Topic: For those who have swapped their 350f for a 400f

[treemagnet]

I bought the '73 350f a couple years ago with the intention of making a little cafe bike out of it. It always ran like crap for a couple of reasons. I took the top end off to find some horrible looking valves/seats and pistons/rings that needed replacing. I knew I'd like a 6th gear and a little more juice instead of dumping more money into the 350f motor. I finally found a 400f motor ($200) that the PO said he had rebuilt 6 years ago but never put back in the bike. I can see that the valves are new and the cases have been split and have new gaskets etc. We'll see how she goes once i get the motor mounted up and ready to roll.

Been riding for years but have not made the time to wrench as much as I'd like. I have a couple of questions if you'd be so kind:
1. are the points the same - I think yes. The "new" motor has no points in it now but i have some new ones for the cb350f that I'd like to use.
2. As far as carbs go - just change the slow jet to a #40 from the 350f's #35 right? BTW - should i be able to see daylight through this jet if I'm looking through it from end to end?
3  what did you do about the spacing/length of the foot controls? pedals, brake, shifter? The 350f smaller cases make a direct swap impossible? or just awkward?
4. Anyone use the 350f's 4 into 4 on a 400f? I have it and would like to run it and wondered 2 things - will it clear the motor/cases okay? and you think i need to rejet for them since the are not original 400f pipes?
5. The clutch cable - my searches tell me that it differs from 350f. If I am to buy one for $40 on ebay anyway, i thought I'd have one made to account for my lower clubman bars (might be clip ons one day but same length would work here). Any advise on clutch cable length?

Thanks. I can get some pics up of my first ever build tomorrow I hope.

[hoodellyhoo]

To answer your questions as best I can:

1) The points themselves are the same. I'm not sure about the points plate, but I'm pretty sure that's the same as well.

2) Correct on it being #40. It's been a while since I've looked at one but I'm pretty sure you should see daylight though it. As long as you're removing the carbs it might be a good ised to give everything a good cleaning if you haven't already.

3) Here are some pics of a 400 motor in a 350 Frame. The footrests have been moved back, possibly mounted like on the 400 (I dunno). They seem to have made a pivot for the shifter. The rear brake is certainly different (another 400f part?) I was able to kick the motor over once I moved that footpeg out of the way.

http://i158.photobucket.com/albums/t110/hoodellyhoo/019.jpg
http://i158.photobucket.com/albums/t110/hoodellyhoo/018.jpg




4) As long as you're using the 350 frame, I don't see why the stock 350 exhaust wouldn't fit. You would probably have to just experiment with the jetting and see what you get.

5) No clue. Like you said, the 350 and 400 cables are different but I don't know if it's just a matter of length or if their construction is a little different too.

Hope this helps

[treemagnet]

yeah, that shifter has some extra linkage that the 350f does not. I'll find one.

thanks for the other info. If anyone else thinks of something i should know for this project please chime in.
thanks

[hoodellyhoo]

the linkage and shifter are deffinitely from a 400

[treemagnet]

cool, thanks I have located the foot pegs, Motor mount bolt/foot peg bolt, shifter with linkage. all shipped for $50. sounds fair.
thanks

[kghost]

400 Right side peg folds up....to clear the kickstarter....dunno if you got that one too

[treemagnet]

good to know. it is coming from the same bike as the motor so it should work fine. never knew you had a fold up peg to clear the kicker. cool.

[treemagnet]

any more info on the points/points plate? I tried today to mount up the plate (with condensors and all installed) but the center hole seems smaller. Also the 350f "special nut" as refered to int eh manual is a size smaler than the 400f one - leading me to believe that the center hols on these ponys plates are different sizes. any more info would be great. researching now.
thanks

[Terry in Australia]

I restored a CB350F back in 1996 (beautiful bike, wish I still had it, BTW) and from memory, the points plate is the same for the 350F and 400F. I just checked the Cycle/Recycle website and they quote the same part number for each, so I think you're pretty safe. Post some pics of that bike mate. Cheers, Terry.

[kghost]

RE: the clutch cable.

Yeah they are different.

They have a different mount system and they have different adjusters on the clutch end.

350F has a bracket and the 400 has a hole in the clutch cover (the 400 is more like the 750)

Now.....

I was missing the Adjuster on my 400 and some idiot had screwed up the threads in the clutch cover.

What I did was retap the cover on the 400 to use the adjuster from the handlebar lever.

Now the 350F cables will work on my 400 minus thier adjuster. So will the 750 cables.

[fmctm1sw]

Somewhere I read that the engine case is wider necessitating the gearshifter being the way it is (with the added linkage).  I don't think its possible to run a 350F footpeg/gearshifter setup on a bike such as the one you are creating.  I thought I read that somewhere on here.  I had this idea a while back until I realized the crankshaft in the 400F engine I had was siezed.  However, according to the fische, the crank is the same as the 350F.  Kind of wish I didn't sell the functioning cam chain tensioner assembly now...

[treemagnet]

All great info. thanks guys. I will give it another go tomorrow. Maybe I was just not going about it the right way today. I was sort of in a hurry and when it did not fit, I gave up a little prematurely perhaps. Any tips to change the points plate with points would be helpful.
I'll try to get some pics up asap. Will take some soon.
thanks again.