Thrusted Vector
Expert
Big Dog here's another way that is easier to check the valves,a compression test or a leak down test.A leak down test is more accurate.
rxrider
Jan-Ove Pedersen
- Joined
- Apr 25, 2003
- Messages
- 7,355
- Age
- 59
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- Lakselv - 70N & 25E
- Country
- Norway
- Snowmobile
- 2014 Phazer XTX, 2013 Phazer RTX, 2008 Apex RTX, 2007 Warrior, 2006 Attak
Are you positive that your pilot jets are clean? That popping makes me think of a lean condition. Have you tried larger pilot jets, it will feed more fuel thru all throttle positions. 15 pilots are really small and are easily clogged with whatever dirt that passes thru those jets. I've had that happen one time even with 17.5 pilots.
treewhacker
Expert
wouldn't a compression check show leaking valves also? Easier to do than dissasembling the engine too.Thrusted Vector said:Check your valve clearance,if the exhaust valve is held open at all it will do this.It's not hard to dne of two things will happen soon,either a burned exhaust valve or worse a dorpped valve,if you don't eliminate an open valve.
Thrusted Vector
Expert
Right,you can check to see if you have burned an exhaust valve with a leak down test.Which will make it sound like it's running lean.If the sled won't idle right,popping at idle about 1500 rpm and soon as you try to raise the idle then all of a sudden it won't idle down right away.
Mine did this the first few rides, I was getting frustrated with it messing with this, adjusting that, finally tracked it down to the fuel pressure being set too low, turned it up to 5 lbs. no problems last 5 rides. 
ken_climb
TY 4 Stroke Junkie
We are on a roll here,Mine has been running very rich like when I get to our play area at 6-6500' tons of lag and when it does kick in then if I let off (even slowly) and then apply throtle again it has a very slow response and hickups like it super rich. Seems like I have to lean everything out but I don't know why it would need to be since it was running great till christmas? I am getting some moisture in the intercooler so then it gets in my carbs to,I'm LOST! cause when I headed down to the truck at lower elevation it ran like a missile,no lag just mental fast!
Otis RX
Expert
What are you running for a fuel mixture???
I found that running too much c-12 at low boost caused bad popping.
I'm running 12# and run an exact mixture of 50% 93 Mobile and 50% C-12.
Still "a little"popping at very low speeds but none at Low MID- WOT.
Drop the boost and you can cut back the C-12.
I've never run straight 93 as my riding is mainly confined to lake runs.
IMO...... the turbo requires new thinking on fuel. Buy the best 93 you can find. Track your mixtures and write them down. Mix in a real mixing jug where you can be exact! I stay away from 93 with additives like MBTE and ethanol. A turbo is creating a new level of combustion that is more sensitive than your standard 800cc 2 stroke. Think about it! Stick with the 400 jet in the pitot tube at 8# and up.
My 2 cent
OTIS
I found that running too much c-12 at low boost caused bad popping.
I'm running 12# and run an exact mixture of 50% 93 Mobile and 50% C-12.
Still "a little"popping at very low speeds but none at Low MID- WOT.
Drop the boost and you can cut back the C-12.
I've never run straight 93 as my riding is mainly confined to lake runs.
IMO...... the turbo requires new thinking on fuel. Buy the best 93 you can find. Track your mixtures and write them down. Mix in a real mixing jug where you can be exact! I stay away from 93 with additives like MBTE and ethanol. A turbo is creating a new level of combustion that is more sensitive than your standard 800cc 2 stroke. Think about it! Stick with the 400 jet in the pitot tube at 8# and up.
My 2 cent
OTIS
treewhacker
Expert
Where do you check the fuel pressure? I didn't know it was adjustable.
On my Bender, where the 2 lines come out of the regulator and goes into 2 T's. Both tees branch off too a pair of carbs and to the stock fuel pumps.
I disconnected one branch that goes to the stock pump and inserted a machanical fuel pressure guage.
This was to check fuel pressure @ idle and low RPM on a stand. But you could connect another T between there and the old stock pump and run your guage up to the dash area. Or just bypass the stock fuel pump all together, except you would loose lip home mode if something happened to electric pump.
I disconnected one branch that goes to the stock pump and inserted a machanical fuel pressure guage.
This was to check fuel pressure @ idle and low RPM on a stand. But you could connect another T between there and the old stock pump and run your guage up to the dash area. Or just bypass the stock fuel pump all together, except you would loose lip home mode if something happened to electric pump.
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