Triumph 500 unit gearbox redneck repair

[Guest]

The distributor has its downfalls but it's just too cool. And either the plain or tach timing cover is equally more beautiful than the points in case style. (It's not a dedicated race bike, just a chopper that I had fun with the engine) I run a Boyer ei and coil, with 18d1 cap, no plug wires. Late head(slide in pipes) decked for about a point and a half.

I'd love to run a late Daytona cam, but it won't drive the distributor. I did go with the later gears so I could advance the intake on the one I have, and r tappets.

I do have Stan shentons book as well as phil Irvings tuning for speed that ones a real winner.

Figure the early plain bearing has less resistance, long as its tight enough to make oil and doesn't spin....

7200 doesn't seem like trouble. They're damn near square bore and stroke, race guys talked about going to ten. I shift too often when it stops running near nine, have yet to have engine failure just the rest of the bike, hell I've barely had both cylinders running right.

[datadavid]

7500 is a safe limit for a bush type 500, with new rods that is, i dont take mine very much above 5k since the rods are old. I have MAP rods in mind for the next teardown and overhaul, possibly a bearing conversion as well, but dont think there's any need really. Bsa A65's used the same bush with double the hp output. Of course the also benefit from a needle bearing conversion on the timing side, which is common. Some guys hard-chrome the crank end and use it as bearing inner to save material for the weak case casting. Apparently works very well.
But the main thing that let the works racers attain 10krpm was EN40 steel cranks, and a completely different valve train than what we have here.
Now im happy with the amount of torque delivered up to 4000 rpm, its very good and linear, and the 30mm wassells are almost perfect set up now. Just tried going down a step to 160 mains, will see if it reacts to throttle better at highway speeds.

I will not go flat out with this engine, until i get new rods and maybe a .040 overbore and fresh pistons. Which may or may not happen this winter, pretty happy where its at right now.

[datadavid]

Btw my cams are factory grind e3134 iirc, havent pulled the motor apart in ten years, but yes, cams can be swapped with everything still assembled basically. As long as all cams are a good fit in the cam bushings, that is.
Now, when i assembled the engine ten years ago, along with my dad since at that time i didnt know shit, it had a head that had been skimmed at least .080. With the stock cam overlap valves were all but touching the piston at the intake stroke, so we lessened overlap one cam tooth in either direction, on both cams. Now i run a stock unmilled head and a thin head gasket, but i havent verified cam timing yet as i just remembered all that. Or i remember and keep forgetting!😀
But i do seem to recall it had better bottom end torque set up like that, back then, and its bound to affect top end hp figures negatively since thats how it works on naturally aspirated engines.

[datadavid]

Ah, and my bush is not the stock copper-lead bullcrap, its a one-off machined from phosphorous bearing bronze by a local specialized brit expert. He used to do bearing conversions on these and the bsa's but he thinks the bearing bronze bushes along with modern oil filters last extremely well on the street.
Its what he prefers to sell customers, even if he would make much more money doing bearing conversions.

[Dougtheinternetannoyance123]

The nice thing about the Triumph twins is that you have a lot of options for cams, as well as you can do alternative timing unlike a BSA or Norton where its one single cam and timing between exh-intake is fixed.

Running the distributer may look cool but it handicaps you from cams, as well as a much more problematic ignition. The EI upgrade inside the Dizzy is a good idea but you are still limited. I agree the cam cover makes it look cool and I am building a bunch of static display and cut away motors out of old knackered parts and I am doing a 500 using the old style cases, cover etc.

The bushing is problematic for many reasons. Again, if there was nothing wrong with it why did Triumph delete it in the later models?
So, heres my take on Timing side bushes. I used to build a lot of hot rod car engines too,, Mostly SBC V8, but a few others and I am into Nissan and Datsun as well. Most car engines run just fine on bushes including high HP race engines. Many people rationalize this is okay for bikes too.
But thats wrong. Here is why. A car engine has 4 to 6 main bearing journals typically. Thats a LOT more rigidity than a Brit twin engine. Also the more cyls the less stressed the engine. The more firing pulses per revolution means smoother. Thats why the Japs made 4 and even 6 cyl bike engines. So, A triumph, BSA or Norton twin has a ton of flex in their design, they run a big and very heavy flywheel and engineers have documented a ton of whip and flexing of the cases. If you looked at stop motion photography of one of these engines at high RPMS you would freak out.
The only design that did it smart was Matchless - AJS as they put a central bearing support in the middle of the motor. But they mismachined and cast them so, you gotta line bore and blue print your cases to fix the misalignment. Once done though It has much less flex than a Triumph-norton-BSA.
The new Modern Norton motors use this design. I have a bunch of the prototypes here if you want to see. (plus they use a steel rod similar to a Carrillo)
So, 2 things happen to BSA and Triumph motors with bushings. They dont get enough oil, they wear, and the motor shakes like a epillectic crack whore. Now, Mettalurgy, we mentioned this before. They were sloppy engine castings when new. Tolerances were all over the place. (I worked in aerospace castings for years). But, its also a ALUMINUM engine casting so 50 years later you get some dimensional shifts and movement.
Do some blueprinting and take case halves and put on a mill and true them up and then measure. Its not uncommon to have the cam alignments off, Main bearing bores off, deck surfaces off. Often in different directions. BSA cases ESPECIALLY move around. So you gotta true them up.
I have a few tool & die and machinist buddies I trust to do this. Most backyard mechanics never check the dimensions.
So, a lightly stressed motor and RPMS kept low they do just fine with bushings on the TS as long as you change the oil a lot and take care of it.

PLEASE PLEASE PLEASE tell me you cleaned out the sludge trap and running a return line automotive filter? (Norton type) If not, you are riding a grenade. Its not *IF* you are going to blow your testicles off, but just a question of when! With a vintage engine that has not had the sludge trap cleaned it would be like taking Oprah Winfrey or John Candy and entering them in the Boston marathon or similar 10K race. They would have their hearts explode in the first mile. Your oil system is the same. Protect your Trumpet cardio vascular system!

I snapped a few pix today down in the shop,, At LEAST get a later model T140 4 valve oil pump (You will need the T140 studs,washers and nuts too) Note the difference, see the bottom nuts are at an angle? See the Ports are oval instead of round? This is a style pump I use on many builds for more flow.

ALWAYS increase FLOW,, NOT Pressure! At the risk of an oil debate,, Oil choice is critical. Also, on these engines its also critical for a good return line filter (NO Check valves or flappers, full flow only)
Second picture is what you will need if you keep revving the snot out of it, Replacement cases,,(better hurry as I am downsizing all my stuff) and the last Pix is 2 sets of late style cases,, one is open to show the bearing boss for the late style bearing.

[datadavid]

Are you situated in england Doug?
My machinist also has 5-6 complete 500 engines warming the shelf, not very popular in sweden.
I think ive cleaned out at least three sludge traps from failed cranks, because of what you mentioned, cylinder deck was not plain to begin with, and bearing housings were not aligned, so it ate some cranks before that was corrected. Funnily enough the cam bushings have always been true on that engine. And yes of course i installed a norton oil filter. Engine wear basically stopped when i intalled it. I no longer need to adjust the valves as frequently for example. I already have a spare engine, but more could be good to store since i plan on keeping and running the thing..!

[datadavid]

And i have a new oil pump with a few thousand miles on it, and excellent hot oil pressure, so thats good. Will look at map rods or preferrably steel rods, that hiduminium alloy was tough for its time but aging is always an issue with aluminium alloys, not sure if modern alloys age better, its not really my area of expertise.. but one nice thing with alloy rods is they expand up to 1mm lengthwise in service temps, effectively giving a lower starting compression and a higher running comp. Pretty neat side effect.

[Dougtheinternetannoyance123]

No, I am on the western US side, Oregon. But I have a friend from the UK who will be here in about 7 days who is shipping a container of bikes and parts back to the UK, he has some stuff stored here as well as down in California.
Got a German friend I am also storing a bike for, He comes over from time to time. Buys an old american truck that is cool but cheap, stuffs it full of bikes and parts and ships it back to Derr Fatherland. If he picked right, he often can sell the truck for good $$$$ and pay for the trip.
He has his own personal collection but wheels & deals a little to fund his addiction to old bikes. You can find him at Vetterama 1 & 2 each year. Maybe go in on a deal with him for shipping? I keep telling him a 20 foot container would be more efficient.

How many Germans does it take to change a light bulb?????????

Only one, not much of a sense of humour and they tend to be efficient.

On the rods, there IS compelling reasons to use the alloy rods from the manufacturers point of view. They are elastic for a while, (Bouncy bouncy) so absorb shock well, but like any metal or alloy they have a service life, which was my point to Sam the throttle jockey And until the last few years Steel rods had a significant weight penalty which brings up all kinds of other engineering issues. Materials have improved, so has engineering, and nowdays we can get a pretty good rod in steel without too much penalty. (DYNAMIC Balancing is mandatory). But the design is always going to be limited anyway. Its a vertical twin with a very violent design. Both rods go up and down at the same time. (on exh one intake). You can never go past a certain envelope of duty cycle with that design. Same thing with Buells,,, they dont rev, The XB9 revs more than the XB12, but either way they are done by 7000 RPM, Never gonna be a Gixxer, not gonna happen. But they are a beast from off idle to 7k and thats where the fun zone is.

[Dougtheinternetannoyance123]

The topic of RPMS and 500 twins really need its own thread, but I will touch on a few details here, Circa 2003 a good Friend of mine "Sir Eddy" called me up and said the records for Bonneville LSR were reset and rules changed. In his opinion some of the categories were wide open for new records and what was there had some soft targets.
Eddy wanted to put Norton in the record books and put together a team of people to do that. A motley crew... we are all were a bit unconventional and opinionated.
So, there was basically Eddy, Me, Fairly honest Mike and a guy named Les. All of us contributed parts, work, and ideas. But it took a LONG time and many setbacks and issues. Not the least of which Fairly honest Mike died, and so did Eddy. Eddys son Paul took over the project and I helped him get on track but in the end he got new team members and went in a different direction.
Our plan had been to sort the bike out on the road racing circuit before going to the salt. But after a lot of drama, Paul was able to get it to the Salt and set 2 land speed records. They blew the motor due to fuel starvation trying to bump those records higher.
I dont know where they are at with it anymore and I moved on to other things but last I heard they were going back again.
My name is on the front fender for a reason. I am pleased Norton holds 2 class records and I am sure Eddy is up on a cloud somewhere dancing and cheering it on.

But the details are very long. We spent a LOT of time and energy trying different ideas. But here is the basics.
We went for 500 cc vintage push rod, faired and unfaired. I donated the cases and many of the other parts but we had started with a Norton Dommi, but it was too weak, We sold that bike and started over using 750 Norton parts, and from a variety of years. Our first crank we went thru 4 cranks I had to make one good one. In the end we ended up with a Billet specialty crank as while Eddys machining was awesome, the crank we built would not take the RPMS.

So, Norton 750 combat cases, Special bearings, Special carrillo steel rods, Special crank, special cam, and a Nascar style car oil pump with multiple chambers and special oiling. No bushings and needle bearings instead with special oil feeds, Forged J&E pistons, Black diamond stainless small neck valves and special beehive springs,.
Several ignitions were tried. But to do this we had to push the RPMS way the hell up there. Our engineering brief was 11.000 RPMs and 70 hp. In order to do that, stock bearings wont go past 7,000 rpm without failure,. We had special ones fitted. The crank was rephased to a 270 deg firing order (Like Ducati) and the cases were completely blue printed and re machined so it is now a DeSaxe motor which means we changed the alignment between the bore and crank. (Offset)
Another guy came on board and did extensive spintron testing and found our cam and valve train would not work at those RPMs..(Big surprise!) so, many changes later and I think a year in development just for cams, valves & springs it does RUN but not quite to 11k like we hoped. We also were not able to get the full 70 hp either,. But good enough for govt work its still the worlds fastest 500 vintage twin.

All kinds of trick stuff, but this is why I try and educate people on what is possible and what is not. One guy who REALLY helped us out is John M, Who has a forum ID on another forum of "Dances with Shrapnel" and the reason for that is he has been building similar engines for many years and he gave us invaluable engineering help and advice. Been there, blown up a lot of stuff! I am a big fan of learning from others successes and failures, so never too late to learn something new.

Anyrate,, Thats basically one chapter in my life that took up 10 years or so.. But if you want to see the end results Sir Eddys kid put together a video..Its pretty good, see the bike out on the salt.

See:https://www.youtube.com/watch?v=Jj7KNnTpnlc

[datadavid]

We are building a reliable and relatively quick chopper here, almost as big a challenge as that lsr bike you are talking about😁
Tried it with 160 mains yesterday and it pulls much better in 4th now, no problem taking it past 70 anymore, so i think i found the mains it wants. Now just a little throttle transitions to smooth out.

[Dougtheinternetannoyance123]

I am a big fan of Mikunis, (Round slide VM type) Followed by the JRC/PKW flat slides
(Keihin type) but if Amal, then this might be helpful. Other than a restoration I prefer not to use Amals.

[datadavid]

Keihin cr's are great carbs as well, and i think they look great, usually sits on 2 strokers but they work great on the new bonnevilles.
I just really like the simplicity of mk1's, and new ones are greatly improved.

[datadavid]

Haha, i just went through my parts bin and guess what i found? I switched out a cam follower last year that was damaged years ago from a jumped pushrod, now the used follower i stuck in turned out to be a stock follower and the rest are R type. Guess that explains why its not burning equally on both cylinders. Thought it would be more noticeable.. the R type has more duration and less lift than stock. Noticed now when i was actually looking.

[datadavid]

Installed the 3.5 slides yesterday, sure livened up the old thing, much harder pull from the low end, required me to raise the needles and up the mains to 180 again. Pretty much pointless before i switch out the follower though, will probably have a whole new scenario with both cylinders doimg the same work..

[datadavid]

Took the mains down to 160, now it pulls nicely above 120, and after that clutch started slipping, also a good sign its making more power, throttle response and midrange was also much improved. And third is still very solid!