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Messages - fisjon
16
« on: February 26, 2014, 08:47:43 PM »
I would change the bearings as a matter of course, if one is on it's way, disturbing it during a rebuild is the quickest way of pushing it 'over the edge' and you just don't want to do another strip down and rebuild to replace a whining bearing.
They can be expensive if you buy Honda originals, but each bearing has a number on it.
Take that number (and the bearing) to a good bearing supplier and tell him it is for a high revving Honda and he should be able to match the bearing exactly, at a fraction of the cost.
All bar one of the bearings that went into my cb650Z were made in Taiwan. Taiwan supplies Japan with bearings for the major bike manufacturers. You can get the same bearing in a different box for half the price!
17
« on: February 24, 2014, 05:35:10 PM »
What is PQR15? is that the same as POR15. Norniron, you have some paint to do your frame now 
Aha! should have gone to Specsavers, I had to go and check the tin to make sure and it is indeed POR 15 
18
« on: February 22, 2014, 07:44:04 PM »
I used PQR on a tank for my cb650Z. I was meticulous with the prep and waited several weeks before filling with fuel. It lasted three weeks before is started to leak again. Not impressed!
In the end I spotted a new tank in David Silver and two side panels in Germany. I stomped on the old tank and bought the NOS ones. Cost £430. But when you deduct the cost of the PQR 15, the cost of the paint and add in the time to do it all without any guarantee that it will work or look good, it isn't so expensive.
It looked fab.
I learned the hard way and would go for a new tank ready painted up anytime.
19
« on: February 21, 2014, 04:16:28 PM »
This engine really was labour of love!
My buddy said, (after seeing my CB650Z) any chance of helping me with my 400/4 resto.
Ok I said and the engine was dumped in my garage complete with packed cow shit underneath (god knows where he had been).
A fortnight to clean all the crap off then a complete strip. It had a knackered cam belt adjuster and a 550 cam belt slider stuffed inside. No wonder the adjuster was shot. It cost £580 to rebuild.
Once the cases were stripped I just shoved it my bead blaster and gave it some stick. I then gave it some time with the high pressure washer making sure all the glass bead was out (you have to be meticulous) and dried it out. I painted the casings with a cheap engine paint as my mate was a bit of a scrooge but it came up really well. It's all down to preparation, if it is clean and smooth the paint will take well.
20
« on: February 19, 2014, 05:09:23 PM »
When your done it should look like this 
21
« on: February 16, 2014, 07:29:26 PM »
Yes, my CB650Z rear spindle fitted straight into the rotor and I used an old hub to slide along the shaft to whip it out. I remember this well as when the old hub got to the end of the shaft my finger was still there! F**k!
22
« on: January 15, 2014, 07:29:36 PM »
I had a CB750K1 back in 1972, they did snap chains from time to time and I had one shoot past my leg and wrap itself around the frame. Some did smash the cases up so there will be some around that were replaced.
My engine was one of the ones with the faulty gear selector barrel and it shot out of gear at about 95mph on the M4. The needle on the rev counter went off the scale and it caused internal damage. Honda striped it once as it had only done 900 miles but I wasn't happy with it so I stripped it myself a couple on months later to find they had not changed the cam chain and it was knackered.
The thing is I don't remember there being three springs on the valves, just an inner and an outer. In fact I haven't come across that on any of the Honda fours.
By the way, (in case you are not aware) the inner springs are graded (one end is more tightly wound than the other) the tightly wound end should be fitted nearest to the cylinder head. A lot of the engines I have worked on have the springs just put in willy nilly.
23
« on: January 10, 2014, 08:26:24 PM »
The 8mm bolts are 24-30N.m / 17-22 ft-lb
The 6mm bolts are 10-14N.m / 7-10 ft-lb
tighten the bolts in 2-3 steps in the following number sequence:
with exhaust facing you numbers are from left to right inlet side
12 8 4 2 6 10
with exhaust facing you numbers are from left to right exhaust side
11 7 1 3 5 9
Just start at no 1 and follow through.........................
24
« on: December 18, 2013, 07:01:09 PM »
Humm! no picture, trying to work out why..............!!
Ok put a link in the above message to view photo of motor...sorted
25
« on: December 18, 2013, 06:49:56 PM »
Click the link below to see a photo of a CB650Z motor with Blue hylomar on the joints that I built up two years ago. I put it on with a plastic shringe, placing a tiny bead on the outer edges of the casing, but as you see even a thin bead is probably too much. I looked inside the engine with a torch and could see a few small blobs and removed them, problem is you cant see inside the gearbox once it is sealed so it was crossed fingers after that. As far as I know the motor is still purring. I think the cases are so well machined that just an even smudge will be enough to form a seal. http://www.sohc.co.uk/index.php?topic=4964.msg25045#msg25045
26
« on: December 17, 2013, 08:04:39 PM »
My CB750K1 came on the cam at 5300 revs, exactly at 70mph.
Quite revy in contrast with my GT750K which purred at 90mph at only 4000 revs, mind you it did come with a 'chips' highway patrol front sprocket, (one extra tooth).
27
« on: December 02, 2013, 06:19:44 PM »
I would agree with Steff750, back in the 70's big bore kits were all the rage and there were many questions about upsizing the jets.
The thing is, if you alter the exhaust, you generally need to alter the jets to compensate for the loss of back pressure. When my 750K1 exhausts rotted and fell off I fitted Dunstall four into twos, and the correct jets came with the kit. The bugger then gobbled fuel, ran ok but really did not go any quicker as Dunstall would have you believe.
If you are increasing capacity, but are not increasing the choke diameter, then there is little to gain by changing the jets. The bigger pistons will suck more air per stroke, but the carbs will simply supply the correct fuel/air mixture according to demand, that's what carbs do. It does not matter whether x amount of air is being demanded by a 736 or 836 motor providing that the choke size can cope with demand, which it can. If you were to go track racing, and wanted peak power then you would mod the intake and put larger carbs on.
If it worries you, check the plug colour after some use, if you feel that the motor is running a tad weak you can always lift the needle jet one notch but I think you won't need to alter the carbs at all for normal use.
28
« on: November 27, 2013, 08:15:02 PM »
My mate wanted to try putting some easy start down the carbs. It blow a flame out the exhaust but no bang just a woosh sound. Timing?
YIKES! I would pull it apart and rebuild yourself or you might end up with a pile of nuts and bolts on the drive............. 
29
« on: November 25, 2013, 09:21:01 PM »
I could be a dislodged or broken cam chain slipper or even a broken cam chain adjuster. If that has happened then the chain could jump a cog on the crank and if that happens when the engine is running then you have a disaster.
I would whip the head off and have a good look.
30
« on: November 24, 2013, 08:00:01 PM »
I wonder if ultrasonic cleaning might just dislodge one of the blanking plugs/pellets ?
Found that the Keyster valves were worse so took the advice of others and used sime metal polish to "gently" clean up to float needle and valve seat.... No piddling carbs since.
Yes, ultrasonic cleaning can and does pop out the odd blanking plug. They are easily refitted with epoxy resin. After popping carbs in my unit I alway check to see what is lurking in the bottom of the tank.
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