B44 MX Motor

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B44 MX Motor

Post by Radman » Thu Dec 21, 2017 4:58 pm

I am beginning the journey into the BSA world of AHMRA Classic MX racing here in the Midwest USA. For me that almost always requires a bike "build" and that starts with a motor on the bench to discover what we have to work with.

Well I bought a couple of B44 motors in a box as parts and one reportedly good "Race-Ready" Dick Mann Built motor that had never been started since the rebuild - yea right. That turned out to be untrue as most Race-Ready claims always are. The disappointing discovery's as I tore into the motor are almost to numerous to mention here but I do have one question to float out the B50.Org community.

The head, the crank, and the case are all marked with a engraved "WM". One on each of the crank wheels and the case area just below the front cylinder. On that same note the Megacycle X8 cam was marked with a "DM" and had some alternate timing marks. Perhaps the only evidence of Dick Mann's hands ever on the motor.

Does anyone have experience with this particular WM marking - perhaps the initials of the real builder? Might it be anyone of consequence?

Obviously not critical to the project but entertaining at least.

Thanks in advance.

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Re: B44 MX Motor

Post by stew79 » Thu Dec 21, 2017 5:29 pm

hi radman, this dose sound like a great project for the new year ahead, even with the disappointing engine strip down. if you have a rough budget for all this, be prepared to add another 80 % to it, then double that amount again. (best put the same amount away for emergencies, just in case) how competitive do you want to go ?
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Re: B44 MX Motor

Post by minetymenace » Fri Dec 22, 2017 12:16 am

<135 to the forum Radman. Why not post some pictures?
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Re: B44 MX Motor

Post by Radman » Thu Dec 28, 2017 7:12 pm

Of course - pictures are coming soon.

About the cost - Duh...no need to restate the obvious...

Thanks for the Welcome and happy New Year.

Rad


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Re: B44 MX Motor

Post by Radman » Tue Jan 30, 2018 5:40 pm

Over the Holidays I was able to build a Rupert type motor stand and get all 3 motors Cleaned and stripped.

Parts are arriving daily and hopefully the reassembly process will start soon. In the mean time I have completed several smaller preparations.

Pics and descriptions to follow.

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Re: B44 MX Motor

Post by Radman » Mon Feb 05, 2018 3:49 pm

Day 1 - I brought the Dick Mann motor home that had been in the POs garage for at least 10 years
B44 Day 1.JPG
First pic attachment for me too -

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Re: B44 MX Motor

Post by Radman » Mon Feb 05, 2018 3:52 pm

Picked up 2 cores and boxes of spares hoping to build a second motor for bike 2
Second motor and spares.JPG

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Re: B44 MX Motor

Post by Radman » Mon Feb 05, 2018 4:13 pm

motor 1 came with a stand but not what I needed for a complete rework
Motor 1 bench.JPG
I followed Rubert's advice and built this
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motor stand 2.JPG

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Re: B44 MX Motor

Post by Radman » Mon Feb 05, 2018 4:25 pm

Thinks were going well but the clutch didnt look "race ready" but rather abused.
The gear box was to look similar with many gears pitted and unusable.
IMG_3106.JPG
IMG_3107.JPG
b44 clutch ohno.JPG
First sign that DM had touched this motor at one time.
IMG_3117.JPG
Note the scratched initials "DM" and timing mark

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Re: B44 MX Motor

Post by Radman » Thu Feb 08, 2018 6:14 am

As seen in the pic below the initials WM are clearly scratched into the crank wheel and into the case by the oil pressure relieve valve.

Does anyone have an idea of who this builder might be ?
Crankwheel.JPG
Crank wheel initials WM
More to follow...
Attachments
OPR Initals WM.JPG
Case Oil Pres Relief area initials WM

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Re: B44 MX Motor

Post by Radman » Thu Feb 08, 2018 6:27 am

Started the oil modifications on both motors this past weekend.
Both came out the same as seen in pics below.
Oil Mod Case 1.JPG
Oil Mod Case 3.JPG
Next order of business will be fitting B50 up-rated oil pumps.

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Re: B44 MX Motor

Post by Radman » Thu Feb 08, 2018 6:37 am

One of the side cases had a seriously ob-longed clutch arm hole in the side cover.
Some creative work on the drill press allowed fitment of a nice oilite bronz bush.
Everything lines up and feels great.
Clutch arm drill.JPG
IMG_3185.JPG

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Re: B44 MX Motor

Post by koncretekid » Thu Feb 08, 2018 1:34 pm

Please keep us posted on your progress! It's a great opportunity to see how some of the old masters did it, although I don't know who WM was, but possibly a relative. I moved your photo of the camshaft to my Macbook and lightened it up to see the new timing mark. It appears to be retarded 3 teeth from standard although we don't know if he might have introduced a new pinion gear keyway or mark as well. Please have a good look at the crank pinion to see if it shows any differences from standard, like an additional keyway.

If he retarded the cam by 3 teeth, that would be 36º which is hugely late! Let's see if I can repost the lightened photo.
Dick Mann camshaft marks.jpg
Dick Mann camshaft marks.jpg (29.11 KiB) Viewed 8960 times
Tom

P.S. Please also take some photos of the camshaft itself, especially end view showing the profiles. It's possible they had it welded up and ground new profiles. It's also possible they put a new keyway in the cam gear and rotated it, which may show up in a good photo of the keyway which is visible on the the lobe side of the cam.
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Re: B44 MX Motor

Post by Radman » Thu Feb 08, 2018 9:03 pm

B44 Crank Pinion.JPG

The crank pinion has some markings that I haven't seen in the books or my other motors - but that's not a surprise.
The Cam is a Mega Cycles "X8" and appears untouched. ( markings H 1 +)
Crank Pinion Marking.JPG

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Re: B44 MX Motor

Post by Radman » Tue Feb 13, 2018 4:16 am

Anyone know what this is...
Bearings.JPG
And I am still happily married...

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Re: B44 MX Motor

Post by Radman » Tue Feb 13, 2018 4:35 am

For oiling the top-end I considered several option but settled on this approach due to its simplicity. Since the bike will be a "racer" and never see any cold weather there was minimal use for the Oil Pressure Relief Valve (OPRV) in its current form. I read about many options and just yesterday saw the tech write-up on this approach.

I plugged the return line with a 10/32 set screw and added a spacer and tapped for a 10mm X 1mm banjo bolt (shown before tap) to route the fresh cool oil for the top-end that will be feed by a AN3 hose direct to the rocker shaft ends.
Oil Mod Case 4.JPG
PRV Rocker Feed.JPG
I would appreciate comments from anyone using or considering this mod.

As shown in earlier photos the return paths for this extra oil has been enhanced as well.

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Re: B44 MX Motor

Post by Radman » Tue Feb 13, 2018 4:42 am

This jewel (2 of them) came in a several weeks back and one was installed this weekend. I had a chance to use the other special tool built to pull it through. More special thanks to Rupert. I had to order the 5/8-20 nut to build it up.
Attachments
New Crank.JPG

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Re: B44 MX Motor

Post by B44Claus » Tue Feb 13, 2018 9:23 am

Hello Radman,
Very interesting project you a working on :thumb
A couple of comments from my side if you don't mind :smile:
The big end bearing needs a good steady supply of oil to lubricate it but just as important to provide cooling. The modification you are considering to improve top end lubrication means you will starve the crankpin/big end bearing from pressurised oil from the pump. When you remove the OPRV less oil at a lower pressure will reach the crankpin as the majority is bypassed. I know that a needle roller crank pin bearing is not relying on pressurized oil to the same extent as the plain shell bearing in the B25, but it's still a heavily loaded bearing that will benefit from lubrication and cooling provided by the oil. You want to preserve your expensive NEB crank!
If you want to improve oil supply to the valve gear you should look at a different modification:
Depending on the year of your engine there will be a small plug in the timing cover where you can connect a supply to the top end:
Top end oil modif.PNG
Top end oil modif.PNG (57.67 KiB) Viewed 8864 times
If you look in the Tech Tips section you will find the description in CCM mods and in Racing mods:
http://b50.org/techindex.htm
This modification maintains the supply of oil to your crank pin and your valve gear will benefit from a pressurised supply.
I would also fit a proper oil filter in the return line to the oil tank.

My strong recommendation is you keep the OPRV, - BSA put it there for a reason!

Brgds,
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Re: B44 MX Motor

Post by beat » Tue Feb 13, 2018 6:46 pm

hi radman
Radman wrote:Anyone know what this is...
guess engine casses in the oven...

Radman wrote:And I am still happily married...
until now, - yes.... but what will be in the future....
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Re: B44 MX Motor

Post by kommando » Tue Feb 13, 2018 8:16 pm

This is my version of the mods on the oiling

viewtopic.php?f=65&t=2948

Very similar to the ones outlined here, the pressure relief valve never operates on a roller big end as the resistance to flow is not there for pressure to rise so no need for it except on C15's. B40's and C/B25's with the bush/shell big end.

The oil going to the top end is restricted by the small clearance on the rocker spindles so most still goes to the big end, not had any big end issues with this mod and the top end is quieter with cool oil.
Last edited by kommando on Wed Feb 14, 2018 11:05 am, edited 1 time in total.

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Re: B44 MX Motor

Post by Radman » Wed Feb 14, 2018 3:36 am

Important stuff first - Beat wins - cases in the kitchen oven for bearing replacement. I will keep you posted on part 2 of your answer moving forward <201 .

B44Claus, thanks for you comments. I believe a study of hydraulics will show that with sufficient volume, pressure won't change based on where we tap into the system. Increased flow at any location will reduce the pressure for the whole system. Also note that the return bleed channel for the OPRV was plugged so there will be no bleed at that location anyway... As Kamando stated below, the internal orifices will restrict the volume to the valve-train and keep pressures sufficient to feed the crank. Dispite my 100s of searches I did not see Kamando's post on valve-train oil-feed modifications until after implementing mine...wish I had and thanks for sharing.

A couple of other items that I haven't discussed yet. I have updated to a B50 pump and will be feeding the pump from front down tube (standard) and added a small sump with strainer to feed from the rear of the main tube too insuring a constant flow of cooled fresh oil to the new and improved pump. Feeding from the back of the (new) frame should keep the sledge from accumulating in the rear of the tube - I will keep an eye on that.

Notes about the oil filter conundrum on the return line coming soon.

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Re: B44 MX Motor

Post by minetymenace » Wed Feb 14, 2018 9:20 am

Radman wrote:updated to a B50 pump
As far as I'm aware there is b-all difference on the pressure side of the B50 pump compared with the B25 etc pumps, the difference is that the scavenge side has a higher volume....or am I mistaken? What do you consider the key feature of the "update"?
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Re: B44 MX Motor

Post by kommando » Wed Feb 14, 2018 9:35 am

Wrong way round MM, feedside gear is narrower on B50 compared to B25 as with no back pressure with roller big end if the wider B25 gears were used the scavenge side can be overcome and the sump overfills. Maybe a B25 pump would work with the OPRV blocked, may try that on the next engine.

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Re: B44 MX Motor

Post by minetymenace » Wed Feb 14, 2018 1:50 pm

Thanks commando, I knew there was something about the pumps, so I still have the question what is a "B50 oil pump update"
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Re: B44 MX Motor

Post by kommando » Wed Feb 14, 2018 6:06 pm

B50 body is cast iron, B44 will be zinc alloy based.

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Re: B44 MX Motor

Post by minetymenace » Wed Feb 14, 2018 7:44 pm

Sorry to hijack the topic, were all the zinc ones two stud?
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Re: B44 MX Motor

Post by kommando » Wed Feb 14, 2018 8:59 pm

Yes zinc 2 stud and cast iron 3 stud. You only need to use the 2 studs but check for clearance for the 3rd stud boss on surrounding castings.

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Re: B44 MX Motor

Post by Radman » Thu Feb 15, 2018 5:23 pm

Regrading the oil filter conundrum...
I see an OPRV pop-off values for the B25 and the B50 in the respective shop manual but not much information about the B44 oil pressures.

Can anyone help me understand the actual "at temperature" oil pressure that one should expect on a B44. Since we are talking about ball and roller bearings only, oil pump wear might be the biggest factor in reduced oil pressure.

Noting the larger gear size and hose size on the return/savage side (for obvious reasons) I wonder what the actual pressure might be?

Any thoughts or real-world experience on this topic ?

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Re: B44 MX Motor

Post by kommando » Fri Feb 16, 2018 12:35 am

About 5 psi or less in the feedside, if the pump is worn badly the filter will stop the return flow but that's well past when the pump should be refreshed.

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Re: B44 MX Motor

Post by Radman » Wed Apr 11, 2018 9:05 pm

Getting back to work this weekend. I found a cool solution to the oil filter conundrum. I will use a K and P Engineering - S46 stainless steel screen type oil filter (http://kandpengineering.com/) The S46 recomended is quite small at 2.2" x 2.6". They claim one-inch square of their filter material flows an incredible 1.9 gallons of oil per minute at only 1 PSI pump pressure. Of course there will be many square inches in the filter (guessing about 15+) and greater than 1 lbs pressure so it should be more than adequate creating minimal back pressure. I particularly liked the small size, a magnet at the base and its cleanable / reusable. I will make a simple block type adapter that can go almost anywhere on the return line.
s46-300x225.jpg
s46-300x225.jpg (13.03 KiB) Viewed 8336 times
I put the cases together with the new crank. I degreed the cam - based on Megacycles directions / recommendations using the PES multi-position pinion gear...that was an interesting afternoon... Transmission is now together with a few new gears and a back-cut (by E & V) 3rd gear. New kickstarter springs on both motors.

I still have a few parts at the machine shop and then out to paint so i'm in a bit of a holding pattern but starting on other bits while I wait.

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Re: B44 MX Motor

Post by koncretekid » Thu Apr 12, 2018 2:45 pm

Another thread hi-jack, but I have a lingering question about suggested changes to the rocker oil feed.
kommando wrote:This is my version of the mods on the oiling

viewtopic.php?f=65&t=2948

Very similar to the ones outlined here, the pressure relief valve never operates on a roller big end as the resistance to flow is not there for pressure to rise so no need for it except on C15's. B40's and C/B25's with the bush/shell big end.

The oil going to the top end is restricted by the small clearance on the rocker spindles so most still goes to the big end, not had any big end issues with this mod and the top end is quieter with cool oil.
I tried to measure the feed side oil pressure on one of my race bikes (B50) with a cheap gauge which essentially showed no oil pressure at mid to high rpm. This was confirmed by an experiment that Beat did a few years ago where he found that the oil pressure actually went negative at high rpm. This is entirely possible, as the spinning crankshaft acts like a centrifugal pump that can suck more oil than the pump is providing, hence resulting in no apparent oil pressure, even though there is still ample flow volume. So if this is the case, then at high rpm with the suggested mods, we could get no oil flow to the rockers.

Now with the original BSA set-up feeding off the return line, there should actually be an increase in flow at higher rpm because of more oil being returned via the return side.

So the question is, is the modification really necessary? Also, if the original feed set-up including taking the feed from the spigot on return manifold and we add a return filter, can we get too much oil to the rockers as the oil filter probably increases the return side pressure? One of the reasons I ask this questions is that on my most recent B50 Street Tracker I built I use the original set-up plus a return side oil filter but I get some oil seepage around the cylinder head area which I cannot identify the source (I have re-bushed the compression release shaft). This motor is very tight otherwise and does not leak any oil or wet-sump at rest. I am using a Cometic head gasket.

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Re: B44 MX Motor

Post by minetymenace » Thu Apr 12, 2018 6:29 pm

koncretekeid wrote:So if this is the case, then at high rpm with the suggested mods, we could get no oil flow to the rockers.
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Re: B44 MX Motor

Post by stew79 » Thu Apr 12, 2018 7:41 pm

i cant see how you could get no oil pressure at high engine speed, which could starve the rockers. if it was so, some one would have picked up on this years ago. (ccm ? ) on the my S*zuki i had to make and fit a pressure relief valve (set at 20 psi) to stop the pressure from blowing the crank oil seal out. in cold weather with thick r40 it only takes about 3000 rpm to build up over 100 psi. when hot it is about 10 (slightly different oil ways to std) the pump is a much higher capacity one as it feeds the gear box shafts etc, but the crank and big end are very similar to bsa.
stew

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Re: B44 MX Motor

Post by minetymenace » Thu Apr 12, 2018 8:12 pm

I can....the spinning crank sucks more that the pump can deliver, simples....

I might split this topic if it starts to run....
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Re: B44 MX Motor

Post by beat » Thu Apr 12, 2018 8:30 pm

minetymenace wrote:So if this is the case, then at high rpm with the suggested mods, we could get no oil flow to the rockers.
yeas, IMO, this is what happened.

but we must see, as the rockers and the cam tapeds are NOT in rotating motion, they are just linear motion and this with a short time of NO forces on them. this makes as the oil will remain for a long time where it is, - in opposite to a bushing ore a bearing where the shaft rotates under load and continuously.

BTW, I do run my B 50 rocker feed off the return line and having a oil filter in place.
this filter creates a high resistance in additional to a pressure holding valve located in the return line as well.
and no issues with overlubbed rockers.

beat

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Re: B44 MX Motor

Post by stew79 » Thu Apr 12, 2018 9:31 pm

minety, i see what you mean, but the small hole diameters, rollers in the way, and small side clearance of the con rod, are all the same as many other engines. if the spinning crank of a b50 pumped more oil than the pump, this would have been spotted in the 1970,s (refer back to ccm again) it obviously needs more research with a running engine and a pressure gauge in the right place.
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Re: B44 MX Motor

Post by minetymenace » Thu Apr 12, 2018 10:26 pm

That is what beat has already done (see his posts), and that is what he observed.
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Re: B44 MX Motor

Post by kommando » Mon Apr 16, 2018 10:08 am

Next time I fire the engine up I will check this, I have a small length of clear tubing in the rockerbox feed that shows if oil is flowing so once its warmed up I will give it a handful of throttle to get the revs up high and see if the oil goes backwards. The engine has been running this mod for 5 years, oil seems to be always present in the rockerbox and no signs of wear on the rockershafts but as the bike is used on the back roads it never sees sustained hi revs which is where the issue would present itself. Mark Cooks version would also be suffering as well, maybe it's just on Beats and related to one of his many other changes.

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Re: B44 MX Motor

Post by Radman » Mon Apr 16, 2018 3:05 pm

Kommando, I look forward to your observations too.

It seems that this phenomena centrifugal oil starvation would only be present at sustained high-rpm runs like land speed record attempts or maybe road racing... Being mostly an "off-road only" builder-racer in the vintage world - I had never heard of this before?

So if that were the case, then the oil would be discharged around the connecting rod-big end at the point of highest centrifugal force? The good news - it would promote better oiling of the lower end of the cylinder / piston skirt area which I have read and heard has a problem of under oiling.

We should note the motors application: Off-Road MX and Cross Country racing so sustained high rpm runs like road racing or highway drones are unlikely. Lots of rev changes up and down as well as motion accel and braking...

Also consider the following:
1 Feeding the return line to the motor from both ends of the frame, rear upper and front downtube (brand new frame aka no sledge) providing maximum usage of all oil and all cooling the frame has to offer. There will be LOTS of oil at the inlet side of the oil pump.

2 Increased volume of B50 Pump

If the crank were able to "ROB" all the available positive pressured oil it would only be for very short bursts. The rest of the time it would be providing cooled volumes of oil that will in turn feed through the rocker shafts and trickle down over the cam lobes and followers resulting in a cooler, quieter and longer lasting valve train...at least that's the plan.

I spent the whole weekend working on a buddies B44 motor reassembly. I teased him that I was only practicing on his so I could get mine right the first time. I DID LEARN A LOT...

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Re: B44 MX Motor

Post by kommando » Mon Apr 16, 2018 4:19 pm

The B50 pump does not provide increased flow over a good B44 pump, the gears are exactly the same as the B44 but the body is cast iron not zinc so the body will not distort and the pump seize or leak profusely as the zinc one can over time. The B25 has the wider feed gears which does increase the flow when there is a roller bearing big end and not a shell bearing, it could be for sustained high revs running B25 feed gears are the solution together with a restriction in the crank feed oil gallery to provide back pressure so there is no chance of no feed to the rockerbox.

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