Platinum Contributing Member Skidooski Posted March 25, 2019 Platinum Contributing Member Share Posted March 25, 2019 10 minutes ago, Carlos Danger said: the irony of two strokes is most times the radically ported engines run lower compression on a gauge. An engine with stock or even low hp porting will in most cases read higher on cranking compression.. None of you guys run a Leak down tester? Yep, depends a lot on exhaust port roof height. The less of an effective stroke the less volume there is to compress Quote Link to comment Share on other sites More sharing options...
Platinum Contributing Member Skidooski Posted March 25, 2019 Platinum Contributing Member Share Posted March 25, 2019 15 minutes ago, 1jkw said: Holy shit, what octane do you need to run. Switching back to VP fuels so I'll probably start with C14 or maybe C14+. I want to double check comp ratio and static timing first Quote Link to comment Share on other sites More sharing options...
AKIQPilot Posted March 25, 2019 Share Posted March 25, 2019 A 2011-2016 IQr had about 155psi of compression stock. Obviously that varied by gauge but the stock IQr had decent compression stock 135-140 isnt bad. Depending on your technique for the test that could be up close to 150 using a different gauge. Quote Link to comment Share on other sites More sharing options...
Winterman Posted March 25, 2019 Share Posted March 25, 2019 Quick story i know a guy that had a 2015 Rush 800. End of season he decided to check compression. He removed both side panels and the hood (including key switch and gauges). Taped throttle open, removed one plug and left the other one in. He hooked up the compression tester in the other hole. First pull, the thing starts up with approximately 75 very angry horsepower. It takes off with impressive speed straight through a grape arbor about 75 yards away. After the grape arbor it continued about 1/4 mile through a farm field to the neighbors house. It smacked a parked Pontiac and ripped the entire front bumper cover off of it then cartwheeled across his driveway. It came to rest upside down and still wide open screaming. Good times. 2 Quote Link to comment Share on other sites More sharing options...
Platinum Contributing Member Skidooski Posted March 25, 2019 Platinum Contributing Member Share Posted March 25, 2019 Holy crap! Nope pull all the plugs, just makes it easier to pull the motor over, flip the kill switch and remove the tether Quote Link to comment Share on other sites More sharing options...
Zambroski Posted March 25, 2019 Share Posted March 25, 2019 4 hours ago, Skidooski said: Holy!!!! 110? 3 hours ago, Jimmy Snacks said: Cold compression...didn’t hot....look good? Giv’r! Now that you’ve done it, you can do it mid season. I like to pull the plugs and see how they look then give each hole a quick test. 1 Quote Link to comment Share on other sites More sharing options...
Platinum Contributing Member Jimmy Snacks Posted March 25, 2019 Author Platinum Contributing Member Share Posted March 25, 2019 15 minutes ago, AKIQPilot said: A 2011-2016 IQr had about 155psi of compression stock. Obviously that varied by gauge but the stock IQr had decent compression stock 135-140 isnt bad. Depending on your technique for the test that could be up close to 150 using a different gauge. That was cold, throttle wide open, 6 pulls. 1 Quote Link to comment Share on other sites More sharing options...
1jkw Posted March 25, 2019 Share Posted March 25, 2019 18 minutes ago, Skidooski said: Switching back to VP fuels so I'll probably start with C14 or maybe C14+. I want to double check comp ratio and static timing first My friend has a HTG 1000 XCR based engine, he thought it needed c-14 it would hardly run and was hard as hell to start, he finally mixed the c-14 with non eth high test and it ran much better and started easy. He did a compression check it was only 135, but I guess it is really the comp-ratio that matters though. Quote Link to comment Share on other sites More sharing options...
Zambroski Posted March 25, 2019 Share Posted March 25, 2019 27 minutes ago, Winterman said: Quick story i know a guy that had a 2015 Rush 800. End of season he decided to check compression. He removed both side panels and the hood (including key switch and gauges). Taped throttle open, removed one plug and left the other one in. He hooked up the compression tester in the other hole. First pull, the thing starts up with approximately 75 very angry horsepower. It takes off with impressive speed straight through a grape arbor about 75 yards away. After the grape arbor it continued about 1/4 mile through a farm field to the neighbors house. It smacked a parked Pontiac and ripped the entire front bumper cover off of it then cartwheeled across his driveway. It came to rest upside down and still wide open screaming. Good times. I’ve heard a few stories like that. Usually they end up t-boning a vehicle or into the side of the barn. Smh. ”It was that damn other cylinder!!!” Quote Link to comment Share on other sites More sharing options...
Ez ryder Posted March 25, 2019 Share Posted March 25, 2019 56 minutes ago, 1jkw said: Holy shit, what octane do you need to run. I would guess,he runs c116 Quote Link to comment Share on other sites More sharing options...
Platinum Contributing Member Skidooski Posted March 25, 2019 Platinum Contributing Member Share Posted March 25, 2019 14 minutes ago, 1jkw said: My friend has a HTG 1000 XCR based engine, he thought it needed c-14 it would hardly run and was hard as hell to start, he finally mixed the c-14 with non eth high test and it ran much better and started easy. He did a compression check it was only 135, but I guess it is really the comp-ratio that matters though. Comp ratio and timing advance are the two big things. What it pulls on the rope doesn't as mean much when it comes to what fuel to use. If you have a high exhaust port duration you can have high compression ratio and still have it read lower on a comp gauge Quote Link to comment Share on other sites More sharing options...
1jkw Posted March 26, 2019 Share Posted March 26, 2019 44 minutes ago, Skidooski said: Comp ratio and timing advance are the two big things. What it pulls on the rope doesn't as mean much when it comes to what fuel to use. If you have a high exhaust port duration you can have high compression ratio and still have it read lower on a comp gauge I guess the pipe scavenge or charge probably boosts the poundage when running at peak power band too. Quote Link to comment Share on other sites More sharing options...
racer254 Posted March 26, 2019 Share Posted March 26, 2019 I went down and checked mine. Both running right in the middle between 130 and 135. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.