Engine start problem after TSI mods

[Melba]

Hi all,
I cannot start my engine after modifying it as per TSI. I measure now 125 psi compression in each cylinder: have I gone too far? The thing is I weight 63 Kg, and my son who weights 80 kg has no problem to start the engine! Should I put 20 kg in my backpack and try again?
Happy new year all!

[Jeff B]

Just have your son give you a push.

[lost1750GTV]

Uuh, if you can start it you can ride it.
Wasn't that the rule/offer?

[Melba]

What I mean is that starting the engine is difficult for me because of the high compression, and my rather low weight: I don't have enough strength to kick the engine to a high enough speed for the engine to start, I just have my weight to counter the compressions of the 4 cylinders. On the other hand, my son does not live with me thank god for him!
So my question is: is 125 psi too high?

[Smoker]

I don't have enough strength to kick the engine to a high enough speed for the engine to start, I just have my weight to counter the compressions of the 4 cylinders.

So, you can kick it over, but it doesn't start when you do it.

Just curious if you are using the proper technique. I've seen owners repeatedly kicking away at the kickstarter, without ever winding it up to the proper starting position before kicking. There are other guys around here that have been kickstarting bikes over 50 years, and maybe they can explain better.

I've seen many types of one-person roller (paddock) starters. Also do-it-yourself kits, and build instructions, if you need them. But, if you stop on the road, you're on your own.

[Melba]

That's exactly it: I can kick it over, but it does not start. I turned 70 years old this past November 1st, and I've had my first bike, a Giulietta, at 16: I have been kicking for quite a while, and specially this RDLC I purchased in 1990! And I have this problem since I did the TSI mods and lost weight myself 10 Kg, from 70 to 60, so for me there is a clear link between the two events: increasing the compression to 125 psi + loosing 10 Kg = I can't start the bike anymore (and my son who weighs 80 Kg can) !
I've checked everything on this bike: ignition, carbs, air-tightness, valves, etc...
So my question is double: is 125 psi too much compression, and is it possible that I am too light too have enough energy too spin the engine fast enough for it to start?

[phildu31]

Est-ce que les valves d'échappement sont bien ouvertes moteur arrêté ?

[Smoker]

Good question about the valves. OP said he checked them, so I'm assuming all is well.

Your question is easy to understand.

I'm not one of the engine experts around here, but clearly 125psi on all 4 cylinders is very nice and definitely not too high for the bike.

If you're looking for someone that knows the difference in effort required to kickstart a 125psi engine vs 100psi, and whether you should be able do it- good luck. There are some extremely knowledgeable people here.

I normally don't even try to answer engine questions, but I noticed no one else has posted an answer for you. For sure I know that a lack of strength can often be overcome by good technique. That's why I asked.

[lost1750GTV]

Try different boots -
Something with a very solid sole. Maybe Mx type if you have access.
I'm not much different weight wise, and that always made a difference on 500 cc singles(2 & 4 stroke) and old ducati twins.

[Jeff B]

Worst case scenario you could have a longer kick lever made.

[Melba]

Thank's all. I will definitely check the valves. The ones I checked are the induction valves, "les clapets" in french, not the motorized ones and not the exhaust ones. The electric motor does the usual sound when ignition is turned on, but I didn't check if the mechanical links work all the way to the valves.

[rd84]

Hi all,
I cannot start my engine after modifying it as per TSI. I measure now 125 psi compression in each cylinder: have I gone too far? The thing is I weight 63 Kg, and my son who weights 80 kg has no problem to start the engine! Should I put 20 kg in my backpack and try again?
Happy new year all!

The YPVS power valves should be fully open as you kick the bike over and then fully close as the engine fires and accelerates to to its tick over speed of about 1200rpm - are you using programmable ignition like Zeeltronic or Ignitech ? These need to be programmed for this feature

[Smoker]

my son who weights 80 kg has no problem to start the engine!

Trying to help.

So, it started right up when your son kicked it over?

Did you ride it at that time, and how did the engine perform?

[Smoker]

Here you go. Compare with Wolfgang's bike being kicked (maybe 100 times).

The words at the bottom explain how they started it by pushing, but after the first start, he said it was always 2 kicks. Also explains reasons it may not be kickstarting (sticking reed valves).

Maybe you can judge if they kick faster than you? This is a race engine, and they don't seem to be kicking very hard. Mostly with the leg, not the whole body.
Stand on a box?
https://video.search.yahoo.com/video/pl ... hrmob&tt=b

[MK]

From what's written the diagnosis is pretty clear.
The owner is not able to reach the required starting rpm by kicking.

Possible countermeasures:
- 125 PSI is more or less a medium compression. Reducing it doesn't really make sense as some 95 PSI is the required minimum.
- Open/closed PV has around 0.5 bar influence (higher compression with valves in lower position)
- BR9HIX plugs may help. They usually have a better starting behavior due to the thin iridium electrode.
-DC CDI's offer a strong spark at low rpm. They usually enhance starting behavior.
- A programmable ignition would also be able to reduce advance angle during kicking. In my Pitbike this had a significant effect on starting efforts. Try both directions lower and higher advance.
- If it's the low weight of 60kg: Next to eating 2 weeks at McDonald's, how about testing a diver's lead-belt to add some more punch to your kicks? After starting you could stow it away in a tank bag.
- Last but not least: A gym can help to strengthen your legs, but this requires time and sweat.