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EC/GP 300 2018/2019 Power valve adjustment

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Those of you who have tried different set ups what are your experiences?

I have tried all set ups in half turn increments and ended up wit 1.5 turns open (factory set up 2 turns open). It may seem strange or dumb or whatever but I have the impression that if open the adjuster (ccw) further than 2 turns that I get LESS torque but a revvier engine. Is that possible :excuseme:

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10 minutes ago, Doc Brown said:

...I have the impression that if open the adjuster (ccw) further than 2 turns that I get LESS torque but a revvier engine. Is that possible :excuseme:

I haven't played with the adjustment on the GG bikes but what you're saying makes sense. If you reduce pressure on the pv then it will open earlier, making the engine rev quicker, but at the expense of low end torque.

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1 minute ago, SS109 said:

I haven't played with the adjustment on the GG bikes but what you're saying makes sense. If you reduce pressure on the pv then it will open earlier, making the engine rev quicker, but at the expense of low end torque.

That's the way I understand it but I am not sure if that is really correct as the description in the owners manual let's room for different understandings.

Let me go and get a pic and then come back, that will probably make it easier to understand what I mean.

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Here we go:

36867427ip.jpg
 

Lets just talk about 1.5 turns where it says or means it will provide a smooth power delivery t on surfaces with low grip. My impression is that it has a lot of torque with this set up and that is contra-productive in my opinion. Sometimes when riding with lower revs in second gear and then opening the throttle I think its too much so what I do is short shift in third which makes it much easier but sometimes, when I need power quickly not much happens.

Maybe it would be worth a try to go to 2.5 turns to get a revvier more responsive engine with less torque. The explanation above is a bit weird in my opinion.

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That chart states that 1 turn on the power valve equals 14.2mm spring preload and 3 turns equals 15.8mm preload, so they must be turning the preload nut IN and not OUT (Open or CCW). Seems like that chart is backwards because as you stated more preload on the adjuster should require higher RPMs to open the power valve and this would yield more low end torque since the power valve would stay closed until the RPMs climbed higher.

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I opened another thread for my last questions about the PV. I tested 2.5 and 2.75 turns open and both felt better than the 1.5 turns that in my opinion produce too much torque at low revs. That makes it hard to control on slippery surfaces like wet rocks and stones or roots. It felt much better for me and I ended up with 2.5 turns. Together with the soft (or retarded) ignition curve its really smooth. Only downside is the higher fuel consumption in "rain" mode.

I will try that tomorrow again and see how it goes...

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After a lot of testing the last two days I can say I found the (for me) best adjustment and I am very happy now. 2.5 turns open is what transformed my and my friends bikes. Both bikes (GP and EC 300) produce torque now much smoother and are easier to ride. I just need less concentration in difficult terrain.

I don't know if my English is good enuff to describe what changed but I'll try. When the PV was set to 1.5 turns I did not use the first gear, not even on very steep climbs as it was -in my opinion- too aggressive. Second was always good at a certain speed but if I needed to climb slower I had to use the clutch a lot which was difficult sometimes as the engine produced tons of torque and keeping the front wheel grounded was a challenge. Most difficult to find the point of good traction and an airborne front wheel.

Now I use the first gear almost everywhere where a slow climbing speed is necessary and I don't use the clutch so much. Still use it when necessary though. The slower climbing speed gives me more time to find a good line and I save quite a lot of power. Yesterday we did lots of tricky climbs on partially quite loose ground and it was so much easier to do it slower with less wheel spin. We tested from first gear to third gear, second was fastest once we knew the ideal line, third was a pain, especially for the clutch. In first it was easy. So I'd say if its steep and tricky and I don't know what's coming next (obstacles, logs, branches) first is my choice. Then if I do the same climb again and I already know what's coming I'd use second with more speed...

I am really happy how my Gasser performs, it's really astonishing what a single turn on the PV adjuster can change.:ride:

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Based on you bringing this up Doc, I played with mine a bit yesterday, I had been running it at 1.5 turns, but brought it out to 2 and I liked it better. 

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59 minutes ago, Jetster220 said:

Based on you bringing this up Doc, I played with mine a bit yesterday, I had been running it at 1.5 turns, but brought it out to 2 and I liked it better. 

That's great to see that you too got the same positive impression 👍

We, my riding buddy and I were both following an advice and set it to 1.5 turns first.  But we only tested it on a fire road as we have no play ground around. We should have tested it in real terrain but we did not until this week.

Most friends I talked to did not understand the causal relationship between power and torque as they ride 4 strokes and there is not much you can adjust. But they understood it after I explained my example with two cars, both with just 68 hp, one a turbodiesel the other a common gas engine. Then try to accelerate as fast as possible on a wet, slippery road. The diesel immediately struggles as it has so much torque down low, the other car just is to weak to let the wheels spin a lot and will reach the same torque at 5000rpm, that's about 400rpm after the diesel engine would have exploded :-)

Never mentioned it, but I don't understand that many GG-300 riders buy a FMF Gnarly to get more low down grunt. All they need is to close the PV to 1.5 turns and they get what they want for free....

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Doc, I am going to try your 2.5 turns out this weekend. I have been of the mind set that 1 or 1.5 is better for tight/technical stuff. The torque does get to be a handfull at times. I'll post how it felt Sunday.

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1 hour ago, jgl1962 said:

Doc, I am going to try your 2.5 turns out this weekend. I have been of the mind set that 1 or 1.5 is better for tight/technical stuff. The torque does get to be a handfull at times. I'll post how it felt Sunday.

Hey cool! I am really looking forward reading what you experienced. All started when I was talking to a guy who said the description is somewhat halting and does not really explain what's going on.

I had the adjuster turned back from 2 turns to 1.5 turns and thought I will get a softer response from fully closed throttle. I did that because the manual says "1.5 turns for smooth power delivery". The truth is, it was harder to control, for me it had too much(!) torque at low revs. My riding buddy, who also had set the PV screw to 1.5 turns tried my bike and immediately changed his adjuster to 2.5 turns too. He confirmed what I felt and also said its much easier to control in the slow, tricky stuff where you roll downhill slowly in second, throttle closed, run into a dip and need to open the throttle for the next climb with slippery surface. It just pulls super smooth, requires a tad more throttle now.

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Doc,

I moved mine from 1.5 to 2.5 turns out and I have to say it did smooth out the bottom a bit. I did some slow figure eights and full lock turns around obstacles on wet grass. Definitely less "abrupt".

Flip side is and it's a good thing once you get used to it, the thing is a beast when it wakes up. I actually turned it back to 2.25 to take a little hit out (I'm old 🙂 ).

We did a Hare Scramble Saturday and the whole course was grease with mud holes mixed in. The bike would go, it didn't want to steer though. It did crawl up the few hills on the course with zero slip. I give the PV adjust and the AT81 EX credit for that.

Thanks for the tip 🙂 

Jim

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Hi Jim

Thank you for reporting how things went 👍 

Exactly what we both felt too. I am sure you can tune it to get your "personal sweet spot". I will probably too get back to 2.25. And yes, I am old too 😉

We rode on a -for us- difficult track on Saturday and felt it helped on wet rutted climbs to keep the rear wheel from spinning too much or going uphill slowly and trying to pick up speed...

Glad you liked it :-)

Doc

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