Author Topic: 1975 CB750 K5 "Rhonda the Honda" (Read 92619 times)

70CB750 · « **Reply #25 on:** May 20, 2014, 06:55:06 AM »

I grind piston ring to the right shape for the groove cleaning.

Dremel brush, maybe like this one?

Stev-o · « **Reply #26 on:** May 20, 2014, 06:57:50 AM »

Quote from: 70CB750 on May 20, 2014, 06:55:06 AM

I grind piston ring to the right shape for the groove cleaning.

Dremel brush, maybe like this one?

Piston ring, eh Prokop? Good idea, I've got quite a few of those laying around.

My method has worked, just seems like there could be a better way. Thx

evanphi · « **Reply #27 on:** May 20, 2014, 09:17:02 AM »

Right angle brass wire brush. Put the dremel on a med speed, and run it around the groove for awhile.

These two are also good for cleaning out the rest of the caliper:

Stev-o · « **Reply #28 on:** May 20, 2014, 03:02:43 PM »

Thanks, going to get one...

evanphi · « **Reply #29 on:** July 31, 2014, 08:02:42 AM »

I dropped my bike on the weekend... cracked the underside of the alternator cover. Bled like a stuck pig! Found out here that it is an aftermarket cover, so no major loss...

Quote from: Terry in Australia on July 29, 2014, 02:38:15 AM

Quote from: evanphi on July 28, 2014, 04:39:35 AM
Quote from: Terry in Australia on July 28, 2014, 02:45:42 AM
Quote from: Stev-o on July 27, 2014, 06:34:03 PM
Quote from: evanphi on July 27, 2014, 05:36:08 PM
Thanks for the info, folks.

In sad news, I dropped my bike today. Rhonda took a nap and then started crying oil from the coil cover... nice little crack. So I had to pull all that apart. Going to be a temporary JB Weld fix for the time being, then either a new cover or a quality repair job by a welder in the winter.

If anyone has a generator cover that would fit a K5 going for cheap... pleas PM me.

I wouldn't waste money on repairing it, good time to upgrade to a polished cover.

I hate throwing away good covers because they can be easily welded and polished back to "as new", but that one is a fake anyway, so no biggie. Cheers, Terry.

No "Made in Japan" give it away? A new one from DSS is 250$. Bleh.

Yeah mate, back in the day, as a hard charging 18 year old with a shiney new F0 and no money, I had to replace my alternator cover a couple of times. Those non-genuine (but otherwise identical) covers that were made in Taiwan were available from most bike shops and the price was less than half of the genuine items, so were very popular.

I don't think the quality was less than the originals really, so you could repair it, but of course nowadays the "train spotters" like me would pick it as a fake. Funnily enough, the fakes are probably rarer than the OEM suckers nowadays. Cheers, Terry.

Then I repaired the crack... but my night took a fun turn when reassembling!

Quote from: evanphi on July 31, 2014, 06:56:36 AM

Quote from: MCRider on July 30, 2014, 07:44:52 AM
Quote from: evanphi on July 30, 2014, 06:55:49 AM
Patched my cracked alternator cover with JB weld last night... hammered the dent back outwards as much as we could, roughed up the outside, and dremel'd some grooves over the cracks to have more hold. Cleaned up with degreaser and acetone. Packed the putty in tiiiight.

Sanding up today after work, then hopefully everything back on for a test ride to make sure all is well!
It should work IMO. Degreasing was the most important part. There is no stress or pressure on the cover, oil is flung around but pressure is lost once it exits the crank. It just pools at the bottom and runs back into the crankcases and down to the sump. Good luck!

There would be some heat expansion and contraction, but not so much the JB can't handle it I think.

Hi-Temp JB Weld did a fantastic job! Sanding it down to match countours was no problemo. It is just a different colour now, is all. I also put some Permatex Form 2 around the rubber grommet for the wires coming out of the cover. If the Cash Gods are fair to me this winter, I will likely order an OEM cover.

...but what and adventure I had to endure last night!

I get everything all bolted back together on the inside and I am on my LAST bolt at the bottom (PO put stainless allen bolts on everything, how nice!), and hear the dreaded "tink-tink-tink" and loss of tension that indicates stripped threads... I only was doing hand tight and then 1/4 turn with the ratchet. Luckily for this situation, the bolts the PO put on were a few mm shorter than stock, so I only lost a few threads. I popped down to the hardware store, bought a M6x40mm pan head to hold me over. The distance from the top of the cover's hole to the back of the case hole (threaded all the way through, thankfully!) is 40mm. Before I got that bolt on, the cover was leaking as bad as it was before the hole was fixed! Left it over night and no leaks on the garage floor this morning.

WHEW.

Now to put in an order for some CORRECTLY sized allen bolts... and do something nice for the wife since I spent the whole night in the garage...

"But babe, every minute I'm not trying to fix this problem, money is ~~literally~~ figuratively dripping out of my bike."

I'll take some pictures tonight of the fix. Looks decent, just off colour.

Ravie · « **Reply #30 on:** July 31, 2014, 04:10:21 PM »

I'm not familiar with the "lowering blocks" you speak of. How does that work? (not that i want to do it...just curious)

evanphi · « **Reply #31 on:** July 31, 2014, 05:31:13 PM »

Basically they are a metal piece to move the shock mount on the swingarm back a few inches. It lowers the rear of the bike but severely stiffens the ride.

Ravie · « **Reply #32 on:** July 31, 2014, 06:11:17 PM »

Ah ok.

That exhaust sounds REALLY good.

I've got 2 into 1's that came with my bike that I liked the look of. I'm hoping they sound good. The baffle holes were tiny so I widened them a bit and added one in the center. I took them to the car wash and filled them with presoak and then hit them with high power rinse to get all the old carbon junk out. Then I painted them suckers black with some high temp flat black grill paint. Cheaper than buying a new set up, that's for sure!

evanphi · « **Reply #33 on:** August 01, 2014, 04:52:22 AM »

That is true, black paint just makes everything look good sometimes. I really like the Cone Engineering products, as well as their customer service. I called them up and they told me everything I needed to know. I plan on getting a Bonneville or Scrambler, too... and I will be getting this quiet core again.

evanphi · « **Reply #34 on:** August 01, 2014, 05:06:10 AM »

Pics of the JBWeld repair to the alternator cover. Also the magical panhead bolt that was long enough to get the remaining unstripped threads!

The nice thing about this repair/damage is that you have to be down on its level to see it.

Stev-o · « **Reply #35 on:** August 01, 2014, 05:56:12 AM »

Nice job on the repair.....but I'd consider it a temp fix and replace the cover in the future when possible. I'd hate to be out on a long ride and the repair fail.

evanphi · « **Reply #36 on:** August 01, 2014, 06:13:36 AM »

Thanks

A Dremel and some fine-grit foam sanding blocks go a long way.

I plan to replace the cover this winter, hopefully OEM if the money gods are kind to me. I have a lead on an aftermarket replacement for a nice price, which is what this was.

evanphi · « **Reply #37 on:** August 01, 2014, 09:36:13 AM »

I also finally got around to putting in the solid state Reg/Rec. WOW what a difference.

So far the bike revs higher and pulls harder, according to the ButtDyno, and kick starts WAYYY easier. I haven't changed a single thing, otherwise. Would a bad original reg or rect cause a weak spark, or even poor electrical overall? Awhile back before the swap I was testing voltage to my horn and I was only getting around 11V with the bike not running. Even my headlight seems brighter...

We'll see if this has any effect on my mileage, too. If weak spark and poor detonation was my issue, this may solve it!

evanphi · « **Reply #38 on:** August 12, 2014, 05:33:28 AM »

No improvement to mileage from better reg/rec. My problem is in the carbs, and I'm thinking floats. Next time I have them off I need to:

make sure no gouges in float tang
replace float valves

My float heights are set to spec, 26mm. All the overflow tubes are fine. No cracks. I am always finding, though, that when I turn my fuel back on that I can see it filling up the line to the carbs... which means that fuel is going OUT of the carbs to somewhere. Maybe this is a clue to my problem...

I replaced my chain the other day, too. Much better now! There was a TON of stretch in my old one. Just a cheap one for the rest of the season, and then probably going to do new sprockets and a nice new chain.

evanphi · « **Reply #39 on:** September 09, 2014, 06:29:55 PM »

For more on my mileage plight, see here: http://forums.sohc4.net/index.php?topic=141025

So I bit the bullet and replaced my float valves tonight... All floats set at 26mm.

Old float needle, you can see how worn out it is:

KeiHin (left) vs Keyster replacements (right)

Hopefully the .5mm smaller inlet won't affect performance... The spring in the new needles is much stiffer than the old one. It is 10:30PM now, so I can't start her up to see how things are. But no leaks or anything with carbs back on! I'm getting really good at removing my carbs and getting them back on.

evanphi · « **Reply #40 on:** September 15, 2014, 06:42:25 AM »

Mileage has improved!

Quote from: evanphi on September 12, 2014, 03:03:37 AM

Also... For those interested, my mileage is definitely better. 2.82 gallons (approx... I had already used 1/3 of the 4.7 gal before reserve based on my usual mileage) were used to travel 84.5 miles, resulting in 30MPG. Much better. I was was doing a sweepers run, mostly around 5-6K rpm the whole day, riding rather spiritedly.

I filled the tank on my run, so the true test will be running this current tank down. Based on this calculation, I should get about 225KM before hitting reserve.

Whether it was the new float valves, or setting 2/3 to full advance, that improved the mileage I'll never know... I'm not going to go undoing one of those to find out.

I also changed my air screws to the ones with the holes in them, as per recommendation from HondaMan. Turns out I have K1 carbs (7A stamp) on a K5 engine. They were solid screws before. Solid were at 1-1/8 turns out. Ones with the holes are now at 5/8 turns out. I tried initially at 1 turn, but was WAY too lean.

evanphi · « **Reply #41 on:** October 07, 2014, 05:46:08 PM »

Recent orders:

Weldless frame kit from Frank. (user 754) to help with fixing my recently leaky head gasket. Going to start with a re-torque, and then order a gasket it if that doesn't do it.

Neoprene points gasket from Alex. (user Crush) Because I can. And so should you!

Switched back to solid screws. Holy ones were too lean. Now I'm back to running a touch lean (diagnosed by popping on decel that I didn't have before) because...

I checked my float levels with the clear tube method, and they are lower than before because of the new float needles. I need to measure exactly tomorrow, and set them right (2mm below seal).

Mileage update. I'm a dumbass and was making assumptions about my mileage and not actually looking at my mileage vs. filling of tank. I've started tracking my fuel consumption and have averaged 33.37MPG, riding fairly aggressively, and cruising at 130KM/H when on highway.