Author Topic: A CB750 race bike build... (Read 14172 times)

Jerry Rxman Griffin aka MuthaF'er · « **Reply #25 on:** February 09, 2018, 08:39:57 PM »

Quote from: Santiago on January 15, 2018, 04:41:20 PM

Quote from: Jerry Rxman Griffin aka MuthaF'er on January 14, 2018, 08:59:07 PM
What are you doing to mate that F3 head to the early jugs as far as the unmatched oil returns go?

No idea! You have any advice? Got told it was possible, but haven't got to that stage yet.

Plug the extra holes.

Santiago · « **Reply #26 on:** February 12, 2018, 12:47:07 AM »

Quote from: Jerry Rxman Griffin aka MuthaF'er on February 09, 2018, 08:39:57 PM

Quote from: Santiago on January 15, 2018, 04:41:20 PM
Quote from: Jerry Rxman Griffin aka MuthaF'er on January 14, 2018, 08:59:07 PM
What are you doing to mate that F3 head to the early jugs as far as the unmatched oil returns go?

No idea! You have any advice? Got told it was possible, but haven't got to that stage yet.

Plug the extra holes.

Thought about it this weekend (was at the Burt Munro Challenge (https://www.facebook.com/BurtMunroChallenge) and discussed it with a mate who races a CB750 and owns about 20 more: what about a Dowty washer under the head nut on the 4 studs that are open to the air?

Santiago · « **Reply #27 on:** July 25, 2018, 01:39:01 AM »

If anyone's still reading my post....been a while since I could get into the shed, I had a job in Europe from March - June, while I was there I managed to get to France to see Daniel Mercier who has the Daytona bike, which wasn't there when I visited (it's in a Museum) but 2 superb replicas in the making were in his workshop. I bought some parts from him including the oil tank, excellent quality and all parts readily available, now that Asa Moyce is retired Daniel seems to be the only one making replica alloy fuel and oil tanks. If you are in France he's worth a visit, he's a great guy and the wine is recommended.

Anyway, I've started on the engine, fitted the Carrillo rods with new bearings to the lightened crank from Cycle X and heavy duty studs to the cases, put 1 piston on a rod and fitted the head (with valves installed but only 1 cam tower and 1 set set of rockers) and barrel with no gaskets, plasticine on the top of the piston, and turned the cam over with a spanner on the thrust end bolt so that I could measure the squish and valve clearance and work out base and head gasket thickness. Got a .005" copper base gasket and .027" copper head gasket ordered from Dynoman, once they arrive assembly can be done.

blacksmith1 · « **Reply #28 on:** July 26, 2018, 02:39:43 AM »

go for it mate,love the cr

SOHC4 Cafe Racer Fan · « **Reply #29 on:** August 07, 2018, 04:54:13 PM »

Quote from: Sam Green Racing on January 14, 2018, 04:23:18 AM

There was a company making them Keith, in Italy I think but production may have stopped now.
They were very expensive.

M3 Racing used to sell them, too. Very pricey hub!

Santiago · « **Reply #30 on:** August 07, 2018, 06:41:07 PM »

Yes, I emailed Mark and asked him if he still had any, but he had none available. I think they can still be arranged through Daniel Mercier, motojlmreplica.com. This one was bought from Disco Volante in the UK many years ago by the gentleman from Japan that I managed to buy it off. It was expensive and needed a trip to Japan to pick it up, luckily I was already there for work, so it came back as luggage.

Santiago · « **Reply #31 on:** February 22, 2019, 12:41:14 AM »

Managed to find a bit of time to get back into the build, so I took the angle grinder to the frame.....

napoleonb · « **Reply #32 on:** February 22, 2019, 09:44:19 AM »

Looking good!

Santiago · « **Reply #33 on:** February 24, 2019, 12:38:51 AM »

I have to paint my bodywork next weekend (only chance to use a spray booth I have access to), so I have to tack the fairing brackets etc to drill everything off. It's all a bit rushed but that's how it goes. I dummy fit the rear wheel, forks, front wheel so that I could get it sitting on the ground and gauge where the fairing bracket needs to be welded on. Fitting the wheels brought home how much work there is to do...lots of little jobs like making spacers for the wheel, to do that I need to fit dummy engine cases with the output shaft and a sprocket on so that I can line the front and rear sprockets up. The fairing in the pic is just sitting propped up by a pair of pliers on the front wheel and the straps holding the bike on the stand....its not the final position, I was just playing around. So don't panic that it is not in the right position

Now I'm getting into the project I'm discovering that the 'project' I inherited (frame, forks etc) was a piece of #$%*, things like the correct engine mount bolts are missing, the swing arm bolt and collars / bushes are junk, the bolts that were attaching the twin discs to the hub were galvanised bolts commonly used for industry and weren't even metric! Better to have started with a complete bike I think....it's going to take a while.

Santiago · « **Reply #34 on:** February 26, 2019, 12:11:24 PM »

Just getting things into position for now. Not easy fitting the fairing.....

bwaller · « **Reply #35 on:** February 26, 2019, 02:13:15 PM »

You might want to wait to play with the fairing until the engine and the pipes are installed. Undoubtedly there will be adjustments afterward!

Santiago · « **Reply #36 on:** February 26, 2019, 02:15:07 PM »

Yep, engines in, got to fit the pipes tonight, nothing's welded on yet, note the speed tape holding the fairing in position at the back.

Sam Green Racing · « **Reply #37 on:** February 27, 2019, 08:43:31 AM »

Coming on well Santiago, I saw your post on FB.

Santiago · « **Reply #38 on:** June 29, 2021, 02:27:44 AM »

Well, work, Covid and other bikes has meant this build stalled for a while. A CB450 needed finishing, but have now done things like making wheel spacers and getting the alignment right, and setting up the foot peg hangers, getting them welded and the exhausts as well. I do small welding jobs but farmed out the exhausts to a pro, they are very thin and my bird#$%* splatter tig welding skills would have blown holes in them 🤣. These are dummy cases just for aligning the wheel sprockets, but my race motor is complete and ready to lift in once the rolling chassis is finished. But I'm away again for work so it will be another 6 months off the bike.....

johno · « **Reply #39 on:** June 29, 2021, 03:54:29 AM »

Hi Santiago,
Your making good progress, for a first time 750 build your doing well. It will start to come together quickly after all the #$%*ty little jobs are done like spacers etc. What are you planning for the ignition ?
You must be the only bloke in the world travelling to lots of countries with all this Covid crap going on. Stay safe.
cheers Johno

Santiago · « **Reply #40 on:** June 29, 2021, 04:07:01 AM »

I've got a crank mounted magneto by Electrex world and I made a semi original style cover out of a DOHC cover cut and welded, circled in this photo. All the holes line up except 1, but I'll get around that by counterboring the electrex world mounting plate, installing a reduced head fastener in the counterbored hole, and using a short bolt threaded into a heli coil in the cover.

I do aircraft lease returns for a job, so need to travel, and covid be damned. But had no work for 7 months in 2020 (I rebuilt a NS250R and did most of the work on the CB450 race bike in that period), then had 6 months in Jakarta, just had 3 months off and now heading up to the UAE for a few months work.

Sam Green Racing · « **Reply #41 on:** June 29, 2021, 01:58:55 PM »

Santiago, jetting about all over the world, it's a wonder you got half of what you did get done, keep up the good work, It'll be worth it in the end.

Sam.

Santiago · « **Reply #42 on:** July 01, 2021, 03:35:12 PM »

Managed to score this off the local auction site, I thought it was a LH hanger and was buying it as a spare, but it's actually a RH hanger, so the hanger for my RH caliper that I'd made from a LH one using spacers etc is now back on the shelf.

johno · « **Reply #43 on:** July 01, 2021, 04:34:40 PM »

Nice pick up, You know the ol saying, Arse beats class.

Santiago · « **Reply #44 on:** July 01, 2021, 05:19:03 PM »

It was certainly very arsey.🤣

scottly · « **Reply #45 on:** July 01, 2021, 07:29:46 PM »

The right side CFC bracket I had did not have the lugs for mounting the fender brace, as it was meant to be used with the stock fender??

Santiago · « **Reply #46 on:** July 01, 2021, 07:44:48 PM »

yeah, this one is symmetrical to the LH side, and appears to be perfect for the race type fender bracket (that I am now making, what a PITA😖)

scottly · « **Reply #47 on:** July 01, 2021, 07:59:09 PM »

That bracket is a unicorn!!

Even the CR "kit" was missing the fender lugs..

Santiago · « **Reply #48 on:** July 01, 2021, 08:09:59 PM »

It’s definitely a Honda part, didn’t come in a bag with a PN but it’s clearly a factory part and not a home made casting. The cognoscenti on this forum will know why it exists I’m sure.

Santiago · « **Reply #49 on:** July 02, 2021, 01:47:27 AM »

I'm trying to do small jobs before I have to go back to work, I drilled out the cemtre of the rear axle, took about 3 hours of very slow machining all the while panicing about not clearing the swarf fast enough, loading up the drill, and seizing it and snapping it off. Saved about 160 grams 🤣. I mounted the unicorn RH hangar (all the bolts are temporary) to mess around with the front mudguard, now I have to turn the cardboard template into a metal one. 😖

News:

Author Topic: A CB750 race bike build... (Read 14172 times)