00 srx low compression?

M

motoxxman

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Sep 5, 2010
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5
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53
Location
northern CO
hey all,
so bought the 00 srx last summer , other than idleing and quick bursts, that's all i rode so far. brought to place with some land, still no snow today, but has a couple hundred yard straight shot on grassy dirt. so i did a few runs for fun. a few issues i noticed.
small bog off idle, then it hits pretty hard, front end gets light, and it starts to go, but around 30-40mph it felt like i was topped out? granted its dirt, and 60 degrees out, still that seems off? it didn't sound like i was slipping really, rpms didn't go over about 7500. i would accelerate for a bit, let off some, and then i nailed it and held wot for a good 3-5secs, and just kinda stayed around that 35mph area, no more power?? so i did compression test, and all 3 cyl read 92psi... which seems awful low! but while that's an issue? does that sound like it would cause my issue? any other easy tests to try? do? i read a little oil in the cyl and re do compression test see if it jumps up? now its the first time i used this compression tester, old one broke. so maybe bad tester? maybe clutch slipping? how to identify that from motor issue? anyway,, any help appreciated.

thanks
 

u should try to check those power valve ....not sure your compression guage work properly .....only big issue on those are those power valve and cable
 
I suspect guage problem or process problem. If engine was so wore out that comp was actually 92psi I wouldnt expect it to be exactly the same on all 3 cylinders. The other factor is COLDER air is DENSER, Sled should run ALOT better in colder temps. Carb tunning/gearing/clutching for GRASS drags WAY different than trail riding. If it ran great at 60 degress in the grass I would be scared of what it was going to do on the trail in the snow!
 
modsrx said:
u should try to check those power valve ....not sure your compression guage work properly .....only big issue on those are those power valve and cable
Click to expand...

x2 on that. check those valves and clean those carbs. need to be done annually at least anyways
 
thanks for info.. im open to think weather and ground maybe are to blame? and tester maybe not reading correctly? (fyi, to test,,i warmed up sled, then let cool for 5mins or so, then pulled all plugs, and did one cylinder at a time starting on clutch side, pulled it about 5-7 times, holding throttle wide open..anyway thats how i did testing) but i was gonna pull and clean carbs anyway,, very new to powervalves, i did a lotttt of reading on forum yesterday on tech section and posts, and while i feel good rebuilding carbs and top ends, i have to admit, the info ive read, doesnt make me feel to comfortable messing with powervalves?? not sure why. maybe once i pull apart i will get it? but not feeling confident? maybe i missed the more basic "how to " post of pulling, cleaning adjusting them?
also, a question... i lifted track , started sled, rev'd up a bit, then held it wide open for a few secs, it wouldnt go above 8000rpms.. not sure what redline is? tach goes to 10,000.... with no resistance, should i be able to red line it holding throttle open with track lifted in garage? speedo was pinned , but only 8000 rpms? hope thats normal?

thanks again all!!!
 
Old or fresh fuel? Reg or premium? Highly recomend fresh premium fuel for longevity of engine and top performance. Search "plug caps" This is another over looked performance robbing maintance we all should be checking/doing. In the one thread "a couple of bucks" postes a real nice spread sheet of what NGK abbreviations mean, Key being 5 ohm resistor.
 
motoxxman said:
thanks for info.. im open to think weather and ground maybe are to blame? and tester maybe not reading correctly? (fyi, to test,,i warmed up sled, then let cool for 5mins or so, then pulled all plugs, and did one cylinder at a time starting on clutch side, pulled it about 5-7 times, holding throttle wide open..anyway thats how i did testing) but i was gonna pull and clean carbs anyway,, very new to powervalves, i did a lotttt of reading on forum yesterday on tech section and posts, and while i feel good rebuilding carbs and top ends, i have to admit, the info ive read, doesnt make me feel to comfortable messing with powervalves?? not sure why. maybe once i pull apart i will get it? but not feeling confident? maybe i missed the more basic "how to " post of pulling, cleaning adjusting them?
also, a question... i lifted track , started sled, rev'd up a bit, then held it wide open for a few secs, it wouldnt go above 8000rpms.. not sure what redline is? tach goes to 10,000.... with no resistance, should i be able to red line it holding throttle open with track lifted in garage? speedo was pinned , but only 8000 rpms? hope thats normal?

thanks again all!!!
Click to expand...

Stock should be 8,500 rpms. Like everyone is saying, go thru carbs, clean/adjust powervalves and replace plug caps. Mine was only pulling 7,900 RPMS and after fixing/replacing everything including a complete primary clutch, it was due to a bad plug cap. Doh!
 
thanks again.. i did pull carbs today, all looked nice and clean. went through and cleaned them all anyway. i did notice my jets, 155 in 2, and 152.5 in the one, and 47.5 pilot, now one thing i guess can be a factor. sled was in midwest, and i just moved out west to CO. so was at 650ft elevation, now at 7500ft. and most of my riding will be closer to 9000ft, and 20-25 degrees F but from what i read, those are already to rich for jetting? plugs definitely had a rich look to them. from what i could tell using charts on here, and stock numbers, i should be running like 140 main jets. so ill change jets, drain and put new fuel in, new plugs, wires. and see what happens. as i said, i am hesitant to do anything with power valves right now, i just haven't seen article, post that takes me more of step by step from a stock (newbie) start. so rather be safe than sorry.
thanks again for any help!
 
Make sure you don't have a cold air kit on there before you go back to stock jetting.If you are new to srx's you may not even know its on there they look stock and you need to jet up for them that could be why your jets seem big to you. just a thought?
 
Going to have to jet it down due to the altitude change. I typically drop the mains 10 to 12 numbers when going from MN (1200') to 8000+ in WY and MT- ie 152.5's at home and 140's out west. Needles typically need to be raised (lower the clip position to raise the needle), and pilots go up to about 55's. These are obviously just examples and you will need to verify what your sled needs/wants.
 
Ahhh yeah with the rest of the story that makes alot more sense. Location says chicago and didnt say "sled came from some where else" Where (altitude wise) are you doing compression testing. Higher you go thinner the air gets and comp numbers come down.
 
in CO, so at 7500ft now for compression testing. and ya, altitude definitely will make impact, but my original issue was sled didn't want to go over 35mph while i was holding it WOT on the grass/dirt straight away goofing around.. So i just find it hard to believe the altitude made my sled equal to a kitty cat! haha... so still has to be an issue?
Yes i will be getting new jetting. but last post , guy said go richer for pilot jet? from a 47.5 to a 55? i thought i go leaner with all jets?
 
nope - pilots go up when you go up the hill. Has to do with the way the carb sucks fuel. Don't totally understand it, but that's how it goes. Needles and mains go leaner, pilots get richer when going up in elevation. And being way over on the mains for the elevation plus being 60F out for temp will make it run like a one legged dog. Not saying that's your only issue as I'm not there and its your sled, but before I started trying to find a problem that might not exist I'd get it jetted and clutched for the elevation I was using it at. Then see what it acts like.
 
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