no mixture screw at all?
... edit, ah ok its in the manual.
What I learned so far with my bike is that proper carb boots are very very important to avoid vacuum leak. These are not factory original boots.

 

Hi, for about $15 you can get boots that will work plenty fine for your bike on EBay. There is another forum dedicated to the 400's however it is not as busy as it used to be...
Let me see if I can get some info for you.

 

Can You please give me a link to the boots and the other forum?
Found a set of carb bowl gaskets for cheap.

 

That bike looks like a hybrid of a 400 frame/engine with VF500 wheels/brakes. The tank is off the 500 too. A 400 had the inboard ventilated brakes and differently designed Comstar wheels. Good luck with the restoration, I owned a couple of 400s and the 500 when they were new, and liked them a lot. That 400 was a truly capable machine for its size.

 

Should i have misgivings about this blued conrod bearing found in the parts basket?

 

I could not find a topic where interchangeability of VF400 with VF500 parts are collected. Or VF400 parts with any other motorcycle parts maybe?
In particular, i am looking for a cheaper source than cmsnl.com for conrod and crank bearings?

 

Just finding a source for the sizes you may need will be the biggest challenge, let alone cheapest. Likely they will be one of few options.

Most parts sites have a "where used" function to check interchangeability on items. But with Honda, if the they are same part they will have the same part number, so you'll know if it's available.

This whole thing should give you "misgivings".

Good luck!!

 

Between the 3rd and 4th carb rebuild, cleaned and checked the oil pump. All tolerances within specs but there are some scratches. Oiled and put away in a plastic bag. Obtained the manual for VF400F

 

Now compared the VF400 and VF500 crank dimensions in the manuals. VF400 bots ID is 33mm, the main bearing on VF500 is 32mm.
I am thinking of getting VF500 big end bearings for the 400. Two dimensions missing. Bearing width (this is probably the same) and bearing thickness or conrod big end diameter.
Does anyone have data on VF500 conrod big end diameter?
One more interesting thing to get it more complicated. Cmsnl makes a difference in front and rear conrod bearings for the 500, however no such indication in the 500 manual.
Anyway, put back the front end and sat on the bike ... imagined riding it
Keep looking for possible bearing substitutes.

 

Ok, this is weird! Cylinders are 60mm (vf400 has 55mm, vf500 has 60mm) but crankcase number start with NC13.

 

All the engine internal parts are from a VF500. Moreover, the crank is from an 86 model (conrod journal is 33mm).
Outside the case thermostat housing is also from an 500.
Anyway, the crank is crap. Repairing it would be to much cash. Found a 85 model crank and conrods for sale. They got the same main bearings so a swap is possible.

Cleaned the carbs. Next i will rebuild the forks, seals already bought.

 

Here is a link to my picture collection about this project. Will add pictures with progress. Manuals for VF 400-500 also included.
https://www.dropbox.com/sh/3kyuno6k86wmnpo/AAA4-pGfyyPox9JjFIVzGzAAa?dl=0

 

Today's topic: valve stem seals.
Starting at cmsnl.com it seems that the seal for vf500f fits other 552 bike models. This is strange because the intake and exhaust stems are different in diameter. Or this difference is negligible and/or will be the same, since exhaust valves expand more by the heat?
There is a seller on e-bay offering the seal for the intake and exhaust separately.
If this seal is so common (552 models use it) is there a substitute for the original? Any known part number ID?

 

Parts arrived from the USA. Crank, rods, pistons and all the bearings. They look like new! Put the main bearings in the case and big end bearings in the conrods and let them measured in a machine shop. Oil clearances are 0.05mm. One pair of conrods had the caps switched resulting in 0.10mm clearance on one big end and 0.00 clearance on the other. After switching the caps back it was fine. No the engine is ok up to the pistons.
The pistons, however, are 0.50 oversize. According the machine shop guy the cylinders need no machining so i can use the old pistons with the rings from the oversize pistons. Of course, i need to check the ring gaps.
To the valves. Intake valve guides ar ok, but the valve face on the valves are worn. However, in a machinist book and also according the machine shop guy the intake valves are not that sensitive to the margin. So i can just grind the faces and lap them again. On the contrary, the exhaust valve faces are not worn, but they are loose in their guides. Replacing 8 exhaust valve guides would be around 100Euros from cmsnl.com. Any cheaper source for valve guides?
On the picture from left to right: lapped exhaust valve, non-lapped exhaust valve and a non-lapped intake valve.

 

Soda blasted pistons

Now it is a perfect time to repaint the case. The question is if i should strip the old paint with aluminium-oxide blasting (which would make a perfect surface prep) or just scrub the old paint and add few more layers. Some say that that engine parts should not be blasted allowing no chance for particle remains in the oil passages. It seems reasonable to to put the empty case together with side and valve covers and cylinder head (this will prevent media to get into the oil passages) and blast the whole thing, then paint them separately. Watched some awesome videos of VTN carbon application with clear coat. Thinking of using something fancy at least on the valve covers.

 

Clean/scrub and shoot. Honda paint is the best primer. Done it many times. Spend your time on the covers like you say.

 

Got a quote from a machine shop for valve guides. 125 Euros for 8 guides. I would prefer the domestic guides to the cmsnl original parts. However, its just a simple tube so i might give a try to hand turning. Important is that the outside and inside are parallel. The inside diameter will be reamed to the size of course. Question is how much a reamer can take away? Can i make the drill with a 4.9mm for example?
Anyway, next step is to take one guide off the head for measurements.

 

Got new heads from the USA, did not check yet, but they are from the same bike where i bought the crank and conrods.
Preparing for case assembly and i noticed that the transmission bearings having no locking pin, the outer race can creep in the housing. The driveshaft bearing on the sprocket side developed deep scratches. Just curious, why are there no locking pins?
I will lock them with Locktite 648.