Topic: CB350f Compatibility

[kolederacer]

Well, my 350f has finally started to smoke somewhat regular and is ready for a rebuild. Of course i want to get more power out of it especially mid and high rpm power and wanted to get some suggestions it already has the normal intake exhaust jet stuff but i plan on at least building the head/cam bore size.
My questions what is compatible with the 350f. Does not have to be direct bolt on machine work is fine. I would rather keep the stock width because i like the narrow look of the bike, but now would be a good time to change it since i am also getting a new exhaust and have been seriously think about the CR carbs.
Thanks for the help in advance.

[kolederacer]

Here is a little photo of the old girl.  I know she is not the prettiest bike out there but always a lot of fun.

[kolederacer]

Also i am fully open to all suggestions engine wise, compression/cam/valve springs or any other things i should know about before going for it.

[Kemp]

I think you can actually bore it to 466cc like the CB400F. I'd check that as its a big performance boost. Mild cam for the street and have Rick Denoon in Winnipeg bore your carbs out 2mm. Get a Yoshima replica exhaust from Moto GP Werks. Gee, I've spent a lot of your money but it will just fly (the bike I mean)!

[kolederacer]

I believe i read somewhere you can have the 400 sleeves pressed into the block and then have them bored to the 466cc also there may be minor things like case boring or moving studs if you swapped to the 400cc head. or i can just keep my head and put larger valves in and have it ported  (if you can find larger valves). The only place i have found for a cam is megacycle is this correct? Also anyone have any parts they want to sell? =D

[kolederacer]

Anyone else try the zxr 400 carbs?

[jamesv220820]

I got you covered I spoke to some great guys over at ttr a while ago and here is what they told me

What can you do to the CB350F Motor?

There are many options; it just depends on how much you want to spend.

Here are a few for you to think about.

Option 1.

Fit new TTR sleeves and bore for STD CB400F 51mm pistons and rings etc.
This also requires the upper crankcase to be opened up larger.
Good port and flow on cyl head and valves (std valves). Fast road camshaft (Webcam or megacycle)
Stock carbs with stock air box. Or pod filters is OK.
A copper head gasket will be required. New pistons, rings and pins are available from David silver spares.

Option 2.

Fit a complete CB400F top end. Upper crankcase will need to be opened up larger.
Bore and fit the Yoshimura 466cc kit (54.5mm) or fit 0.25 OEM CB400F pistons. Rings etc. The 2 front middle cyl studs will need to be changed for custom items. (I can supply these if required)
Good port and flow on cyl head and valves (std valves). Fast road camshaft (Webcam or megacycle). I would also include a set of performance valve springs.
Stock carbs with stock air box. Or pod filters is OK.
You could also have your STD carbs bored larger with the above motor. Rick Denoon in Canada can do this.

Option 3.

As per option 2 but with a full race camshaft and oversize stainless steel valves and bronze guides. But with Keihin 26mm CR Carbs.

OK these are just 3 options for a nice street motor. For a full race motor with no limits more can be done!

For good cyl head work in the USA, I would recommend Mike Riek (on the SOHC forum)

With any of the above options I would also balance the crankshaft, rods and pistons.  I would also fit a new heavy duty cam chain and replace all the cam chain adjuster related parts.

[knowsnothing]

Option 4

Pick up a nice 400f engine and throw it in.  Added bonus - a 6th gear. 

[kolederacer]

I actually found a 400 engine so i am grabbing that. would be better since i can still ride the 350 and build the other.
James thanks for the info. I plan to build it pretty race oriented so not really worried about cruising around town.
The cam/head/valves/valve springs is for sure.
I have the replica yoshi exhaust now.
Going to do the 466 pistons.
Carb wise i dont really want to buy the cr unless i have to.
I read somewhere that someone used zxr 400 carbs and the match up to the ports very well, does anyone have info on this?
Also anything else i need to look at like oiling?

[jamesv220820]

I actually found a 400 engine so i am grabbing that. would be better since i can still ride the 350 and build the other.
James thanks for the info. I plan to build it pretty race oriented so not really worried about cruising around town.
The cam/head/valves/valve springs is for sure.
I have the replica yoshi exhaust now.
Going to do the 466 pistons.
Carb wise i dont really want to buy the cr unless i have to.
I read somewhere that someone used zxr 400 carbs and the match up to the ports very well, does anyone have info on this?
Also anything else i need to look at like oiling?

I am not sure what you are talking about when you say oiling.  If you are referring to the temperature and cooling you can get a fun one from ttr that looks great

[Just4fun]

From what I have read, yosh's early CB400F bikes had oiling problems.  He came up with a way to use 750 oil impeller to improve oil pressure. 

Kevin at TTR, the 400F expert offers a service to do the modification on your core.  I am pulling together parts to do a full build and have one on order (with a bunch of other cool stuff). I figure for the price of all of the performance parts in one of these, the improved oil pump is cheap insurance.

He has the article how to build the pump yourself if you have access to the right equipment.

Kevin also offers larger valves, bronze guides, etc..  oil cooler mounts, almost everything you could want to make a 400F go fast. 

You could not ask for a nicer or more knowledgable guy.  He has been really helpful to me in planning my build.

www.ttr.com


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[calj737]

From what I have read, yosh's early CB400F bikes had oiling problems.  He came up with a way to use 750 oil impeller to improve oil pressure. 

Kevin at TTR, the 400F expert offers a service to do the modification on your core.  I am pulling together parts to do a full build and have one on order (with a bunch of other cool stuff). I figure for the price of all of the performance parts in one of these, the improved oil pump is cheap insurance.

He has the article how to build the pump yourself if you have access to the right equipment.

Kevin also offers larger valves, bronze guides, etc..  oil cooler mounts, almost everything you could want to make a 400F go fast. 

You could not ask for a nicer or more knowledgable guy.  He has been really helpful to me in planning my build.

www.ttr400.com

Corrected link for you. +2 on Kevin. He's among the world's best gentleman, and extremely knowledgeable. I'd trust him with my 8 year old daughter. (not for long, but you get what I mean...;-)

[Robbnc]

I actually found a 400 engine so i am grabbing that. would be better since i can still ride the 350 and build the other.
James thanks for the info. I plan to build it pretty race oriented so not really worried about cruising around town.
The cam/head/valves/valve springs is for sure.
I have the replica yoshi exhaust now.
Going to do the 466 pistons.
Carb wise i dont really want to buy the cr unless i have to.
I read somewhere that someone used zxr 400 carbs and the match up to the ports very well, does anyone have info on this?
Also anything else i need to look at like oiling?

You might want to replace the points with electronic ignition. The stock carbs will do just fine on the 466 once you get it jetted right. That's all that's done to mine and believe me it's plenty fast. Mine is also in a 350f frame. Oh, I did drop a tooth on the front sprocket.

[kolederacer]

Well i picked up a cb400f engine, have the 466cc pistons ordered. Now just need to figure out what to do with the head. probably just cam and cam spring and some porting.