Hitchcocks Forum

I might as well try it here also?
In short, my bullet has a winsun type 188 '13 hp' diesel engine. Runs well, is reliable for the last 50.000km or so.
With strong wind ahead it lacks a little power, so purchased a brand new winsun 192 '15 hp' engine fom someone who also sells enfield parts for fitting this engine, and other enfield parts

This new engine has bad cold start and has less power then the 188 engine, which i fitted again because i could not cure the new engine.
-Tappets are okay
-Injection timing is okay according to the flywheel marks, engine hammers 'soundly'.
- all i got from the seller is an other fuel pump i could try, gave no result.
-camshaft timing is okay according to the marks
-flywheight mechanism isn't stuck.

When accelerating, hardly any smoke and very low power output.
so, i am stuck with a new engine which is useless this way.
It is a very simple engine yet i cannot find the fault.

Does anyone have an idea?

Check that the throttle is opening the fuel rack up as far as it should, it sounds like the fuel delivery pump is not reaching max delivery. Also check the 'tappet' adjustment for the fuel pump, if applicable, to make sure the plunger is rising and falling as it should and as far as it should.

If the engine is brand-new, what sort of running-in procedure should be used? A few thousand kilometers on it might loosen things up enough for it to perform better, but I'm only guessing here.

As you have already been riding a diesel-engined Bullet, I guess you already know about this forum:

https://www.dieselbikeforum.com/

A performance (?!?) diesel engine for the Bullet might be one of the Kohler/Lombardini/Ruggerini twins, or maybe one of these.

https://www.globalsources.com/si/AS/Nan ... 636912.htm

A.

I saw that the bore of that Punsun diesel matches the 350 Bullet. Then I noticed the minimum order for the engine is 100! A bargain if you’ve got £79,500 and can find 99 others who want one....

Reminds me of the time I got into negotiations with a tyre manufacturer in India who was willing to make me some 5.50x16 “knobbly” tyres for my trials car. They were going to be a bargain at £45 each. This was going to revolutionise our success in off road trials competitions. I was about to commit to purchase but when the contract was sent to me it was for a minimum order of one thousand tyres! Taking into account the very small number of our type of cars needing this size of tyre and the rate of usage of the average car, I probably wouldn’t have got my money back for about thirty years.

Simple check first. Get an optical tacho, and check what the engine max rpm is set at, also find out what the manufacturer safe rpm limit is. Lister and Petter diesels came with horsepower rating charts regarding rpm/power, a Yanmar clone will be no different. An "opened up" 7 hp Yanmar will successfully propel a Bullit at 55mph all day, albeit linked to the rear wheel by CVT and a bit smokey when accelerating and climbing.

The Manufacturers power will be rated at a specific engine RPM, and will drop off below the figure, in some cases quite dramatically, so it is important that the power unit is maintaining that rpm when in use (under power) to produce the power. "Out of the crate" engines do require setting up, and before you get involved in anything difficult, check the simple things first. These engines are supplied for numerous applications operating at different RPM ratings, i.e. Cement mixers will be below 1000 rpm, whereas generators will be operating at optimum ratings of 1500, or 3500 rpm.

It might be just not run in? Obviously check what others have said but new Diesels take some time to achieve full power and fuel economy.
Also, 15 horses is really not much power. Any hill or headwind is going to make it struggle.
That 15 horses is at the crankshaft remember. You will lose some in transmission.

Duke of Wybourne. wrote: ↑

Thu Dec 24, 2020 9:49 am

at optimum ratings of 1500, or 3000 rpm.

Oops ! 3000 rpm correction

Why not 3,000 rpm, or even more - and plenty of black smoke. Just be careful how far you push things, though!
https://www.youtube.com/watch?v=y7gKbk0jyyM

Bullet Whisperer wrote: ↑

Thu Dec 24, 2020 12:01 pm

Why not 3,000 rpm, or even more - and plenty of black smoke. Just be careful how far you push things, though!
https://www.youtube.com/watch?v=y7gKbk0jyyM

No reason. I've worked a lot with aircooled diesels, and only seen one destroy itself and that was as a result of poor ring seal due to wear, and "running away" on oil blow by. You can play around with the spill timing as well once you bump up the rpm. Injecting emulsified lathe coolant via the air intake gives a better burn as well. The Robin diesels were only around 8 hp, but even they could be made slightly acceptable.