Author Topic: CB750 AHRMA Sportsman 750 Racer (Read 175263 times)

slikwilli420 · « **Reply #275 on:** March 23, 2017, 07:04:57 AM »

You running the Dyna S Brent? What size fuse did you use? I figure if it draws up to 8amps, a 10amp will do but wiring is far from my strong suit.

Kickstart · « **Reply #276 on:** March 23, 2017, 07:43:26 AM »

We also just run one main fuse off from the battery... I'm not really picky about the fuse as I figure it's just there to prevent wires melting from a short. I think I've got a 10amp fuse in there right now.

Brent, why the relay? Is that to reduce the current through the on/off/kill switch? I thought about adding a relay but I was worried it would just be one more thing that could break, especially on my CB160 which vibrates a lot more than my 750.

bwaller · « **Reply #277 on:** March 23, 2017, 08:59:24 AM »

Originally used a Dyna 2000 but had numerous problems. I now use a GSXR ignition with Dyna 3ohm coils. The relay is simply so the coils get full voltage and I use a big jeesly 10 or 12ga wire from battery to the relay. Then any switch is just a trigger. Relays are dirt cheap & I've found them to be dead nuts reliable.

Haybus · « **Reply #278 on:** March 23, 2017, 07:18:25 PM »

I too have a single 10A fuse, though I could go smaller, and 12ga wiring throughout. The fuse is simply between the positive side of the battery and the toggle switch. Suggest soldering what connections you can, add service loops where necessary in case you need to remove the loom and re-solder later. My tach has bullet connectors, but it's not part of critical function. I've spent the weekend wondering if wiring was my problem, never again, even though it wasn't.

Alan

Rocketman · « **Reply #279 on:** March 27, 2017, 05:35:00 PM »

Here is the wiring diagram I am using on my total loss system.

My relay is labeled "AR401" and was sold as a 30 amp Driving Light Relay. I mounted it to the rear coil mounting bracket. The wires labeled Trigger and Power go to the positive battery post.

MRieck · « **Reply #280 on:** March 27, 2017, 05:50:48 PM »

Quote from: bwaller on March 23, 2017, 08:59:24 AM

Originally used a Dyna 2000 but had numerous problems. I now use a GSXR ignition with Dyna 3ohm coils. The relay is simply so the coils get full voltage and I use a big jeesly 10 or 12ga wire from battery to the relay. Then any switch is just a trigger. Relays are dirt cheap & I've found them to be dead nuts reliable.

That is a good mod for street bike as well...did it to 2 of my bikes.

slikwilli420 · « **Reply #281 on:** March 28, 2017, 07:26:55 AM »

Thanks for all the feedback guys. I like the idea of a relay to get full voltage where it needs to go. My dad is quite a bit more savvy with this type of stuff than I am so he will be helping me this weekend.

So far I have starting making wiring leads from ignition and coils out of 18awg, but will use some 12 to run from the battery to the fuses and relay, then run the switch and kill button with the smaller gauge stuff. I want to keep this as simple as possible so may be back for some suggestions as I move along.

slikwilli420 · « **Reply #282 on:** March 28, 2017, 07:28:25 AM »

One of the other things I need to tick off the list is a good steering stabilizer. There isnt much out there that I can find that is useful and affordable. You get past $300 quickly with an Ohlins unit, while there are cheaper NHK items, but I am not sure how good they really are.

What are the other racers out there using and how are they mounting so as to not foul the oil cooler?

gschuld · « **Reply #283 on:** March 28, 2017, 10:13:36 AM »

http://forums.sohc4.net/index.php?topic=157550.125
I posted a bunch of pics of how I mounted mine in the 5th (?) Page of the above thread.

The oil cooler type, dimensions, and mount location ideally needs to be coordinated with the damper mount and position. I have taken MANY reference photos of vintage racers at race events and found that the overwhelming majority run the NHK type or something similar.

I am using a modern Ducati 1100 oil cooler on mine. I chose it specifically for both the appearance (it looks very much like a 5 row version of the old CR750 3 row coolers, and the design allows me to BARELY fit the oil lines past the damper mount(top side of the cooler). I mean it's tight. I went out of my way to create a very clean appearance (an unnecessary personal issue).

I had to make custom fittings for the an10 lines to work out the way I wanted it. I don't recommend my specific path, unless you enjoy the punishment.

I wanted the damper setup to allow FULL travel side to side if desired, not something you need for road racing only. But it would be best if you have positive stops on the steering head that bottom out before the damper reaches the end of its stroke on either end. It's a bit of geometry gymnastics, again check my photos for an example. Mockups with cardboard and zip ties, checking clearances with the trees swinging both ways. I chose the left hand side for the damper for no other reason that it will be more natural for me to keep my right hand on the throttle while adjusting the damper with my left hand on the fly if desired. Otherwise, it doesn't seen to matter.

FWIW, NONE of my stuff is tested, never mind battle tested, so take that off what is worth. Theory only

I'm sure others will chime in shortly.

George

Tintop · « **Reply #284 on:** March 28, 2017, 02:37:41 PM »

I used an NHK on my sidecar (mounted left side, same reason as George

). Still going strong 4 seasons later. NHK lists the body size and length of stroke so you can size the damper stoke for full lock. You can find nice billet 35mm fork leg claps, just Google.

Haybus · « **Reply #285 on:** March 28, 2017, 06:54:37 PM »

I have the same NHK ODM500, and it's mounted in the same location as the picture George provided, though my frame side mount is clamp-on aluminum. The clamp allowed me a bit of breathing room when I added the cooler later. Easy to accommodate both when mounting them at the same time.

Alan

Kickstart · « **Reply #286 on:** March 28, 2017, 07:17:30 PM »

I'm using the NHK ODM2000 damper and a fork tube clamp from FastFromThePast.com to mount it to the fork tube... and we made our own smaller tube clamp to mount the other side to the frame.

I'll see if I can dig up a picture.

Rocketman · « **Reply #287 on:** March 28, 2017, 07:22:03 PM »

Have a Shindy Round on my 550. Using the long version.

http://www.shindypro.com/ss.html

Can be found for around $130 on the net. Seems to strike a good balance between performance and price.

bwaller · « **Reply #288 on:** March 29, 2017, 04:34:21 AM »

Usually steering travel needs to be reduced if clip-ons are used so get that sorted before working on a damper mount. (cooler too) I use the NHK on all my bikes, they're good inexpensive dampers but don't last a lifetime. Others like Martin's Shindy which are rebuildable look good too.

I have had one on my CB750 since 1974 and have never adjusted on the fly.

. Just to say (and not to offend those that do) mount it where it fits best and don't make the focus on being able to reach the adjuster knob. On the track I run it at 3 clicks (of 7) and when loading or moving in the shop back it off, because I need an acre to turn the thing around.

You are a good fabricator, mounting in front of the forks, or even over the front of the tank are other options.

slikwilli420 · « **Reply #289 on:** March 29, 2017, 05:49:30 AM »

Thanks for all the thoughts on different styles. I guess I didnt realize the NHK were that ubiquitous in the sport, but they appear to have great reviews. The shindy isnt a whole lot more scratch than the ODM2000 and is rebuildable, which is a nice feature. I also like being able to move the body clamp around a bit on some of the more expensive models, making adjustments easier.

I thought about an arrangement where it attaches to the fork in front and to the steering neck between the forks, that way it doenst fowl my oil cooler, which is taking up most of the real estate in that area, making frame downtube mounting much tougher. If I can mount it low, near the top of the bottom triple clamp, I will still have room for the number plate up front and an area for my tach to be mounted.

Its funny how a race bike is so stripped down, yet you still struggle finding a home for all the bits you need to bolt on!

Tintop · « **Reply #290 on:** March 29, 2017, 02:32:45 PM »

You may want to take a look at how bwaller did his (crosswise in front of the forks). Not sure were the photos are in his build thread though. Would solve your 'real estate' issue, and would sit behind the number plate.

slikwilli420 · « **Reply #291 on:** March 31, 2017, 04:27:20 PM »

Alright on to a new fight. The kill switch.

I bought one that is apparently for a dirt bike that is normally open operation so it grounds out rather than just interrupting power like a normally closed switch would.

Is there a way to properly wire the one I have or should I continue to search for something else? Normally closed kill switches are proving difficult to find that are not tether kill switches.

Thoughts?

754 · « **Reply #292 on:** March 31, 2017, 05:12:29 PM »

Whats wrong with the tether ? Mandatory in a lot of racing.

slikwilli420 · « **Reply #293 on:** March 31, 2017, 05:21:53 PM »

Just another thing to deal with and not required in AHRMA. Just looking for a simple button.

Haybus · « **Reply #294 on:** March 31, 2017, 05:47:48 PM »

You might have a tough time finding a normally closed button to act as a kill switch for a motor sport application. Pingle makes a very nice tether that would do the trick, as Frank suggests. Otherwise maybe a simple toggle? That's what I use.

Alan

scottly · « **Reply #295 on:** March 31, 2017, 06:03:59 PM »

The other problem with a momentary kill switch is that as soon as the button is released, the ignition is energized again; you would also have to have a main shutoff switch to prevent draining the battery. I use a mini toggle switch, mounted on the right side of the handle bar, where I can flick it off or on with my thumb. If you are going to use a relay, wire the switch to the ground side of the relay coil, and the positive side of the coil to the fuse. This way, with one switch terminal grounded at the handle bars, you only have to run one small wire from the switch to the relay.

slikwilli420 · « **Reply #296 on:** March 31, 2017, 06:13:59 PM »

The whole relay thing doesn't jive in my head. Since there are no high draw items on the bike, what's the point/purpose?

I also have a main switch for power that will be located elsewhere.

scottly · « **Reply #297 on:** March 31, 2017, 06:31:06 PM »

The mini toggle switches won't carry the current your ignition system will draw, if the info Dyna gave you is true. With the relay, you could have one toggle switch for turning the bike off and on where it is easily accessible.

slikwilli420 · « **Reply #298 on:** March 31, 2017, 06:34:39 PM »

Could you draw something up please? I have the one from rocketman but it didn't really make sense. I need to have the whole thing so I know what goes where.

scottly · « **Reply #299 on:** March 31, 2017, 07:06:52 PM »

I never claimed to be an artist, but this may give you an idea what I'm talking about:

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Author Topic: CB750 AHRMA Sportsman 750 Racer (Read 175263 times)