The engine rebuild

griff851

Well there you go. I just got back from my first real ride. About 400km. Apart from being knackered, I think anyone consider modifying and engine should think about some things.
1st. Higher compression means higher engine breaking. This became a bit of a hassle and took me some time to get use to how it rides now. Doing the tight winding mountain roads meant hardly any use of the front brake. However it did require some thought on selection of gears. 15/39 is no good, so when I get the 41T rear things should improve.
The engine itself likes to be running around 6-9k now. Making 1st and 2nd gear tight cornering a new art form. Only a couple of rear wheel lock ups going down to first. One just before a wooden bridge. All very entertaining.
As this was just general road yahooing, I only got to select 6th once, and that was only because I hadn't used it so I thought I better. Soon went back to 5th. (never went over 200kmph this trip.)
Second issue. I should have put in a new sprag and starter gear. Mine is fucked now and I'll be dealing with that in a week or so. If i caught on the first start cycle it roars into life no problem, miss that, and trouble and little prayers High comp motors need more oompf to start. Being only 76kg and a new back Tyre, resulted in bump starting being more entertainment. Roll, bump on the seat, one boomph, then slide. Luckily on the third jump on the seat it fired into life. Thankfully I only had to do it once, and as the bike is light, pushing it up to the crest of the hill was relatively easy.
The bonus of the new engine is fucking light speed acceleration. The front wheel just skips across the road lighlty as the bike goes into hyper drive. Man what a rush punching through gears to 9k each time. The bike doesn't power out of corners, it digs a furrow in the tarmac, and leaps out. Man it spins up quick.

The temp did some interesting things. I was getting 80°C and oil at 95°C giving it some going up a windy section, then it would return to 70° water and 75°C oil. At one point while idling (just before the bump start fun) it decided to spew coolant everywhere and the temp was only 78°water 85°C oil. Don't know why it did that, and it didn't do it again.

Griff

Color of the exh pipe is just right, so I think I'll leave the fueling for now.

marvin

Griff,
I too noticed a lot more engine braking with the 12.3/1cr, 907 with the Nichols flywheel. With the strada cams (intakes advanced) it would just squirt out of the corners. I could even pull my friends corse weight 984 until part way down the straights.

griff851

So Marvin what happened to that eng in the end? Did it fail (cases) or transform into something else, or move on (Sold)?

Griff

marvin

griff851 wroteSo Marvin what happened to that eng in the end? Did it fail (cases) or transform into something else, or move on (Sold)? Griff

I sold it to one of our members for his track bike. I decided I wanted to put the Testastretta in the bike. No time, no bike for quite a while now!! Dumb, shoulda ' kept it!

griff851

Good I'm glad to hear it didn't go bang.
Half the time yesterday I was thinking"Mmmm this much grunt = how many hours before destruction." But I get a little paranoid at times.
Griff

brad black

sounds like you need a slipper clutch griff. apart from the push starting anyway.

griff851

Brad, yes that sounds like a solution, apart from the fact that I've been bagging slipper clutches, saying smart arse things like"Why not just lean to change down correctly" and stuff. Mmmm I hate eating words. It will have to wait anyway as i just don't have the cash for one right now. So its technique for a while. Save a fortune in front brake pads.😁

Griff

brad black

yes, i was being helpful, sarcastic and perhaps a little ironic all at once.

griff851

I finally pulled the sprag clutch out last night. Mmmm wasn't real good feel to the whole unit when I first pulled it out. When i put it in, the sprag gripped straight away when you turned the starter gear by hand. No movement. Now when you try to turn it by hand, some times it grips, sometimes it slides then grips. The starter gear bearing surface had false brinelling badly, and the flange now has nice groves in it. New bits time. I did only pay $80 for everything that hangs on the alternator shaft, so I wasn't expecting miracles anyway.
Now here's the good bit. We all know sprag clutches are worth heaps. AUS$290 ish. New starter gear. AUS$350 ish. New flange....... AUS$530 ish. Nuts!
But fear not for me as I have already have 2 of the three components new, on the cheap of coarse, I just didn't want to use them just yet. I'm now tracking down a flange for under $100.
So all be aware that if you have a sound like somebody bashing your cases with a heavy steel ladle during a start cycle. The end is nigh.

Griff

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