Author Topic: Classic Bonneville Racer  (Read 116341 times)

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Offline Old Scrambler

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Re: Classic Bonneville Racer
« Reply #675 on: September 11, 2021, 06:00:01 PM »
Found the leak............a very small hole in the weld at the bottom rear of one of my tanks. It was newly welded in Pocatello because I had both tanks shortened to get clearance for my hands on the grips. The leak was more of a smear and must have allowed salt to enter the tank when making runs due to air-pressure........I can see flow-marks on the bottom of the tank. Soooooo........maybe I need to find a better welder ;) ;)
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
CB750 Classic Bonneville Racer thread - http://forums.sohc4.net/index.php/topic,135473.0.html
'63 CL72 Project(s)
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Offline 754

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Re: Classic Bonneville Racer
« Reply #676 on: September 12, 2021, 10:40:13 AM »
 Bonneville, tough place to go fast..
 And easy to have problems or glitches..sometimes....... in places you didnt know you had places..
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Offline dragracer

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Re: Classic Bonneville Racer
« Reply #677 on: September 13, 2021, 10:15:30 PM »
Glad you're figuring a lot out now Dennis. Watching the 2023 flats runs in person should prove to be an interesting event for me. 

Offline scottly

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Re: Classic Bonneville Racer
« Reply #678 on: October 21, 2021, 07:38:03 PM »
Dennis, regarding your PM, yes, if you want to bring the CBR to my shop, I will be happy to put it on the dyno and help find those ponies you were missing, free of charge. ;D ;D
Don't fix it if it ain't broke!
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Offline Old Scrambler

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Re: Classic Bonneville Racer
« Reply #679 on: October 22, 2021, 10:17:14 AM »
OK...........will have more to discuss later.........If all goes well, we should be travelling the weekend before Thanksgiving.

Bare bike with carbs off. I'll try to bring what's needed. This venture should be FUN ;D
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
CB750 Classic Bonneville Racer thread - http://forums.sohc4.net/index.php/topic,135473.0.html
'63 CL72 Project(s)
'66 CL77 Red
'67 Triumph T100C
'73 750K3 Owned since New
'77 750F2 Cafe Project
2020 ROYAL ENFIELD Himalayan

Offline scottly

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Re: Classic Bonneville Racer
« Reply #680 on: November 14, 2021, 07:52:00 PM »
Are you still planning on heading this way soon? Also, does your bike have an on-board starter, or do you use a roller starter?
Don't fix it if it ain't broke!
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Offline Old Scrambler

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Re: Classic Bonneville Racer
« Reply #681 on: November 15, 2021, 05:21:23 PM »
I can put weight on my ankle, but will be in PE up to 6-weeks. Will see the Doc in late December for final checkup. So don't get anxious. New ETA is early January. Will likely travel via Las Vegas to avoid snow in Utah.

Yes, onboard starter. will have batteries with me. Our daughter and son-in-law's land is more than an hour from you on a good day.
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
CB750 Classic Bonneville Racer thread - http://forums.sohc4.net/index.php/topic,135473.0.html
'63 CL72 Project(s)
'66 CL77 Red
'67 Triumph T100C
'73 750K3 Owned since New
'77 750F2 Cafe Project
2020 ROYAL ENFIELD Himalayan

Offline scottly

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Re: Classic Bonneville Racer
« Reply #682 on: February 09, 2022, 07:26:50 PM »
How's your foot doing Dennis? :)
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline Old Scrambler

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Re: Classic Bonneville Racer
« Reply #683 on: February 10, 2022, 12:54:07 PM »
'graduated' from PT................Pushed a bike today and climbed a ladder ;D

Getting 2nd Covid booster next Monday..............then to Pheonix to unload the trailer and settle Carol at her cousin's home. I should be seeing you in 10-12 days, the 21st or soon after.
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
CB750 Classic Bonneville Racer thread - http://forums.sohc4.net/index.php/topic,135473.0.html
'63 CL72 Project(s)
'66 CL77 Red
'67 Triumph T100C
'73 750K3 Owned since New
'77 750F2 Cafe Project
2020 ROYAL ENFIELD Himalayan

Offline scottly

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Re: Classic Bonneville Racer
« Reply #684 on: February 28, 2022, 07:13:07 PM »
This is the side of the shop you will see as you come down Prescott st. The door is where the bike goes into the shop and on the dyno, so it may be best to unload the bike there, before parking the rig behind the shop.
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Classic Bonneville Racer
« Reply #685 on: March 01, 2022, 08:28:46 AM »
Getr tuned boys
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline scottly

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Re: Classic Bonneville Racer
« Reply #686 on: March 01, 2022, 06:12:54 PM »
Dennis got here around 11:00, we get the bike strapped down on the dyno, the cooling and exhaust fans set up, and the computer booted up, and for some reason the dyno won't communicate with the computer!!!??? The dyno status indicator on the panel is lit up properly, but the computer can't see the output from the dyno on the serial port; it's like the cable is unplugged from the computer. The program boots up correctly, but shows the dyno is not connected. Nothing I tried worked. >:( >:( >:(
We finally gave up and took the bike off the dyno and put it back in the trailer; Dennis left here about 6:00... :(
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline johno

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Re: Classic Bonneville Racer
« Reply #687 on: March 01, 2022, 10:08:23 PM »
I thought that #$%*e only happened to me ;D
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Offline Old Scrambler

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Re: Classic Bonneville Racer
« Reply #688 on: March 02, 2022, 09:58:34 AM »
Meanwhile...............I am back in Tempe, part of Phoenix. Will attempt to get my daughter's DR650 running and will temporarily park the C.B.R. inI Cousin's garage for a 4-5 week RV and RZR tour of the Apache-Nation's historical hiding places in SE Arizona and Western New Mexico. Then return to pick up the C.B.R. and give it another try with Scott before heading to Pocatello for some Dr. appointments in late April. I have the Himalayan in the trailer, so somewhere in our travels I will begin riding it when my ankle is at full strength.
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
CB750 Classic Bonneville Racer thread - http://forums.sohc4.net/index.php/topic,135473.0.html
'63 CL72 Project(s)
'66 CL77 Red
'67 Triumph T100C
'73 750K3 Owned since New
'77 750F2 Cafe Project
2020 ROYAL ENFIELD Himalayan

Offline scottly

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Re: Classic Bonneville Racer
« Reply #689 on: March 02, 2022, 08:26:47 PM »
Hey Johno, your name came up early in the visit, and I suddenly remembered your xmas gift from what, 8 years ago? The stainless engine mounts, while being very nice pieces, wouldn't work on my Seeley frame, and it occurred to me they should be passed on to Dennis, so his visit wasn't a total loss. ;D ;D
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline johno

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Re: Classic Bonneville Racer
« Reply #690 on: March 04, 2022, 02:41:34 PM »
Good call Scottly, that's typical SOHC forum smarts. 
It also means both of us are starting to get a bit older mate. ;D
GRASSHOPPER SOHC HONDAS ARE THE MEANING OF LIFE.

Offline bear

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Re: Classic Bonneville Racer
« Reply #691 on: March 04, 2022, 08:03:23 PM »
Good call Scottly, that's typical SOHC forum smarts. 
It also means both of us are starting to get a bit older mate. ;D


Older is just a given. But with you two the "smarts" bit is mildly surprising. ;D ;D ;D ;D
The older I get the faster I was.

Offline scottly

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Re: Classic Bonneville Racer
« Reply #692 on: March 04, 2022, 08:56:33 PM »
[

Older is just a given. But with you two the "smarts" bit is mildly surprising. ;D ;D ;D ;D
Ouch!!! ;D
Don't fix it if it ain't broke!
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Offline scottly

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Re: Classic Bonneville Racer
« Reply #693 on: April 02, 2022, 07:35:08 PM »
I got the dyno fixed today!! ;D ;D ;D The culprit was a bad Cmos battery in the bottom of the CPU module of the dyno electronics "stack". I found a thread on a Harley forum that talked about the battery, and despite claims that the Cmos would be erased, a recent post reported that changing the battery fixed his dyno. The replacement battery was only $14, but it took a lot of work to get to it. ;) Now I just have to put the whole thing back together..
 
« Last Edit: April 02, 2022, 07:38:02 PM by scottly »
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Offline gschuld

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Re: Classic Bonneville Racer
« Reply #694 on: April 03, 2022, 05:49:42 AM »
Great news!   No fun having a broken toy….

George

Offline scottly

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Re: Classic Bonneville Racer
« Reply #695 on: April 03, 2022, 09:59:18 PM »
George, you have no idea how relieved I was when the battery fixed the dyno!!! If it hadn't worked, I would have to have resorted to Dyno Jet's technical support, which would cost $500 just to "register" my used dyno, before they would even talk to me, much less sell me any replacement parts. >:( Also, from what I've read, they no longer support my hardware/software version, and charge upwards of $5K to upgrade!?? I have not found any mention of the CPU battery on their web site, but there was a link on the Harley forum thread to detailed replacement instructions from Dyno Jet? I'm tempted to call them up and innocently ask what it would take to repair my formerly ailing dyno, just to see what they say. ;) No way I would pay $5K to "upgrade"! I would have explored other options, such as the data acquisition hardware you were thinking of for your project. ;D 
Don't fix it if it ain't broke!
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Offline scottly

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Re: Classic Bonneville Racer
« Reply #696 on: April 07, 2022, 10:14:46 PM »
Dennis made it back up here today, and while the dyno worked properly (disregarding any operator errors ::)), the CBR had a few issues, like fuel leaks. ;D We did get one decent run logged, which shows the AFR was too lean, at more than 14:1 instead of the nominal 13:1 for max power. This was with 120 main jets, and was about 10 HP less than a 2015 dyno test with 125 main jets? At the end of the run, the bike spat oil on the hot exhaust, creating a short burst of smoke as well as spraying oil out onto the floor on the left side of the bike!!?? I think Dennis was correct when he suggested the cooling fan blew the oil to the side. Looking at both the old dyno chart and today's chart, there is no reason to rev this motor any faster than about 10K RPM, as it gets it peak HP at about 9.2K, at least with 125 mains. The oil issue was most likely due to excessive RPM, IMHO ;)
All in all, it was a fun afternoon, and a pleasure to see Dennis again and meet his wife. 8) 8)
« Last Edit: April 07, 2022, 10:21:59 PM by scottly »
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Classic Bonneville Racer
« Reply #697 on: April 08, 2022, 08:43:40 AM »
You guys going to re-jet and run it again?

What elevation?

More rpms mean higher speed if it will pull the necessary gearing for 150mph?
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline bear

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Re: Classic Bonneville Racer
« Reply #698 on: April 08, 2022, 07:58:27 PM »
I don't know one end of a landspeed bike from another but I have learnt it's unwise to stray to far from the top of your curve for any sustainable high performance. As for speed.......that's why God gave us gearing options. ;)
So I'm with you Scott. I suspect that as it had the tits reved off it, it built up crankcase pressure.

I believe the key to good sustainable  HP in these engines is to concentrate on higher cylinder pressure not higher revs. These engines strong point is their ability to handle high loads not high revs

There you go, that's my unsolicited opinion it's time to get back in my box. ;D

« Last Edit: May 12, 2022, 07:18:15 AM by bear »
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Offline scottly

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Re: Classic Bonneville Racer
« Reply #699 on: April 08, 2022, 09:45:48 PM »
Jerry, the elevation here is 4500', close to the same as Bonneville, but that's what the correction factor is for: in this case it was 1.16x the measured hp to read what it would be at sea level. The major factor is the barometric pressure, which was about 25.5"/hg, compared to about 29" at sea level. 2"/hg is around 1 PSI, so you would have to "boost" a motor almost 2 PSI to achieve sea level performance here. When Dennis left here yesterday afternoon, they were heading back to Idaho.
I had remarked to Dennis that I'd seen a rather similar lumpy-bumpy curve before with a lean condition, and found it today. IIRC, I had swapped in a set of 32mm chokes in place of the 30mm the Webers had been tuned for? The first chart shows the previous run with the proper jetting and the next run with the lean jetting; notice the HP difference. The second chart shows my lean jetting superimposed with the CBR; notice the similarities in the bumpiness and AFR above 7000 RPM.
 
« Last Edit: April 08, 2022, 09:48:34 PM by scottly »
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....