B50 MX for Bonneville

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Re: B50 MX for Bonneville

Post by Andy Chaos » Sun Jan 22, 2017 2:24 pm

Each tank has its own tap Tom and connect to the carb with a duel banjo,The steel balance pipe at the rear is for filling both sides and makes both tanks one solid unit for easy removal, they fill equally and drain totally. Also we are not planning on doing as many miles this time. Rick and I are almost related we spent that much time (and money) with him :grin:

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Re: B50 MX for Bonneville

Post by Andy Chaos » Mon Jan 30, 2017 8:00 pm

Well the frame is modified and off to be painted so i decided to have a quick look inside the motor before it goes off for development.
This site is full of experts on all things B50 looking at the colour / color was it rich or lean :???: :werd
The good news is no valve contact and the bore is gorgeous (must be the castrol R) :thumb
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Re: B50 MX for Bonneville

Post by stew79 » Mon Jan 30, 2017 8:34 pm

andy, that just looks odd !
stew

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Re: B50 MX for Bonneville

Post by beat » Mon Jan 30, 2017 8:49 pm

Andy Chaos wrote: was it rich or lean
what a slurry was it burning ??
added Water ??

guess this combustion chamber never was really running hot for best output.

rich ore lean? your A/F - R Meter should tell you that !

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Re: B50 MX for Bonneville

Post by Andy Chaos » Mon Jan 30, 2017 9:20 pm

If you remember the AFR showed massive lean so we went as rich as we could and it went slower, returned to smaller jets and it just got quicker. I have never seen fuel burn like this, i can wipe the the deposit off with my finger. :werd

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Re: B50 MX for Bonneville

Post by HPbyStan » Mon Jan 30, 2017 9:48 pm

Where is the 2ed spark plug so both halves of the combustion chamber produce power ? :roll:
Just teasing mostly.

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Re: B50 MX for Bonneville

Post by koncretekid » Tue Jan 31, 2017 1:59 am

Andy,
My cylinder head after 2013 at Bonneville for comparison. I used the same gas that you did in 2016, about 12.5/1 compression, 92mm piston, 75mm stroke, Boyer ignition, Megacycle X4 cam, 42mm Mikuni flatslide carb. Spark plugs are obviously not fully screwed in.

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Re: B50 MX for Bonneville

Post by HPbyStan » Tue Jan 31, 2017 3:19 am

That sure looks more like it huh.

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Re: B50 MX for Bonneville

Post by hwan » Tue Jan 31, 2017 11:12 am

does look odd, but then again we were getting confused and as Andy says, they went in wrong direction to start with.

Wonder if is a lack of CR - lower cylinder pressure/temperature ??

Andy will get it sorted for the next time.

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Re: B50 MX for Bonneville

Post by beat » Tue Jan 31, 2017 7:06 pm

Tom's head looks good, - And is head looks for water IMO.

:uhu

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Re: B50 MX for Bonneville

Post by minetymenace » Tue Jan 31, 2017 7:27 pm

I think all the water has drained down those little holes in the middle of the valves....never seen them before, what is that all about?
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Re: B50 MX for Bonneville

Post by hwan » Tue Jan 31, 2017 7:37 pm

To lighten the valve (??) and/or provide a center while machining them - i presume the stem was centerless ground ?

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Re: B50 MX for Bonneville

Post by HPbyStan » Wed Feb 01, 2017 4:50 am

Del West 350 Chevrolet titanium valves need to be cut down to B50 dias.

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Re: B50 MX for Bonneville

Post by koncretekid » Wed Feb 01, 2017 12:55 pm

HPbyStan wrote:Del West 350 Chevrolet titanium valves need to be cut down to B50 dias.
Exactly. I bought used Chevrolet NASCAR valves (only one race!) and Ed V. cut them down for me. Actually the intake valves were new, but a set of 8 on eBay for $150 seemed like a good buy to me.

As for Andy's head and piston, we also have to remember that the bike, after injesting a lot of salt air, then took a month long cruise over the Atlantic ocean. I'll bet Andy forgot to include a 50 lb. bag of desicant in his container.

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Re: B50 MX for Bonneville

Post by Andy Chaos » Wed Feb 01, 2017 3:28 pm

koncretekid wrote:
As for Andy's head and piston, we also have to remember that the bike, after injesting a lot of salt air, then took a month long cruise over the Atlantic ocean. I'll bet Andy forgot to include a 50 lb. bag of desicant in his container.

Tom
Very true Tom.
I have given it a quick wipe with a cloth and most of the white residue rubs straight off. As for the rest of the bike it looked in better condition than it actually was. That salt is brutal especially after a 2 month cruise it is getting a total strip down clean and rebuild with new bearings pads etc.

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Re: B50 MX for Bonneville

Post by minetymenace » Wed Feb 01, 2017 3:42 pm

koncretekid wrote:Andy forgot to include a 50 lb bag
He probably smoked it after finding you can get six months in the slammer for half an ounce in Utah. <033 >44 :ban
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Re: B50 MX for Bonneville

Post by koncretekid » Thu Feb 02, 2017 2:55 pm

Scooter Grubb caught you guys in some great photography. Here's one of John, but not your best run? You gotta get down and make yourself smaller! If you go to "Scooter Shoots", you can view all the competitors at the 2016 BMST which are arranged by competitor number. Andy's bike's number is 490, while mine are 9452 and 9459.

http://www.scootershoots.com/BUBMotorcy ... /i-FfCgB5V
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Re: B50 MX for Bonneville

Post by Andy Chaos » Thu Feb 02, 2017 4:04 pm

Cheers Tom.

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Re: B50 MX for Bonneville

Post by Andy Chaos » Thu Feb 02, 2017 4:45 pm

WP_20170202_08_49_17_Pro.JPG
The rules state that the main frame loop cannot be modified (the bits that are still black)the rest has been lowered strecthed or removed
Rear top shock mounts lowered and moved forward
low profile rear tyre, seat moved back 8" lowered 3" and now fits up the crack of my arse :shock:
footrest 2" lower and moved back to 6" in front of rear spindle (as far back as the rules allow)
With the new tanks my chest (belly) is on the main frame tube.
I also have a new set of clipons that can be adjusted to point straight down which allows us to drop the front end by upto 2", suddenly the whole thing starts to feel comfy :thumb

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Re: B50 MX for Bonneville

Post by beat » Thu Feb 02, 2017 6:38 pm

:thumb :thumb

:mrgreen:

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Re: B50 MX for Bonneville

Post by Andy Chaos » Tue Feb 07, 2017 8:34 pm

The frame is back rolling. The rear shocks in the picture are 2"longer than the ones we will be using and the forks will probably be dropped through another inch. I couldn't try it with the 2 tanks as they are being painted, when they return i will check see if they hold enough fuel :roll:
This thing just keeps getting smaller :thumb
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Re: B50 MX for Bonneville

Post by koncretekid » Wed Feb 08, 2017 12:02 am

Good to see you're hard at it and making yourself smaller!. My BSA is elsewhere, so I'm forced to work on the BS which I'll take to Loring in July.
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Re: B50 MX for Bonneville

Post by Andy Chaos » Fri Feb 10, 2017 5:28 pm

Now with correct length rear shocks.
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Re: B50 MX for Bonneville

Post by Mark Cook » Fri Feb 10, 2017 6:15 pm

One has to question as to whether it is wise to run a heavily leaded fuel with an oxygen sensor. I wonder if it would upset someone's air/fuel meter?
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Re: B50 MX for Bonneville

Post by Andy Chaos » Fri Feb 10, 2017 6:49 pm

Unfortunately we have to run the fuel they give us in the gasoline class.It is true that the lambda doesnt like lead but it's usually not an instant fail. They can stand it for up to 50 + hours.
I can compare our Lambda with the one on the Dyno to see if it has been affected plus It's only a £30 item Mark so not a problem if it needs to be replaced.

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Re: B50 MX for Bonneville

Post by Mark Cook » Fri Feb 10, 2017 8:10 pm

Just a thought, sometimes I have good ones :???:
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Re: B50 MX for Bonneville

Post by Andy Chaos » Fri Feb 10, 2017 11:51 pm

All thoughts welcome Mark,we need as much help as possible if we are going to beat that 500 Norton twin. <069 B50icon

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Re: B50 MX for Bonneville

Post by HPbyStan » Sat Feb 11, 2017 12:23 am

May the force be with you,,,,,,

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Re: B50 MX for Bonneville

Post by Andy Chaos » Sat Feb 11, 2017 10:36 am

Cheers Stan B50icon
Mark i have also moved the sensor to 8" from the exhaust valve, The AFR kit is for a car and it recommends 22" but we are running a short open pipe and after seeing other similar bikes i think it's too close to the open end.
At least we are starting with a working rev-counter this year. :grin:

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Re: B50 MX for Bonneville

Post by hwan » Sat Feb 11, 2017 12:18 pm

I seem to remember that the fuel used wasn't heavily leaded - but high octane unleaded - could be wrong, but that's what i thought was supplied (are the tank sealing tapes/markers colour coded ?).

In which case, it would have have a high alcohol content, to get the knock rating up - another thing which made me think it was high alcohol was it stank of acetone - which is very commonly used as an ignition accelerator when burning a lot of alki.

Yes high lead content would have reduced the O2 sensors life - but don't forget it had done very minimal running really.
The high alcohol content would need the sensor 're-adjusting' though - and the provision is there.

As for position - it needs to far enough from the end of the pipe so its not effected by O2 sucked in, but needs to be far enough away from the combustion chamber to prevent overheating - where that is with a an aircooled engine with an open pipe ?????????

I would have thought Andy's 8" was as good a place as any ?

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Re: B50 MX for Bonneville

Post by Andy Chaos » Sat Feb 11, 2017 12:33 pm

Whan there was no guess work, the 8" came from that quick little SR500 Yam at bonneville.
I didn't have a tape with me so i layed my cock on his hot exhaust :cry:
It appears it should have been a lot closer when i measured it again in the freezing cold garage. :shock: .
Last edited by Andy Chaos on Sat Feb 11, 2017 6:49 pm, edited 3 times in total.

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Re: B50 MX for Bonneville

Post by stew79 » Sat Feb 11, 2017 4:22 pm

hi andy, can you give me the current spec on the carb you are running please, and the plug ?
thanks stew

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Re: B50 MX for Bonneville

Post by beat » Sat Feb 11, 2017 7:14 pm

hi andy

isn't your lambda sensor working with a heater inside?

mine is doing so, and it shows up when temperature is to low for exactly working....

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Re: B50 MX for Bonneville

Post by Andy Chaos » Sat Feb 11, 2017 7:49 pm

Yes Beat it has a heater and it works perfectly here in the UK and on the Dyno but either the fuel at Bonneville or the short pipe and 100+ mph caused problems. I have now moved it closer to the head.

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Re: B50 MX for Bonneville

Post by Andy Chaos » Sat Feb 11, 2017 7:53 pm

stew79 wrote:hi andy, can you give me the current spec on the carb you are running please, and the plug ?
thanks stew
Will do Stew, it a shame you didn't ask this morning as i stripped the carb to clean it.
It was spotless in side but the outside looked like it had been in a canal for 10 years. :cry:

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Re: B50 MX for Bonneville

Post by beat » Sat Feb 11, 2017 8:22 pm

Andy Chaos wrote: the fuel at Bonneville
this could be a real problem, to get to know what is the corresponding A/F value it needs for highest output.
:?: :?: :?:

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Re: B50 MX for Bonneville

Post by stew79 » Sun Feb 12, 2017 4:37 pm

hi andy, i nearly asked the question the other day after reading about the Norton 500 twin ! (b50 must beat that !) i suppose any jetting suggestions from my recorded paperwork are only relevant at sea level, but they may help ?
stew
ps did you know that in "car world" the lambda sensor isnt recording the mixture during max acceleration ? the ecu runs a pre programmed map to allow for the over rich mix needed.(but always below the best level, to reduce emissions and help with mpg) it only takes over monitoring and correcting things below certain throttle positions / rpm,s etc. all you (and me as well) are interested in is max acceleration part. (full throttle from as low a speed as it can take it, to max rpm which means its always going to be rich !)

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Re: B50 MX for Bonneville

Post by koncretekid » Sun Feb 12, 2017 8:59 pm

Andy,

Here is a photo of my A/F sensor. I don't think it's more than 8" from the head but the bike is in Colorado and trying to measure mine as you did - - I couldn't quite reach! It seems to work OK even after a few years of use on that fuel, but I can't read it once I've got my head down for the timed mile. Now if I could just get my data logger to record, I might have some answers.

Image

I think you can Google ERC 110K to find specs on that gasoline. In fact, here it is if you can read it. Maybe Hwan?
http://www.ercracingfuels.com/erc110k.htm

As for the A/F sensor and gauge being for a car, I wouldn't think there would be any difference. I think they all use the same Bosch sensor. Although it's true that car electronic control units for EFI go open circuit at wide open throttle (A/F signal no longer used), you're not using the car ECU.

Your bike is looking good!

Tom
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Re: B50 MX for Bonneville

Post by Andy Chaos » Sun Feb 12, 2017 9:27 pm

Cheers for the reply Tom
Our new sensor position looks identical to yours as for the fuel i printed off the specs last week.
Next project is to build a roller starter to ship out with the bike. I have gone for a 12v supply but will have to buy a battery when we get there as we are not allowed to fly it out so i might need someone to donate it to at the end of the week. Another bit of good news is the shipping company are offering sponsorship in the way of reduced shipping cost. :thumb

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Re: B50 MX for Bonneville

Post by hwan » Mon Feb 13, 2017 10:56 am

tom - do you reckon that the ERC 110K was what Andy was using ?

If so, it is leaded (note TEL value) - fair enough, but it shouldn't mess the sensor up though, with the mileage the engine does - mind you, it might be worth replacing with another genuine Bosch or NGK sensor?
Still burns funny though :???:

The sensors are more likely to be a problem at low rather than higher temperatures due to liquid droplets screwing things up and as for altitude - they are used in light aircraft, so?

The only thing that really helped was your advise Tom :grin:

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