2018 GP300 not starting / breaking kickstarters

[Undertow]

Hi all

And greetings from Finland!

It was great to find an activ forum on GasGas. Already had great time reading through the posts.

This is my first post here and trust me, I?m going to give some head scratching for you guys

So I?ve had a GP300 for some time now, and only have been able to run five hours on the clock. Reason? The bike won?t start.

No, it is not ?it won?t crank? or ?it cranks but won?t start? kind of problem. It?s ?it barely turns over? and ?it eats up kick starters like bread? kind of problem.

When using starter it has real hard time making one revolution, like one rev per three seconds. I have changed new battery and leads to heavy gauge, and no difference.

When using kick starter there is a feeling like there would be real high compression. I have also broken three kick starters. They just give up and turn them selves over the cam when kicking. And trust me, I?m not a strong guy.

In the beginning the starter worked, slowly and loudly, but it could start the bike. But now it has no chance. The kick start works, but the last two kickers lasted few starts (the last one could take three kicks: one start, one failed attempt and on the third one it gave up).

Anyone had anything like this happening, ever?

The local importer is totally clueless.

 

[Davehuge]

Your problem sounds really strange...

Right now I would forget about the battery and electric start motor, if you're damaging the kick start then there must be some big restriction.

What about if you remove the spark plug, then is it easy to turn the engine with the kick start?

At least this will tell you if the restriction is because of too much compression or because of some other mechanical restriction.

What about the coolant level, does it lose coolant? Just wondering if the cylinder head O ring has failed, allowing coolant into the combustion camber and causing a hydraulic lock?

If it's still difficult to turn the engine with the spark plug removed, then I would remove the right side engine cover and look for anything that might be causing restriction.

I'm sure this will be something very simple but just need to work what is causing the problem.

All the best, Dave.

 

[Jakobi]

What Dave said..

Sounds awefully mechanical to me.

Something binding somewhere where it shouldn't.

If it's a new bike do you have warranty options? A dealer you can take it to?

It could be anything from the e start binding, too much compression, a crank stuffer backing out.. but one thing for sure is that continuing to try and ride like this will be doing damage.

 

[Davehuge]

If it's a new bike do you have warranty options?

Yes, it's one thing having to fault find yourself, but you shoudn't have to be paying for new parts.

Did you buy the bike from an 'official' GasGas dealer?

 

[Undertow]

The dealer is 400 km away. A small one guy company who is the official importer (small country, small motorbike factory).

Had one starter and cables in warranty, CDI is flashed (or new one) before delivery. Don?t have a good kick starter, but tried with a electric and it cranked ok when without plug. But I?ll try to use some old kickers to try with hand.

 

[Davehuge]

Yes, I can see the distance must be a problem.

Problem with using the electric start is you can't 'feel' if there's resistance.

Try removing the flywheel cover, left side of engine. With the spark plug removed you should be able to grip the flywheel with your fingers and rotate the crankshaft easily.

Let us know what you find.

Good luck, Dave.

 

[Neil E.]

Small chance but maybe the tiny compression vent hole in the cylinder is plugged up. The hole does not exist in a 250, but the 300 needs it.

You can remove the pipe and look in the exhaust port to see if the piston is scored. It should look good with only 5 hrs on the machine. What does the spark plug look like?

It sounds like you have binding somewhere. Crank stuffer bolt partially backed out? Excess bearing preload?

For a problem like this, a dealer would have to strip the engine for a thorough inspection. Take the bike to him or maybe remove the engine and ship it? Any dealer would want the whole machine to check over.

 

[Davehuge]

I"ve never noticed 'compression vent holes' ... where are they? Where do they vent to? What's the purpose of them, apart from venting compression?

 

[Undertow]

Just came back from the bike. Modified one of the broken kick starters to enable turning the engine without plug. It turns just fine. No binding, no extra noices etc.

Decided to check compression, since I now had a working kicker. Turned to be around 210 psi.

So the origina feeling that there is good amount of compression turned out to be true.

Is this enough to drain the power from starter / to have the engine kick back and break the kick start, don?t know ��

 

[Davehuge]

As I said before, this sounds really strange...

You said that the engine 'kicks back' and breaks the kick starter, is that really what it feels like?

Is it possible that the ignition timing is completely wrong, like very advanced? Could it be firing before TDC (Top Dead Center)??

But if the ignition timing was that far out then the engine wouldn't run at all, can you get it to start now?

So if you're sure there's no mechanical restriction then I guess it would be worth checking the ignition timing.

I guess there is a woodruff key in the end of the crankshaft to locate the flywheel and fix the ignition timing, could the key have sheared or be missing, allowing the timing to slip?

Just another thought...is the exhaust pipe, expansion pipe, silencer completely clear and not blocked?

 

[Neil E.]

The compression vent hole is a tiny hole located above the exhaust port. Less than 1mm in diameter. It just bleeds off some compression at kick starting speeds.

210 psi compression is fairly high for a 300. It would certainly provide lots of resistance for the kicker and estart. Many GG engines come with too wide a squish measurement. Maybe yours is a rare one with tight squish and high compression.

My 250 tests at 200 psi. It kicks over fine (and cranks OK on the estart - engine warm). The 250 piston has less surface area than a 300 piston.

Maybe some 300 owners can chime in on compression readings. And yes there is variation between models of testers. Mine has a fitting that screws into the plug hole with a 6" hose to the gauge. Compression readings are only valid for a specific engine as a way of monitoring the health over a period of time.

If most 300 owners said their machines all came in at 180 psi, then maybe high compression is your problem. If fits the scenario.

Google the method for taking a squish measurement with solder. Try it and let us know what you measurement you get.

 

[Neil E.]

If the ignition timing is too far advanced you could get a "kick back" happening. This could happen by kick or estart. There is an oval washer that locates the stator plate in it's mounting slots. If this washer is missing, the timing could be way off.

The only way to find out is to remove the cover and pull the flywheel (a special puller is required).

 

[SpirosZ1000]

I don't think that your problem is compression.A little higher comp. would be a problem while trying to start the engine cold with the starter and would cause engine problems when using bad fuel and for longer periods of use from what you are saying, not keeping you from putting the kicker down and brake them like that.
I would suggest to try some things before you end up dismantling pieces.
1st open the the radiator cap and see the level of your coolant because there is a chance ( seen it with 2018 250 model recently) coolant gets to your combustion chamber and causing hydraulic pressure (effect).
Solution open your cylinder head and inspect the o-rings and while you are there inspect the cylinder for cracks( rare occasion but could have happened for many reasons)
2nd take the spark plug off (observe it) and try turning the engine with your hand over the plug hole to see if anything liquid comes of other than gas (not much) Maybe for some reason your engine overflows with too much fuel.(not so likely)
3rd something is binding. Take the front pipe of and watch your piston for anything unusual. (scorches, broken piston rings or out of their place).

Report what you find and hope you find it soon.

p.s. In case you need cylinder head o-rings try from KTM same bore.
Gas Gas o-ring weren't the best at least the older ones but KTM's are thicker and work great with less problems.

 

[Davehuge]

Just came back from the bike. Modified one of the broken kick starters to enable turning the engine without plug. It turns just fine. No binding, no extra noices etc.

So if it the engine turns fine without the spark plug in, what happens when you put the spark plug in? Is it immediately difficult to turn the engine?

Did you check the coolant level? Are you losing any coolant?

Have you started the engine? If so how does it run?

The more I think ahout this problem, the more I think it will be something very simple to fix, the difficult bit is finding the problem...

Good luck, Dave.

 

[Davehuge]

I was just thinking...

Are you sure it's not something crazy like your carb overflowing into the crankcases, flooding them with fuel, then causing a hydraulic lock in the combustion chamber?

If this was happening then I'm sure you'd smell petrol strongly and when you removed the spark plug it would be spraying fuel out of the spark plug hole when you turned the engine.

Really starting to grasp at straws now...

 

[Davehuge]

You said you've broken 3 kick starters...WOW that must ge some big force you're kicking against...

If it's not a mechanical restriction and something is really causing a very high compression, then I wouldn't run the engine... you could easily damage the crank.

Good luck, Dave.

 

[Neil E.]

How did the engine sound when it was running? Free reving or struggling?

I'd expect to break a kickstart lever you'd need a broken piece of clutch plate floating around in the right side case. It would have to jam the primary gears.

 

[gasgasman]

Using the wrong transmission oil can break kick levers.
The kick start sprag gear can bind from not sliding together.

 

[Undertow]

Some answers for very good suggestions:

- The coolant level is ok. Hydro lock would have been a good answer, but not this time.

- After putting the plug back the engine gets hard to turn right away.

- No extra fluid (water / petrol) coming out of the plug hole when turning the engine.

- No extra noises (as said before) when running, but really crappy running at lower rpm's and strong kick later, like my TE125 (original needle, and through this forum I know what to do, thnx).

- Have to look for the vent hole. A new one for me too, but if there is one it could be the reason (the starting got worse and worse until stopped totally).

- If the oil is to blame then the original oil is wrong one. The first kicker broke around 2 hours of riding.

- The design of the kicker is bad. The cam on the kicker puts forces in place that can't hold it well. All three have failed the same way as the one in the picture (see attached pictures). Just today got a new one with different design, this looks like it will hold better (the third picture).

- Maybe I'll install the kicker, get a new battery and try once more.

 

[Neil E.]

It's normal for the heel of the aluminum lever to deform a bit. Your pictures show a poor match on the parts, I can see how those would break. The new lever and mount look much better.

I'd like to know what squish measurement you get. The motor should not be that difficult to kick over.

The compression vent hole is in the cylinder bore near the top. It's just a tiny little hole that allows some gasses to pass out into the exhaust. It's only effective after the piston rises above the exhaust port. Too small to mean anything when the engine is running.

You'll only see the hole when the cylinder head is removed. Maybe someone with their cylinder currently removed can tell us if the hole can be seen when looking in the exhaust port (from the outside). If so, with the piston at BDC you could see if a thin wire can pass through.