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Enduro Engine - 2 stroke Cylinder, Piston, Tranny, Bearings, Clutch, Pipes & Silencers, etc.


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  #11  
Old 11-08-2018, 09:31 PM
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Jakobi Jakobi is offline
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I don't have anything against technology.. You can't dispute the advantages that they offer. I wouldn't want an inefficient fuel guzzling carby fed vehicle as my daily driver!! However that is the point...

My dirtbike isn't my daily.. I don't give two hoots about it's emissions. I want simplicity. I want it to be cheap, easy, reliable...

In saying that, many mates are getting around on fuel injected 4T's without issue. The occasional dirty injector/filter causing some starvation issues, but nothing too bad.. 2T technology will probably get to the same point.. but I don't think it's there just yet.. The old carb is pretty tried and true. I'll change at some point.. but not just yet. Leave it for the Jones' to do the r&d.


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  #12  
Old 11-09-2018, 11:30 AM
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The Tpi technology will deffo get there but at the expense of many riders pockets, I have been told of pistons needing changing at 20 hrs because they are running so lean, the ones I have tried feel disconnected, no feeling of reaction to throttle amount... so while I can keep a carb I will, even at the expense of being ripped by my mates for buying a gasgas..........
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  #13  
Old 11-09-2018, 01:10 PM
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The problem with the KTM TPI is not the fuel injection but the oil injection. It's a crude lash-up of a solution that reminds me of their approach to 2 stroke starter motors.

The USP of the 2 stroke has always been that it is a simple motor principle run on pre-mix oil-in-petrol fuel. Cheap to own and maintain and easy for home mechanics to keep on top of. Its Achilles Heel is that forgetting the oil is fatal.

KTM has then gone and produced the worst of both worlds by making the 2 stroke engine as complex as a 4 stroke whilst leaving the oil injection side prone to all kinds of issues. The initial bikes had oil tanks make of brittle plastic that cracked and dumped the oil as there was no vibration damping for the bolts. Then the rider needs to check the oil feed pipes for air or the pump stops delivering oil and needs bleeding. Or the oil pump just gives up. All this with the rider only realising what's going on when they hear expensive metal on metal noises.

Oh, I nearly forgot.... it has added 30% to the price of a 2 stroke KTM. Result!

The solution may be either to inject premix or for some kind pre-injection buffer where the oil and petrol are mixed immediately prior to injection to allow the oil ratio to be varied to match the engine load and reduce emissions.
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  #14  
Old 11-09-2018, 01:21 PM
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Quote:
Originally Posted by RudolfHucker View Post
The solution may be either to inject premix or for some kind pre-injection buffer where the oil and petrol are mixed immediately prior to injection to allow the oil ratio to be varied to match the engine load and reduce emissions.
If the oil pump is root cause of the problems and it's difficult to monitor it's operation, not able to give any warning, then surely just reverting back to a Premix setup would be a good solution.

It'll be interesting to see what KTM's solution is, it would be a terrible embarrassment to have to admit a design error.

It would be good to get an idea of how many engines have been affected, what percentage, but I guess KTM will be keeping that very tight to their chest.

If this oil pump situation is as bad as it sounds, then I guess GasGas are happy they decided to wait. Who knows, GasGas may decide to go with FI but stick to Premix and not bother with oil injection, tank and pump.
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  #15  
Old 11-09-2018, 03:16 PM
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Beta went half and half with a carburetor and oil addition via a pump. Not without problems, particularly with air in the oil feed lines. At least you could block off the oil fed and revert to pre-mix.

One thing you can say is that the Betas do run pretty well and at oil ratios around 1:100 on low engine load so emissions are improved over straight pre-mix. The oil side still seems to be the weak link.

I don't know if you could use an existing petrol injector to inject pre-mix as I imagine the oil affects the density and mist qualities of the fluid. Perhaps you might need something more like a diesel injector. That's another area of product development and cost.
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  #16  
Old 11-09-2018, 06:49 PM
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Quote:
Originally Posted by Davehuge View Post
If the oil pump is root cause of the problems and it's difficult to monitor it's operation, not able to give any warning, then surely just reverting back to a Premix setup would be a good solution.



It'll be interesting to see what KTM's solution is, it would be a terrible embarrassment to have to admit a design error.



It would be good to get an idea of how many engines have been affected, what percentage, but I guess KTM will be keeping that very tight to their chest.



If this oil pump situation is as bad as it sounds, then I guess GasGas are happy they decided to wait. Who knows, GasGas may decide to go with FI but stick to Premix and not bother with oil injection, tank and pump.


You can’t run oil through the injector. It’s just too thick and won’t go through the tiny holes need to build fuel pressure

I am a member of a TPI owners group on FB and the failed oil pump problem shows up weekly. It’s not the only issue they are having either. They are having issues with the oil tank cracking at a seam. Also The mapping from the factory is all over the place, some are super lean, some so rich they won’t run. My buddy has a Husky TPI with an RK Tek and that bike flat out rips but I still worry the oil pump is going to fail on him


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  #17  
Old 11-09-2018, 06:56 PM
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Here’s a few more screenshots.



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  #18  
Old 11-09-2018, 07:03 PM
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Oil tank cracking on a seam... surely that's pretty easy to fix, ask the company that manufactures the plastic tank to move the seam to a different position and or add rubber mounts to take any stresses out of the tank, then send replacement tanks out to all dealers.

What's the big deal with the oil pump? I've owned many road going 2 strokes from the 1980's and 1990's that use a mechanical oil pump to deliver 2 stroke oil. Never had any problems with the oil pump failing or air in the oil feed lines.

Any comments from KTM?

Not sure about photos on social media showing pictures of mashed up pistons and barrels, they look very spectacular but don't tell us much as we don't know what happened before the event. It would interesting to know about failure rates, how many of these engines have failed? That would give people a better understanding of how serious the problem is.

Of course, with all these stories flying around, I wouldn't be rushing out to buy a TPI bike. As people have said before, the research and development should be done in the factory's R&D department not by the customers.

Last edited by Davehuge; 11-10-2018 at 03:41 AM.
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  #19  
Old 11-10-2018, 03:38 AM
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Is KTM paying to repair or replace these blown engines or are they just pointing their long suffering customers to the local scrap metal dealer?

It is interesting that Beta are offering a Steve Holcombe Replica to celebrate his recent World Enduro championship that runs on pre-mix. They obviously don't trust their own oil injection system when the chips are down and the company's reputation is at stake. There were lots of stories going around when TPI came out that the KTM and white-painted KTM riders refused TPI and stuck to carbed bikes for as long as they could.
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  #20  
Old 11-10-2018, 04:22 AM
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A friend of mine has a Beta 300 2017 its done 70hrs ish, out on a ride and it seized solid, we got it back and after investigation the diodes that control the pump failed because of water getting to them, he went back to the dealer and hats off to them they paid 75% of the cost to repair the bike, he has now disconnected the pump and started running on premix...
Talking to a KTM tech guy at the dirtbike show and he was telling me they are going to see major improvements of the TPI system on the new bikes in June next year, it seems to be a bit like the issues they had with the 350s when they released them first off, I had 2 x 350s that kept failing due to injection problems, but to fair the 2018 I have just sold was very good but it didnt suit me...
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