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Haflinger Engine Tune

Posted: Thu Feb 21, 2019 9:45 pm
by Garrycol
This follows on from here posting.php?mode=reply&f=7&t=11706 but is a different issue so new thread.

The engine is 762cc and with the standard NDIX Carb normally runs really well except for the minor idle issue when hot mentioned in the link.

The vehicle will pull 90kph flat out when tuned but had been loosing a little in top speed and pulling power down and a slight increase in fuel consumption- time for a tune. It has a Petronix ignition and I only use the paper air filter.

New plugs, reset timing, new airfilter and reset tappets. Carb had a complete rebuild a few years. I dismantled it and cleaned everything (was all clean) and no settings changed from previous. accelerator pump on the same settings.

Now the vehicle starts first go and now idles OK. Up to around 3000rpm it drives fine but if floored in the lower gears power seems to cut out with higher revs. (no governor). On the road it drives Ok but if you put the accelerator down the engine seems to load up and loose power but if you back off a bit it clears itself and is Ok until you put the foot down. It acts very much like it did have a governor and it was kicking in when the accelerator is forced down. (it is not like an accelerator pump issue - more like a governor kicking in) Slow applications of throttle do not cause the issue.

Open to suggestions from the experts on these engines.



Re: Haflinger Engine Tune

Posted: Fri Feb 22, 2019 12:29 am
by pinzi
Did you use bigger valves and/ or diferent camschafts?
Looks to me its strugeling to get enough air in.

Re: Haflinger Engine Tune

Posted: Fri Feb 22, 2019 1:25 am
by Garrycol
It has bigger valves but all this was done many years ago. Something has changed with my latest tinkering but I cannot work it out.

Re: Haflinger Engine Tune

Posted: Fri Feb 22, 2019 12:53 pm
by Heinkeljb
Does it hesitate if you put your foot down suddenly? If yes, it's a carb issue and that means cleaning all the jets, checking the accelerator pump, float level / fuel level.
Lack of power could be down to slightly lower compression, so a compression check might be helpful.

Timing could still be out by a little bit, cables / coil could all have something to do with it. So worth checking those carefully.


Re: Haflinger Engine Tune

Posted: Sun Feb 24, 2019 7:25 pm
by Garrycol
In lower gears it is like a governor kicking in at 4000rpm. With the throttle flat to the floor it just does nothing but if you ease off the throttle and reapply it picks up a bit and improves. In 5th gear it is just lacking power and will no get much over 4000rpm.