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Soooooooooooo I've been doing some spreadsheet planning. Trying to work out what I've got left to do and how much its going to destroy my wallet. Turns out quite a lot!!!!!
Total build is coming in at about $9k AUD which is a lot for a custom 400F. I've got no issues spending the money as it will be done gradually and it's my hobby too, however I think I'm going a bit overboard by replacing everything on the bike and keen to get some thoughts on areas where I can pull back a bit.
Here are what I consider some optional items I was looking for feedback on. Provide your inputs and it will help me decide.
Acewell Speedo $368.00 eBay (I could go with the cheaper non analogue tacho version)
Rubber Manfolds? $43.40 David Silver Spares (mine aren't too bad)
Dyna-S Ignition $100.00 eBay (could stick to stock points, although cost to renovate could be equal)
466 Oversize Piston Kit (Japan) $140.00 eBay (stick to 400cc saves a fair chunk)
466 Overbore $400.00 (no idea on actual cost)
Cam Chain Sliders $120.00 David Silver Spares (mine are a little worn)
Cam Chain Tensioner $100.00 TTR400 (do I need this performance version)
Big End Bearings $50.00 David Silver Spares (not required but would be good for peace of mind)
Primary Chain $91.00 David Silver Spares (how do I tell if mine is past its best)
Cam Chain $100.00 David Silver Spares (how do I tell if mine is past its best)
HD Studs (APE) $75.00 APE (are these overkill, I have stock ones here)
All this lot totals $1,600 AUD which puts the build into a far more respectable $7k range something I could probably get my money back on. However there is always the peace of mind knowing this stuff is replaced and the bike is essentially brand new.
You can use a CB750 'race' camchain with soft link cheaper than the 'genuine' one.
Just need to shorten it a bit
TTR tensioner? I'll have to look it up but I don't think it's needed
Primary chain?
Probably (I would change it)
If stock studs have zero damage from removal, there is nothing wrong with them for 466 kit (I think I mentioned the highly abused 490 I built?)
If bearings are OK, I don't change them, the oil film is what 'protects' them (and I know you have a good oil pump)
Just looked it up.
Looks pretty but you don't need it.
They seize because chain doesn't get adjusted and chews up the pivot so it can't rotate.
TTR say same thing, won't seize if you adjust chain (and will seize if you don't )
Cheers PJ. I think big end bearings are ok (no scuff marks), so will probably leave them. A few crank bearings have scuffs so I may replace them selectively.
The cam chain tensioner horseshoe is stuffed so hopefully I can get a non damaged one from somewhere. An aftermarket one is always a fallback option.
466 kit is a high priority so may not skimp on that one.
My machine work for the 466 was a little over 200us.. If I remember correctly. I go the new cam chain and tensioner just because. I didn't get the guides because 1. They're ridiculously priced and 2. Mine weren't in bad shape. Plus if you keep your chain properly tightened they shouldn't get used too much. I didn't replace my primary because it didn't have much play in it and my bike only had 14k on it.
As for bearings, my dad told me if you have it taken down that far and you have the money to do it, replace the bearings. It was a little over 200 for all of them (crank and rod) I got new oil seals for everything from David silver spares to, plus a new oil sensor. (too cheap not to get, 5 bucks or something. Got the oem not the genuine) though it's been so long since I have worked on my engine, it's going to be tough figuring out what seal goes where..
+1 all the above could be omitted, but since you're keen on the 466 then you will have to factor in machining. It ought not cost you $400 though - I had my 400 rebored at $60 per pot at peak outrageous Perth boom-town prices. My tensioner was seized, but I carefully filed the burs off and got it moving freely. No issue since. So long as you pay regurlar attention to the camchain tightness then you wont have a recurring problem there.
I think I still have the Cam Chain Tensioner from that motor. It's yours for shipping if it's not damaged. I'll look for it today and take a few pics/make sure the pivot isn't seized.
Changing shell bearings just because you have motor down is an automotive practice and rarely necessary (if they are damaged the crank usually needs a re-grind or replacing)
Oil pumps are nother thing thay car mechanics change 'just because'(usually because they dont have equipment or ability to check specifications)
I've had to dismantle several tensioners on 400's to file off burrs, never had any issues with them if servicing is done
I think I still have the Cam Chain Tensioner from that motor. It's yours for shipping if it's not damaged. I'll look for it today and take a few pics/make sure the pivot isn't seized.
Quick update from my visit to a local performance/head reconditioning shop. Good news, bad news and potentially a silver lining.
Good news: The head is repairable, simple as welding it up and re cutting the valve seats.
Bad news: Probably going to cost between $500 - $600
So here is where the silver lining plays out. Currently I have 2 heads.
Head 1: Buggered cam journal and damaged cam which means the matching rockers are useless
Head 2: Buggered cumbustion chamber and sparkplug thread but good cam and matching valve train.
My idea: Swap the top and bottom of each!
This would leave me with a good top half (with no damage to the cam journal), a good cam with matching rockers and valves. The bottom half would have great condition combustion chambers and sparkplug threads. The only part to be fixed would be the lower half on the cam journal which would probably cost about the same as a new head ($200 - $300).
Are there any issues with my plan?
1. Are there problems putting different valves into the guides?
2. I assume the cams are interchangeable
Question everyone. What is the standard OD of the 400F's headers. My set here is 1.25" into 2" (4-1) but not sure how that compares to stock.
I'm looking to buy some parts from Meg's to build my headers and want to get the dimensions right as its not a straight up build. Keen to aid performance without going to big and causing issues. The build is going to be:
1. Headers into 4-1 collector
2. 4-1 collector into 2-1 collector (reversed)
3. 2-1 collector into 2 outputs
1.5" is way too big, even 1.25" is a bit much but any smaller looks too small.
I think you need closer to 1", that would give you around 7/8" inside diameter.
Even with a 466 kit it's only ~116cc per cylinder.
I would build a step pipe, 1" for first 3"~ 4" out of head, 1.25" for first bend into down pipe, 1.375" about halfway down front to collector then 1.5" from collector to silencer
If you want an expansion box, use 2.50" about 3"~4" long then make a 1:2 stepping down to 1.5 or smaller
You'll have to work out the lengths, they will probably need shortening around 6%~10% from 'theoretical correct'
Question everyone. What is the standard OD of the 400F's headers. My set here is 1.25" into 2" (4-1) but not sure how that compares to stock.
I'm looking to buy some parts from Meg's to build my headers and want to get the dimensions right as its not a straight up build. Keen to aid performance without going to big and causing issues. The build is going to be:
1. Headers into 4-1 collector
2. 4-1 collector into 2-1 collector (reversed)
3. 2-1 collector into 2 outputs
I have one about my 4-1, 1-2, twin mufflers. Is that going to cause issues? I'm sure I've seen it on some bikes.
Reason for doing it is to get the twin mufflers (like a Ducati Monster) primarily but also using the single merge to reduce the need for tuning. Would I be able to count the output from the merge as double of 1 side?
Yes and no. twin pipes of the same combined cross sectional area do not flow as well as a single pipe because of the higher surface area and drag. But at what revs and where exactly is that an issue.
You want 4:1 merge collector with a suitable transition (expands to give that critical flow pattern at the orifice discharge). After that, you could split the pipe into two with slightly larger combined area and push it through two mufflers for twice the muffling volume.
Stock pipes used to be double skinned, so you may be surprised to find how small a stock pipe ID was.
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