Topic: Bolt and Washer on Cyl 1 side of Cam End

[LiveeviL81]

What is the purpose of this thick steel washer and bolt on the end of the Cyl 1 side of the Cam? Looks to be an M8, Was pretty tight, but I can't find a torque reference in the manual or reason for it? I assume it is to be a "thrust washer" for the end of the cam bearings, but it is weird there is only one side tapped. I am doing an EFI conversion on the bike and adding a tab between the thick washer and bolt seems like a good idea for a place for the cam position sensor and pickup.

[69cb750]

It holds the camshaft centered in the bearings.
10# sounds good.

[LiveeviL81]

Not sure how it holds the camshaft center my washer doesn't seem to be touching any of those bearing surfaces, only the side of the lower bearing surface?

[Don R]

  I've always prescribed to the notion if it wasn't there for a reason, Honda wouldn't waste the yen it cost to drill, tap and buy the washer and bolt hundreds of thousands of times.

[HondaMan]

Yep, that's the Locator Washer for the cam: I can attest that when a BrandX cam was installed in a 750K4 engine here in Colorado (circa 2008) without using that washer, the cam could wander back-and-forth enough to chip and groove the cam lobe edges against the rockers. The rockers are harder than the cam lobes. It limits the sideways movement to less than 1mm.

A hint if you're thinking about Megasquirt: one of our members (15 years back?) did that conversion, i think it was on a 750K4. He found the idle had to be close to 1500 RPM because of the single-squirt-per-cam-revolution design (much like in the old Kawi LTD system), so the spark advancer's springs had to be tightened up to delay start-of-advance to 1600 RPM or so (also like the Kawi) or the engine would just start up and run to 3500-ish RPM at idle, then die when hot. That particular Megasquirt had a fuel delivery limitation that limited top speed to 98 MPH (100 MPH on a good, cool day - he lived in Louisiana).

[LiveeviL81]

Thanks Hondaman, exactly the information I was looking for. Plan is to make a tab that sits between the bolt and washer and bends up and make a flat for the hall effect to pickup, that'll be mounted on the valve cover. With the bolt clamped down and tight I should be able to clock the pickup then lock it down. Plan is to do sequential injection with a crank pickup as well, photo's to follow. It is microsquirt based, should help give me some more control on the hondamatic with the turbo. stock spark advancer is deleted and will just be a 24-1 tooth wheel on the crank.

[Don R]

 We would love some pics and to follow along. I've got a turbo bike in the part collecting phase. Not crazy about the Bendix carb that came with it.

[HondaMan]

Thanks Hondaman, exactly the information I was looking for. Plan is to make a tab that sits between the bolt and washer and bends up and make a flat for the hall effect to pickup, that'll be mounted on the valve cover. With the bolt clamped down and tight I should be able to clock the pickup then lock it down. Plan is to do sequential injection with a crank pickup as well, photo's to follow. It is microsquirt based, should help give me some more control on the hondamatic with the turbo. stock spark advancer is deleted and will just be a 24-1 tooth wheel on the crank.

Very cool idea for a 'Matic!
You GOTTA put a build thread for this one.

Please?
 

If I personally had (have?) the chance sometime, I want to build a Megasquirt on a CB500/550 (with all LED lighting, it'll need that to run the 'squirter) because I believe there is 60 streetable HP lurking in the Mid-Four that's just never been coaxed out of it. The main reason is/was the politically-forced carb system(s) it had to have in the 1970s that limited its performance for emissions reasons, at low cost.

I have seen a CB500 dragster before, with much-modified intake tracts and 4-2 open megaphones that could beat stock CB750s in a dragstrip situation. The bike was reputed to have 1st-oversize Honda pistons, aftermarket cam, hand-built exhaust and some form of EFI [from some other unnamed bike]. It was running about 9000-10,000 RPM shifts and left the line like the lightweight it is. I don't remember the ETs offhand, but it was running up against KZ1000s and CB750s and holding its own.

The CB500/550 also has poor intake ports in its OEM configuration, largely for the afore-mentioned emissions reasons of the time when it appeared. With adequate carbs/EFI an augmented intake tract could really liven them up, as it even does with stock carbs.

[LiveeviL81]

Here is a link to my old build log that I wrote a bit in tonight to try to update it to what I am currently working on.

http://forums.sohc4.net/index.php/topic,194154.25.html

Hondaman, I was following along with the Turbo CB550 Landspeed build and have been amazed at the power he has coaxed out of the engine using just a big turbo and draw through. I have kept my eye open for a CB350/4 or 400/4 before to do some sort of build on, but they are getting rare it seems. I wanted to find a build for a CB400/4 that could rev happily to 12-13krpm as some of the early 2000's I4 were my favorite sound engines, but I hate crotch rockets! Whoops distracted...

A Megasquirt CB550 street able bike could be a really good project idea!