Footage taken from some of my rides in OZ

[andrewaust]

Here's some Youtube footage taken from a ride I took up to Paterson and back. A few have asked me for footage, I've been really slack but finally got something up on youtube - hopefully more to come, if so I'll post in this thread

www.youtube.com/watch?v=VphOefS9dek

http://www.youtube.com/watch?v=tsQgDv5lvAk


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[Sphere]

Your diesel runs really quietly Do you have to watch your speedometer to keep below 100 or can you just go all out?

[andrewaust]

Hi Sphere


Usually the old thing cruises OK at 100kph with good conditions and I do not have to watch the speedo, although on Sunday returning from the MX Nationals I opened the Enfield up and actually hit the 120kph mark on the speedo (but is that accurate), it was perfect conditions for making HP out of a Diesel, 13C and nearly 100% humidity. Don't worry (for those waving any fingers ... loll) I was in a high speed section of freeway , funny not to have cars passing me for once. It was dark so I couldn't see how many rpms I was doing, but it would have been close to redline.

The Engine is noisy at low speed, but yes I've managed to get really good power and quieten the engine from its torque curve up.

From memory I may have it set to around 17deg BTDC, but don't take that as gospel, it's written down in my logs somewhere.


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[John]

Hi Andrew. 100 Km/hr cruise & up to 120 Km/hr top speed?? From a Yanmar clone! Wow! Maybe I ought to have a re-think on the gearing of my forthcoming PricePart conversion I've commissioned from Henry. He offers 18 or 19t gearbox sprockets on his conversions, giving 58 Mph (93 km) & 61.5 Mph (98-99) respectively at 3600. Recalling my one hour experience of an Enfield Robin with its 20t sprocket, (64.8 Mph @ 3600) I felt this was way on the tall side for the Yanmar clone, since headwinds can knock a lot off the top speed even on the 18t. I decided to go for the 17t sprocket (55 Mph) which would give me something in reserve for gentle hills. But now, after reading your post, I'm seriously considering bumping the gearing way up to a 20t sprocket again. Since I have the close ratio gearset fitted, this would make 3rd an effective top gear @ 52.7 Mph @ 3600, leaving 4th as a massive overdrive ratio for gentle tooling around at 45 - 50, or for making some speed in favourable conditions. What do you think? John

[John]

P.s. 3rd gear on the standard ratio box with the 20t gearbox sprocket fitted to the Robin, only gave 47.6 mph, which wasn't practical as a usable top for any distance. Which made me more conscious of how flat 4th was as the only practical cruising gear. That wouldn't be a problem with a strong & usable close ratio 3rd as the default top, with 4th as only an occasional eco gear!

[Dan J]

John, stick with the 17t and see how you get on with it before buying new sprockets or asking Henry to make changes. I went for an 18t from Henry and that's more than enough for the bike to cope with. I have the original gearbox and the difference between 3rd and 4th does cause the engine to just slip out of its comfort zone so your close range gearbox will be a great benefit. I'd stick with what you've ordered and see what you think after 500 miles or so (will need at least this before the engine is even vaguely run in).

Make sure Henry puts the governor springs on the outside holes, not the inside ones! They are a real pig to change once the engine is on the bike (minimal distance between engine and gearbox, where the governor sits...).

[Sphere]

Why would you want to change the governor springs?

[Dan J]

It isn't changing the governor springs, it's changing the position of them. In the Yanmar engines you need the tension in the springs to achieve higher rpms and so you need the springs on the outer holes to help this. It is hard to describe without showing you on the bike but more here...

https://www.dieselbikeforum.com/view ... f=21&t=753

[Sphere]

Thanks for explaining I will read the other thread, don't think I have this on my Hatz.

[John]

John, stick with the 17t and see how you get on with it before buying new sprockets or asking Henry to make changes. I went for an 18t from Henry and that's more than enough for the bike to cope with...

'Thank you for the tips, Dan. I had already calculated that the 16t would have suited me just fine, with its 52 mph top & cruising speed at 3600. But I allowed Henry's greater experience in all this to talk me out of it & adopt the 17t. Henry had built another customer's bike there, fitted with the 17 in order to pull a sidecar. I still thought the gearing far too high for this purpose, since the 350 petrol is fitted with the 16T sprocket & develops more torque than the Yan clones at 19.7 ft/lbs vs 17 ft/lbs for our little diesel friend. The 350 petrol also develops 13 bhp @ 3600! Basically, I reasoned that an average of 50 mph up hill & down dale was all that could be reasonably expected from a continuous rating of just 8.5 bhp & perhaps 7 at the rear wheel, especially with 575 lbs of bike & rider to pull. So there wouldn't be much point overgearing the little engine & expecting it to pull a cruise speed of 60+ on anything other than a billiard table with no headwind.
After the Robin experience, & having a little diesel knowledge, I had another reason for the 16t logic. I understand how the diesel governor works in practice, & my thought was that with overload conditions removed from the engine from the excessive labour caused by over ambitious gearing, the governor would then be free to dramatically reign in the fuelling even at maximum rated revs. With too tall gearing, the engine is unable to reach rated revs under most normal road conditions, even at full 'throttle'. The governor is therefore forced to adopt overload fuelling conditions, (the 8.8 hp rated bit) pumping in all the fuel it can to get revs up to the full rated speed. With appropriate gearing for the bhp output, the engine could save fuel despite running faster revs for the same road speed. Since diesels don't need stoichometric fuel ratios to run, they are at a huge advantage in having a governor over a petrol machine!
I didn't have the courage of my convictions really, when faced with Henry's scepticism about the bike being too slow with the 16t & possessing mythical pulling power! I will take your advice, Dan, & see how the engine copes with the 17t. If it can't cope easily in pulling 50 mph in top up a very mild incline, then I'll drop the gearing back to the '350's' spec by changing the engine primary sprocket. A lot easier than changing the gearbox one! Regards, John.

[andrewaust]

Spot on Dan, the reason I obtained those speeds "and if the Enfield speedo is actually accurate " was by running the engine up to 4200 rpm "yes I have managed 120 again, but in daylight to see the tacho. The secret is to get the fuel timing and fuel delivery right. Timing is 17deg and fuel delivery needs to not be on the overfuel side, rather the sweet spot to obtain maximum power. You'll see some smoke, and I'm wondering if the governor backed the fuel off a little anyway when them rpms were reached.

The springs are set to run higher engine speeds then the recommended 3800rpm on the yanmar clones.

I'm running the 17T sprocket, and I wouldn't recommend running the engine up that high very often. If you start running 18/19/20 it will kill the top end of the engine, the torque might still be OK, but cannot really comment unless I done it myself.

The bike will not do those speeds every day of the week either, but impressive when it does

To be honest I'm happy sitting on 100khr


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[Sphere]

Did you verify the 100kph with something reliable, like a car speedo or gps navigation?

[andrewaust]

Only sitting up the clacker of the speed limited trucks, probably not the best for accuracy. I'll take more notice when I go past some of our RTA speed sign's, apparently they have no threshold and display true speed. It's funny when you approach - stay on the limit and it says thank you for not speeding, go fast and the sign goes all cranky .... PMSL !!

Road side speed readout equipment are no fun



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