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TPI KTM/Husky/GasGas 2 stroke bikes
- Thread starter AlvinYork
- Start date
Some hill work to get the pipe properly hot for a change.
Sometimes on hill climbs with high load/full throttle on 3rd/4th gear the top end feels just a wee bit underpowered...I first noticed it last autumn in long, steep hillclimbs in soft sand. That was the reason why I measured the fuel pressure a while ago but it was still spot on.
Maybe I'll clean the injectors in the near future just to make sure there is enough fuel coming through. I've changed the fuel filter three times so far. Otherwise the bike starts and runs perfectly. It might also be that it's all in my head
A couple of oil changes ago I noticed that the bike had started to burn a wee bit of gear oil. It was +300 hours since I had the bottom end done so I suspected that the distance bushing on the crankshaft might be the culprit.
Changed the seal and the bushing so all is good again. Put in a new piston and backflushed the injectors as well.
Changed the seal and the bushing so all is good again. Put in a new piston and backflushed the injectors as well.
You're getting your money's worth out of the TPI
It's been a great bike and I've definitely gotten my money's worth. The 660 hours are full of good memories. Many adventures, probably about 40 races, and the bike hasn't ever let me down.
The only time the bike didn't get me back to the van was when I melted the piston and that was completely user related, not the bike's fault.
I might get a fresh 300 this year but I'll be keeping this one.
The only time the bike didn't get me back to the van was when I melted the piston and that was completely user related, not the bike's fault.
I might get a fresh 300 this year but I'll be keeping this one.
I recently did a top end at 180 hrs, IMO I should have pulled it apart at 150, it appears the TPIs are a little harder on the top end then the earlier premix motors, all else being the same, same oil, same terrain etc... I suspect the difference is in the oil inj vs premix. Everything was at max spec or a over (rings) but surprisingly compression was still pretty close to where it was when the head was installed, only about 4 psi drop. Overall no surprises and it looked good, minimal blowby. I'll take the wear rate into consideration next time around.
I've noticed the same. Compared with a carbureted 300 the rings seem to wear out approximately 10-15 % earlier.
From the 7 piston changes I've done the top ring was always close to or slightly over the wear limit (except the melted piston). But the compression was still fine.
I finally remembered to take note of the injector specs when I cleaned the injectors.
For reference: the injector is a Bosch 0280158300.
Flow rate: 251.8 cm³/min / 172.2 g/min
Resistance: 12 Ohm
The injectors are the same in TPI and TBI.
For reference: the injector is a Bosch 0280158300.
Flow rate: 251.8 cm³/min / 172.2 g/min
Resistance: 12 Ohm
The injectors are the same in TPI and TBI.
I wonder if the TBI throttle body can be swapped in, the bike runs fine (arguably better) with an injector relocation block, it might run just as well or better with the TBI throttle body. I doubt it'd be as nicely dialed in w/o the electronic PV but I suspect it'd be an improvement over the TPI.
670 something hours and the wiring loom is now starting to break at the connectors behind the headlight. The wires just fall off from the connectors. It's not a big problem to fix but it's annoying if it happens while out riding. A completely new wiring loom might be needed somewhere in the future...
I've been using the standard head or the "extreme" insert in the S3 head since melting the piston last summer but now that the spring finally came I couldn't resist putting on the high comp head. Together with a new Fresco silencer the bike pulls better than ever
What a great weekend of riding!
I've been using the standard head or the "extreme" insert in the S3 head since melting the piston last summer but now that the spring finally came I couldn't resist putting on the high comp head. Together with a new Fresco silencer the bike pulls better than ever
What a great weekend of riding!
FASTRacing
Pant Antler
Great picture ! ∆∆∆
Wall poster worthy
😎😎😎
Wall poster worthy
😎😎😎
After a fairly muddy race last weekend I took the swingarm off to grease the bearings.
Here's some footage from the race:
The hours are starting to show here and there but on the other hand the bike is also getting lighter.
I also installed the Coober head. Looking forward to testing it to see how it compares to S3.
Top left is S3 high comp insert, top right is S3 "extreme" insert, bottom left is KTM stock and bottom right is Coober.
Here's some footage from the race:
The hours are starting to show here and there but on the other hand the bike is also getting lighter.
I also installed the Coober head. Looking forward to testing it to see how it compares to S3.
Top left is S3 high comp insert, top right is S3 "extreme" insert, bottom left is KTM stock and bottom right is Coober.