HELP! 13HP transmission

[royaldragon]

I have a Winsun 13hp engine that I am putting into my Royal Enfield. I am very concerned of crank breakage as I found its vulnerability in forums after I already purchased it. So I am wondering what I should do. I have gotten the inner primary case from Henry at Pricepart, and I have a 4 speed from the Enfield. Would it benefit me to get the 5 speed that Hitchcocks has to reduce the load on the engine? I was thinking of a 6 speed ultima but I have already purchased the inner primary and i dont really want to spend a lot more money in designing a belt drive and forgeting about the inner primary that i just bought. I have also thought of a CVT. I sometimes feel like I should just stay with the 4speed but if it means a broken crank and possible engine damage than that wont work either. Pay more now or even more later. It was mentioned that maybe balancing things prior to using the engin might help.

Please, I need some help figuring this out. This is where my lack of experience is starting to get me into trouble. I'm starting to feel like having this bike done in time to ride this summer wont happen.

[Stuart]

I'm no expert and don't have one of these engines but aren't the problems associated with crank breakages usually connected with folks lightening the flywheel? There was talk of this causing those problems I seem to remember. If you leave as is I think the only problems you may have with that engine are perhaps wrongly set at factory timing (mentioned on this forum) and oil leaks. Personally I'd use what box you have as many others have done.
(to those better experienced with this engine and better qualified) does that right?

[John]

I have no experience of the 13 hp Winsun, but if your concern in mounting it is excessive load, then whatever gearbox you go with, the obvious solution is to reduce the gearbox sprocket tooth number. I have just taken my 406 yanclone out for the first time yesterday. I have a 19T gearbox sprocket with close ratio gears fitted. 4th has a theoretical speed of 61.55 mph which the engine will pull up to about 45 mph by gps. 3rd gear with the close ratio gears is good for a genuine 50 mph @ 3600 verified by satnav. My engine is rated at 8.8 bhp maximum, & 8.5 continuous. It will climb quite substantial hills in 3rd without losing too much speed & without having to fully open the tap. 4th is only of use as an overdrive in easy conditions at speeds below 45. Given some on the road experience of a yanclone, I would not now have gone taller than the 350 petrol 16 sprocket (51.83 mph by gps @ 3600) Your engine should be comfortable with a 17 (55 mph by gps)
I wouldn't go higher than that, since although it could pull more on the flat, you still have adverse road conditions to overcome. What causes most stress to a crankshaft is excessive load at unnaturally low revs. If the engine is given gearing in which it can do the job while spinning freely & easily, it should be fine. Since the crankshafts of these diesel singles are one piece forged items, rather than the weaker pressed crankshafts of the Enfield petrols, any weakness is almost certainly in the casting process. If this is the case, it will either break whatever you do, or it will never break whatever you do, so try not to worry.
Interestingly, I found that the speedometer is 7 mph optimistic, so people who thought they were cruising at 55-57 almost certainly weren't! I also have doubts as to the genuine hp of your engine, since it is of very similar capacity to the 462cc Hatz, which produces 10.7 bhp max. For any given capacity, diesels will only vary by decimal points in terms of power, not whole hp. Unless they have a turbo of course!

[royaldragon]

Thank you both for the reply. John you have made me feel a little better. Someone else told me that if my crank breaks the yanmar clones have the same crank and I can just replacement it with one of those. Now I don't know how easy it is to get my hand on a crank but I guess I will deal with that if that problem arises.

[pietenpol2002]

First, the disclaimer - my opinion may be worth little more than what you've paid for it. That said, let's all agree you're simply going to bolt things up and go. It was rumored that the 13 hp Winsun was taken out of production for a time due to broken cranks. They have resumed production of the engine, thus we might assume they've remedied the problem. If so, parts are readily available should your's "sneeze the big one".

Additionally, the chap in the link below has virtually every part you'd need at remarkably low prices. I got 2 extra cranks from him to replace a few of the tapered shafts I have, which for me is an upgrade from 406cc to 418cc. Should you utilize one of these 72mm cranks, your displacement would drop a bit as your engine uses the 75mm crank - same as the 435cc Yanmar. I believe the drill is as follows 86X70=406cc, 86X72=418cc, 86X75=435cc (Yanmar), 88X75=456cc (your engine). The claim is that the 456cc engine has precisely the same physical dimensions as the smaller displacement engines, causing me to wonder whether I could resleave or bore out one of my spare blocks to your 88mm size. Every little bit helps, you know.

Finally, if I were in your shoes I'd bolt up the transmission that's compatible and go have fun. Just be sure to carry a cell phone so that if (and it's only an"if") there's a catastrophic failure, you can call for help and most importantly, you'll have pictures over which we all can OOOOOOH and AHHHHH.

http://tinyurl.com/489a2xb

[royaldragon]

Well then! I guess I'll just hook up what I've got and go for it. Now all I need to do is compile a list of spare parts I want as they guy I got my bike from told me to make a list and he would send me any spares I want for free.
This guy Gary at novaclassics has been pretty helpful in getting me what I need. I think I am going to ask for a new gearbox as the faceplate on mine is cracked in two places and the shift peddle seems quite loose.

Thanks for all the help!!

[snoopy]

It would be interesting to hear if you can run one of these without long term failure. The extra 2.5hp would be most welcome (I run the 10.3hp 418cc).

Hitchcock's do a cush clutch which would reduce the snap load on the shaft, it's not outrageously expensive.

Running any of these engines long term at 3600 RPM is not possible (see specs) so don't be afraid to over gear. I run a 19T front with the 418cc and get 60mph average, that's without hitting 3600RPM.

[XLerate]

You might find some useful info at the linked site, though it may be some rather expensive processes. Also not sure what the exact problem is with these suspect crankshafts. I know that some Chinese steel's metallurgy is wrong as far as elemental mixtures, often with too much carbon content. This causes metal to be too brittle, yet it's very 'hard' per se. So I'm not sure if any of the treatments described at pages would offer any solution? Many suggest a first heat treating, to help align grain in metal and for deeper hardening, then followed by Nitride treatment. Don't know if any of this even applies to the engine in question.

http://www.ret-monitor.com/articles/174 ... ly-option/

http://www.ret-monitor.com/articles/545 ... ankshafts/

http://www.dsmtuners.com/forums/newbie- ... ranks.html