Japan Meets Britain

Vince Lupo · Post by **Vince Lupo** » Tue Jun 06, 2017 3:43 pm

I got the springs and retainers in early 2011 from eBay - they came with these race valve springs for a CB77, so I don't know what to tell you. Maybe they did make them at one time but now aren't? Or perhaps they are the same size as another model bike? Either way they've been in my engine for 6 years.

flahotrodder · Post by **flahotrodder** » Thu Jun 08, 2017 1:34 pm

Vince, thanks for the info. I spoke to mega cycle and they have the springs and retainers. I am in the process of building an engine similar to yours except with a 4 speed that has 2nd and 3rd gears x'd. I am using a Harmon Collins cam I have had for years along with early cb750 carbs. Hope your head swap works out. Doug

Vince Lupo · Post by **Vince Lupo** » Tue Jun 13, 2017 1:41 pm

Can't think of a better thing to do (or wear!) in 95+ degree heat.....

Test and Tune Day! The bike is all buttoned back up, and John and I put the bike through its paces today. The bike has a ton of midrange now with the new camshaft and the new ported and polished head, great bottom-end and a bit more at the top. I hit 102mph on my first run (and the speedo is pretty accurate!), though I felt it was 'nosing over' slightly at the top. John changed the main jets from 240 to 250 and then finally settled on 260 mains. Plugs have great colour (for 95 degree heat) and he wants me to ride it some and keep an eye on the plugs. The left pipe does put out a puff of blue smoke every once in a while -- it might possibly need a ring job, but it's not serious to do anything about right now. John had mentioned that those rings never really seated properly (it's a Bore Tech 358 kit), but we're just going to keep an eye on it. Bike runs great.

So far so good, and it's nice to be back on the bike.

SuperHawk 2017 by Vince Lupo, on Flickr

Vince Lupo · Post by **Vince Lupo** » Mon Jun 19, 2017 8:54 am

Went for an early morning ride yesterday, about 100 miles. The bike rides great -- very smooth throughout the entire range, and the midrange is definitely stronger. One issue that I've had for a while and continue to have is that the left cylinder is burning oil. John was never happy about the seating (or lack thereof) of the rings with this Bore Tech kit, and he's thinking of trying the 'Bon Ami' trick to see if that helps.

Fill Er Up by Vince Lupo on Flickr

On an unrelated note, I did a little aesthetic change yesterday. I've had this RAC badge for the longest time, and I thought I'd finally do something with it. I first consulted with our good friend, Graham Curtis (G-Man) to verify the 'period-correctness' of this badge for a bike of this era, plus I looked through a book that I have with period photos of British cafe bikes. I had to make a bracket for it, and it's replaced the 'tax disc' that used the occupy this space under the grab handle. Rule Britannia indeed :)

RAC Badge #1 by Vince Lupo on Flickr

RAC Badge #2 by Vince Lupo on Flickr

Vince Lupo · Post by **Vince Lupo** » Wed Jun 21, 2017 11:10 am

We finally took the plunge and tried the 'Bon Ami' trick this morning (a decent-sized tablespoon through each carb throat). Hopefully it worked-- we didn't smell any more oil coming out of the left exhaust, and we're hopeful that it may have done the trick. Only thing left to do is to clean everything up, fresh oil and filter change, and change the plugs.

Vince Lupo · Post by **Vince Lupo** » Thu Aug 03, 2017 6:19 am

Well we've run into a bit of an issue....

John and I had been doing testing and tuning these past couple of weeks, and we were having a problem with the right cylinder. At WOT the right exhaust was making a 'braaa braaa braaa' sound, and we concluded that it could be the exhaust valve 'floating' because of a weak spring. So he took the head apart and I brought the head back to Mr. Ladd (he did the porting and polishing of the head a few months ago). He had a quick look at it and noticed this on one of the cam lobes:

Camshaft Lobe by Vince Lupo, on Flickr

This is that high-lift camshaft that we just installed a few hundred miles ago. Is this this hard-facing breaking down? Should I now not use this camshaft? I surely don't want to put the bike all back together with a camshaft that might give up the ghost shortly, but I'd rather not send this camshaft to, say, Megacycle to have it refaced (more $$$ of course!). I suppose I could always just go back to the stock camshaft and call it a day. My mechanic John was here earlier today and looked at this photo -- he said it almost looks like it was running without oil, but he knows that's not the case as the top end would always be wet with oil every time he'd take it apart, plus I have the Cappellini 6mm oil pump and oil filter kit, so no problems with oil circulation.

Any suggestions???

G-Man · Post by **G-Man** » Thu Aug 03, 2017 12:32 pm

Vince

What does the mating cam follower look like? Difficult to see from your photo but it does look like it has been hot at some time.

Do you cam followers have the lube hole in the middle of the pad? I don't think those work as well as the early type as the hole breaks up the lubrication 'wedge' across the cam follower.

Id does look like the facing has de-laminated from the base camshaft material. Whether that caused the problem or was a result is difficult to say without closer inspection.

Don't forget that those missing particles are now inside the engine......

I wouldn't re-use that cam if I were you.

More pictures, please.

G