Down under, an idiot and a 400F

[neevo]

Great community input on the rake and the way to get it right. Like having a baby then not having to take care of it because you know the state will do it for ya ??? ;D :-X.

Are you suggesting I'm being lazy?

 

[DohcBikes]

Are you suggesting I'm being lazy?

Nope, i'm suggesting that im too lazy to explain things that I point out, but others are there to pick up the slack. it works out great.

 

[neevo]

Nope, i'm suggesting that i AM lazy.

Ahaaaaaaaaaa. Gotcha. Make a comment... Let the community solve it.

That's exactly what this place is for isn't it

Fuck you though (in the nicest possible way)! You've now got me thinking about bracing the frame properly, making a fuel cell and cutting up an old tank for an outer skin like the link above.

 

[DohcBikes]

Fuck you though

That's the nicest thing anyone has ever said to me.

You have compiled lots of good parts man, i'd like to see them used to their potential. A USD front has great potential to either improve or reduce performance. As does almost any mod. When you have money into it, the time is owed.

 

[neevo]

Do it properly or not at all. Shame as it keeps getting deeper down the rabbit hole.

Bracing and fuel cell would solve front end handling and my coil to tank clearance issue though!

 

[doc_rot]

Do it properly or not at all. Shame as it keeps getting deeper down the rabbit hole.

Bracing and fuel cell would solve front end handling and my coil to tank clearance issue though!

this mode of thinking is my problem as well, once you open that rabbit hole its hard to not go nuts.

That 400f you posted may be the coolest I have ever seen. If you want to get the most strength to the head stock you will need to triangulate the frame like they have, or if you want to get crazy with it you could completely cut out that stamped steel back bone and do a large diameter tube like the old EGLI chassis.

 

[jpmobius]

Far be it from me to discourage any sort of performance upgrade. That said, I often find it useful to take a few steps back look at the big picture. The 400F is, stock, a really well thought out and very friendly handling bike. Keep this in mind! There is no question that you can get more out of it, but it comes with a price, and sometimes it pays to think a bit conservatively to keep your drive for performance from spiraling out of control. Suspension upgrades? great idea. Geometry changes? My opinion is that a little goes a long way. You can steepen up the rake for example, which will have (depending on who you ask) potentially good consequences. But it WILL come with a price. This is where attempting to brace the frame (this is so far away from amateur hour I don't have a description) to enable good use of the steeper geometry becomes relevant. My opinion is this: If you didn't ride around on you bike and after doing so said to yourself "gee, it really needs more ____ or less___, so I ought to change ____ to make it drive more like what I want", why in the world would you want to alter the geometry? More modern bikes have much steeper geometry than your old 400, but the makers have very massively strengthened the chassis to absorb the problems that arise from doing so. It will be quite a project to paste some reinforcement on the old 400 frame to bring it's natural frequency into line with modern geometry, but even if you could, is it really a benefit? Will you actually realize the benefit driving it around? You have made some very comprehensive changes already. I would make every effort to make an initial setup as close to stock geometry as possible. The short offset you have will add some trail, but you can always take some rake away to compensate if you think it too lazy. Set it up as close to stock as you can, start driving it around, and sort out the suspension. With the changes you have made, that will take some doing even if you are well experienced at doing so. THEN make changes to fix what you don't like about the way it drives. By the way, FWIW, I have a '75 400F and am pretty familiar with them. Used to race against them long ago, and I can tell you that in the right hands they work very well indeed stock!


You will have to excuse me now, I have to go change the spark plug in my lawn mower.

 

[neevo]

Good point and I will park the dramatic changes until I have some time to ride the bike. Short term will focus on good trail numbers and will keep bracing and fuel cells as my backup plan.

 

[doc_rot]

All excellent points made by JP. I only bring up the bracing again because to go back and do it is much more difficult after the frame its painted and the motor in it. I agree that the bracing and fuel cell on that bike, while super fuckin cool, is a huge undertaking and I don't think I would do it myself in your position. However, what if you cut a slot out of a slightly bigger tube and slid it over the existing back bone and welded it in? Im not sure how much clearance you have with the tank though. Perhaps you could split a tube and weld it around the down tube? Thats how the Z1R came from the factory 8) a little gusseting here and there? . Even just a slightly bigger diameter tube will probably help and wont add a ton of weight. just tossing some ideas out here...

 

[jag767]

I am a little out of my depth in this conversation, but hopefully my woeful ignorance can be granted leniency. That being said. I'm not certain exactly all the changes you make to the geometry from stock, but my personal experience on my 350f is with the front end lowered1 to 1.5 inches or so, I know my steering geometry had been altered closer to yours that stock,(in terms of rake) and I have not experienced any adverse effects while riding. Actually I find the steering to be excellent, and at high speed fine just the same. Based on what I gather here, I have increased stress on specific portions of the frame, but I put a fair amount of miles on it and thus far without incident. Now for all I know I built a ticking time bomb, but I I figured it was worth mentioning a little bit of real world application of a similar frame. If I am off base here kindly disregard.

 

[crazypj]

Ed, pretty sure I mentioned at the beginning that you only need to change bearing shells that are damaged? As for bracing frame, unless your going circuit racing, you don't need to do anything much around steering head. You already fixed the major issue by fitting mono-shock.
Personally I would be much more interested in seeing how bad the rear frame flexes with twin shocks and small diameter swing arm pivot

 

[hillsy]

The more good things you add to this bike makes the seat unit shape less suitable IMO.


That's more of a compliment for all the good things you're adding rather than a negative on the seat by the way

 

[neevo]

Ed, pretty sure I mentioned at the beginning that you only need to change bearing shells that are damaged?

All the crank bearings have pits however the big end bearings aren't too bad. Just some minor scuffing.

How would you proceed with that in mind?

Crank bearing condition:





Big ends:







Just not sure how bad bad is and I would prefer to err on the side of caution vs not replacing.

Anything I can save is always a help though.

 

[neevo]

The more good things you add to this bike makes the seat unit shape less suitable IMO.


That's more of a compliment for all the good things you're adding rather than a negative on the seat by the way

Not a problem hillsy, appreciate all the inputs. I'm still sold on the seat at the moment but will keep an eye on it and if I think for a second it won't work, I'll look to make an alternative.

One thing that has been bugging me though had been the stance. I wasn't sure why but the aggressive look I had a while ago had gone. I suspected it might have been the swingarm angle, until I was staring at the bike and had an idea. Maybe it was the tank angle.

I grabbed a tub of Vaseline (it was for packing the oil pump, honestly) and set about making some adjustments.

Before:



After:



Still a fraction too small but the look is much better. I suspect the reason the bike looked funny was because the tank angle didn't match the seat and made it look like the bike was bent in the middle.

I'm liking it, plus it has the advantage of creating a bit more space under the tank for my cool clearance issue.

Just need to make a raised tank rubber mount.

 

[crazypj]

I would only change the bearing shells with the radial scratches.
They are more than likely still OK to use but something got in there and scratched them so could possibly be embedded in bearing material?
As for tank/seat, I prefer the first picture, second looks like tank is 'nose down'
The 'round' seat doesn't really go so well with the 'square' tank in my opinion though but it's pretty difficult to find a 'square' seat that looks good.
Bit of a quandary for you :-\

 

[MotorbikeBruno]

I would only change the bearing shells with the radial scratches.
They are more than likely still OK to use but something got in there and scratched them so could possibly be embedded in bearing material?
As for tank/seat, I prefer the first picture, second looks like tank is 'nose down'
The 'round' seat doesn't really go so well with the 'square' tank in my opinion though but it's pretty difficult to find a 'square' seat that looks good.
Bit of a quandary for you :-\

Yeah, seat bumps are really in the eye of the beholder on bikes (well..most of them...) Maybe you can add a slight matching indent in the rear of it to look like the tank. Or. Ef everyone and keep what you like 8)

 

[neevo]

PJ: I think I will replace all the bearings. There are enough marks on all of them to warrant a change and to be honest I'm not good enough to know which ones I could keep. Given this is a no compromise build I would prefer to know it's all taken care of and I will get years of trouble free riding.

On the seat I might have a crack at a ducktail. I love the look of them but not sure if it's right for this build. But this is my dream bike build here and I can have a go at making the seat, wether I use it or not:

 

[neevo]

Yeah, seat bumps are really in the eye of the beholder on bikes (well..most of them...) Maybe you can add a slight matching indent in the rear of it to look like the tank. Or. Ef everyone and keep what you like 8)

Not wrong Bruno. I'm happy to be challenged on aesthetic elements though as sometimes I get a bit caught up in what I think looks best vs what actually is best.

Will always default to my opinion on aesthetics though as I'm the one that had to look at the thing.

Mechanical hopefully is a different thing though, that's where I will bow to the expert voices on here.

 

[MotorbikeBruno]

Not wrong Bruno. I'm happy to be challenged on aesthetic elements though as sometimes I get a bit caught up in what I think looks best vs what actually is best.

Will always default to my opinion on aesthetics though as I'm the one that had to look at the thing.

Mechanical hopefully is a different thing though, that's where I will bow to the expert voices on here.

I'm with you sir I'm always humbled by how much you can learn from the people on here. It's quite enjoyable. Carry on!

 

[papercutout]

Wow, so after about a month of reading this when I feel like it (my forum input has gone to zero since I opened this thread), I've finished the 170 pages! Definitely subscribing.

So it's been bugging me for aaaaaaaaages that the tank and seat angle didn't match. IMO it's slightly off in the last photo you posted with the vaseline under it, but definitely better!

And I'm so glad you gave up with the modern, large, carbon exhaust idea. It just didn't work for me. Honestly, I think my favourite look is with the carboard tubes you have - plain and simple, no cone-like in or out, just simple tube. Sort of cherry bomb meets Supertrapp meets a nice fancy tigged thing with a ridiculous number of pie cuts.

I'd also try to make an extension for your rear hugger to cover the section under the swingarm brace - less cleaning to do in bad weather. Nice continuity too.
Sorry to say it, and after 2 iterations, I still don't like your tail piece! Still too rounded/bulbous - reminds me of a wasp abdomen, without the streamlined bits. I quite like the one you posted with the 'I want my seat like this' design. I understand you'd have to redo all the items under the tray to make them fit though. Basically, I'd want the height of the bulge to be about 40mm less. You bought a battery that can be laid down, right? (I'm not saying do it, I'm just asking for the sake of asking.

Thanks for the uber read, you've done some amazing work, and have a great workshop/tool collection now! You've learnt a lot, and I've learnt more than I cared to about Honda 400F's... Keep up the brilliant work. (another pommy, but I'm in the UK)