Author Topic: CB 750 Project 1 - Rides Well but a few tweaks needed (Read 116425 times)

timbo750 · « **Reply #375 on:** December 10, 2015, 02:27:04 AM »

I think part of the problem with aluminum is that it stretches. So in theory the long edge of the bent piece is stretched and will never go back to were it was. So when you try to bend it back under different conditions it cracks. And to top it off the cast aluminum is usually not malleable.

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SOHC4 Cafe Racer Fan · « **Reply #376 on:** December 10, 2015, 11:51:55 AM »

Quote from: timbo750 on December 09, 2015, 09:05:31 PM

The other thing I would like to do before assemply is straighten a fin on the head. Its not baddly bent but I am painting the head and cylinders black and would like to sand the fins back and the bent fin is at one of the front corners.
I was thinking of warming the engine in the oven to about 70 to 80 degrees C. They try to manipulte the fin with additionalheat from a heat gun. If the chance of breaking the fin is too high then I wont try, so someone please let me know if I should not try this method.

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I think you'd have to get it WAY hotter to where it is glowing red.

Terry in Australia · « **Reply #377 on:** December 10, 2015, 05:55:04 PM »

I've got a MIG welder with a spool gun set up just for welding alloy, it actually works really well on busted CB750 cases, but when I've welded aluminum, I don't remember seeing it glowing red like steel does? I remember reading up on welding aluminum and they talked about a "straw" color when it's at welding temp, I think if you waited for it to glow red, it might melt? Cheers, Terry. XXX

Terry in Australia · « **Reply #378 on:** December 10, 2015, 06:52:00 PM »

Yep, the "straw" color is just a slight yellow shading, from memory.

timbo750 · « **Reply #379 on:** December 12, 2015, 05:17:31 AM »

Ok then. I am am going to try and straighten the fin by heating it to an almost straw colour and applying gentle pressure to the appropriate area. Wish me luck.

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Terry in Australia · « **Reply #380 on:** December 12, 2015, 03:40:43 PM »

Just don't add too much pressure before the metal is ready to bend back, or it'll snap.

timbo750 · « **Reply #381 on:** December 12, 2015, 04:23:12 PM »

I am thinking of a clamp with a small amount of weight then apply heat . That way I am not going to get too heavy handed on it.

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timbo750 · « **Reply #382 on:** December 12, 2015, 06:58:39 PM »

Whilst doing final prep on the cylinders, I realised that my gasket kit does not have the o'rings that around the base of the sleeves. Can anyone tell me what size they are or should I just place another order with Yamaha?

timbo750 · « **Reply #383 on:** December 12, 2015, 11:22:05 PM »

Found out the size on the Yamiya website and they are not cheap. Over $6 each has made me look for the locally but having trouble. How do I tell if the o'rings I have are still ok or need replacing?

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timbo750 · « **Reply #384 on:** December 13, 2015, 06:55:21 PM »

found the bloody o'rings. In a separate bag that ended up underneath some other stuff, glad I didn't order them.

Terry in Australia · « **Reply #385 on:** December 14, 2015, 12:38:20 AM »

No worries Tim, from memory again, they're not your usual O rings, so I'm glad you found them. I like your idea for bending the fin back, keeping in mind that you'll need to have some sort of "block" to stop if from bending too far past horizontal. Cheers, Terry.

timbo750 · « **Reply #386 on:** December 15, 2015, 06:38:14 PM »

Got the cylinders on yesterday, very happy to see that. Realised afterward that I forgot to fit the cam tensioner and guide, I am hoping that I can raise the cylinders a bit to fit the guide and the tensioner will go on from the top. Fingers crossed.

I am also rethinking the straightening of the fin, the only reason is because of how close it is to the vertical metal rod and that it is most susceptible to splitting.

timbo750 · « **Reply #387 on:** December 16, 2015, 10:20:03 PM »

got the cam guide in, however the rollers for the tensioner that needs the cylinders removed but now I need some cooler weather.

timbo750 · « **Reply #388 on:** December 20, 2015, 02:21:29 PM »

I have now got all the studs to replace the 6mm bolts on the cylinder and head except for the 6mmx102mm. That one is discontinued and I can't find the one suggested by Colin from the KVF400. however I did find a part number from a generator and it turns out there are only 2 left in Japan and then they will also be discontinued. The order is placed today for the last 2, fingers crossed I get them.

timbo750 · « **Reply #389 on:** January 01, 2016, 09:15:16 PM »

I have been working on the reassembly of the guages. I have got tacho together and overall happy except for the crimp ring. I still have the original and try to reuse it on the speedo. I would of got the speedo back together today as well except I didn't notice until I was trying to put it all together that the internal bevel had some slight suface rust. So thats now drying and will be together tomorrow evening.

timbo750 · « **Reply #390 on:** January 04, 2016, 10:03:05 PM »

Finished both guages now and very happy. Managed to manipulate the rubber to hide some of the crimp marks. All I need now is rubber for trip meter.

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Retro Rocket · « **Reply #391 on:** January 04, 2016, 10:33:38 PM »

Looking good Tim....

Terry in Australia · « **Reply #392 on:** January 05, 2016, 01:25:09 AM »

+1 Tim, excellent work.

timbo750 · « **Reply #393 on:** January 05, 2016, 01:33:12 AM »

I am just waiting on the 6mmx102mm stud to arrive and then the engine goes together, gets some paint and then into the frame.

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timbo750 · « **Reply #394 on:** January 05, 2016, 05:03:52 PM »

Just placed an order for a set IKON 7610 shocks, still waiting on the studs, but hope to have engine painted and assembled by the end of the week or weekend or next week knowing my luck.

Stev-o · « **Reply #395 on:** January 05, 2016, 06:20:00 PM »

Quote from: Terry in Australia on January 05, 2016, 01:25:09 AM

+1 Tim, excellent work.

+1 nice job on the gauges

timbo750 · « **Reply #396 on:** January 05, 2016, 07:10:53 PM »

Apart from how frustrating the rings are to close up, the other frustrating things where paying $10.50 for a can of red paint for the tips of the needles and only using the equivalent of 2 drops. And also having to buy a $11 spray can to touch up the internal bezel , the nozzle was pressed for all of 5 seconds and you can bearly see it, however it would of looked half done without it.

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edwardmorris · « **Reply #397 on:** January 05, 2016, 09:57:19 PM »

I had similar trouble with getting the SS ring close properly on the K2 gauges so I stuck with the stock ones for the K3. Surprisingly, the inner bevels on the K2 gauges were spotless, but three other sets I've opened up since have been crap. I found a small vendor online that made mini spray cans of paint that had the perfect color match, plus the can size is tiny, so cheap and not wasteful. Its basically like a supply store for small hobby projects and stuff, can't remember the name.

Terry in Australia · « **Reply #398 on:** January 06, 2016, 12:54:56 AM »

Good choice Tim, I've just installed new Ikon 3612 series shocks on my Harley Sportster, and they're one hell of an improvement over the POS Progressive 412's that were on it! Cheers, Terry.

Stev-o · « **Reply #399 on:** January 06, 2016, 07:08:38 AM »

Hey Guys...I've always been a fan of Koni's and understand the Ikon have evolved from them.

Are the Ikons made in Oz? if so, are you guys getting a good deal on them?

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Author Topic: CB 750 Project 1 - Rides Well but a few tweaks needed (Read 116425 times)