salmon_slayer06 Posted August 8, 2014 Report Share Posted August 8, 2014 Installed the new V4's few weeks ago. I had the boyesen reeds and they needed to be replaced. Motor was jetted on the rich side after I built this current motor and though I'd be safe to drop main one size as well as pilot. I wanted to clean my carbs when i installed the new 4's so I did it than. So I did and noticed that she was leaner on the pilot jet on the original 1.5 air screw turns out. I had to turn it to .5 turn out to get a good rip on the throttle without there being a hesitation. I didn't think dropping the pilot one size would make it that much leaner. I figure well its good even checked plugs a few times and even when I was out on the trails. Rode great. Last trip up bike ran funny so I adjusted air screw but ended up going back to .5 turn out. Weather was much warmer than previous trip so I assumed its safe to say it should be running richer than before. I put the tools away and off I went. Not even 2 minutes down the trail I realized something was wrong. Just runniing like crap. I turned around to head back and she bogged way down, opened her up and done. Either I was plagued with the infamous melted water impeller or I ran it too lean. Coolant level didn't change and yet there was some coolant coming out of over flow hose but not spraying everywhere. One cylinder was out. At the time I figured clogged jet or bad plug connection. Swapped wires same issue. Loaded up quad and a 3 hour ride back home. Tuesday cleaned carbs, went up one on the pilot and reinstalled on wednesday. With confidence I kicked motor over with weekend plans to go riding all coming together. Nothing. Pulled plug on dead side and did the thumb over holes test.... it did blow it off. Got a compression tester and bingo..... 7 kicks no more than 30 psi. Checked other 120 ish in like 3. Motor never seized and no weird engine noises. In just the cylinder porting I have over 500 in that. Crank 400, head 250. I'm at 65.5 on bore size. I'm taking it apart this weekend to see if a top end rebuild is all I need. If its a lean issue I'm surprised. 35 keihn's pwk with a 165 main and a 55 pilot. When i had the boyesens I had 168's w/ 58 pilots and plugs were dark and just dealt with it installed new ones every trip. Motor never got hot but didn't run like i wanted till it got cooler when true colors shined. I'm probably going to get new pistons and have the cylinders just rehoned. Hoping no material got into crank. What 4mm stroker piston set should I get? The ones I have now are the vertex...... I know.... but I can't assume they are at fault till shes opened up. Sad not being able to ride this weekend. Hoping its just a head gasket. Quote Link to comment Share on other sites More sharing options...
Starwriter Posted August 8, 2014 Report Share Posted August 8, 2014 (edited) I hope you're planning to do a leakdown test before you tear it apart. With 165 and 55 jets, there's no way it's lean due to the jets. Did you do a leakdown test after you put in the VForce reeds? Edited August 8, 2014 by Starwriter Quote Link to comment Share on other sites More sharing options...
WINDYCITYJOHN400 Posted August 8, 2014 Report Share Posted August 8, 2014 You had an airleak. And EVERY post on the V-4's says "Go up one size on the pilot" If you were rich before MAYBE staying the same pilot would have worked.....but never leaner. If you are going 4 mill and not porting....get the Vito's Super Stock pistons. Then contact me from jetting needs. Next time....go ahead and start rich till you find your way to the proper tune One Change at a Tine. Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted August 8, 2014 Report Share Posted August 8, 2014 Jetting sounds good. 99% chance it was an air leak. GET THE TESTER BEFORE YOUR TEAR IT DOWN! GET THE TESTER BEFORE YOUR TEAR IT DOWN! GET THE TESTER BEFORE YOUR TEAR IT DOWN! Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted August 8, 2014 Report Share Posted August 8, 2014 All that ^ stuff Oh, and your thumb ain't a compression tester. Just because it blew your thumb off doesn't mean a thing. I was gonna continue with some analgies with blow jobs and Hoover vacs but something tells me you might already get it. 1 Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted August 8, 2014 Report Share Posted August 8, 2014 DO A LEAK DOWN TEST! Quote Link to comment Share on other sites More sharing options...
wfobasheeboy Posted August 8, 2014 Report Share Posted August 8, 2014 ^^^ DO a leak down before you tear down!!!^^^^^ Quote Link to comment Share on other sites More sharing options...
Starwriter Posted August 9, 2014 Report Share Posted August 9, 2014 All that ^ stuff Oh, and your thumb ain't a compression tester. Just because it blew your thumb off doesn't mean a thing. I was gonna continue with some analgies with blow jobs and Hoover vacs but something tells me you might already get it. 1 Quote Link to comment Share on other sites More sharing options...
salmon_slayer06 Posted August 9, 2014 Author Report Share Posted August 9, 2014 No tear down yet. Air leaks? WTF I used the crappy paper gaskets that came with the V4s and lightly coated them with gray rtv. I used one between cage and cylinder and cage and intake boot. I did check those screws about three times now to make sure they were still tight. Where else would the leaks be? I don't have more than 24 hours on this motor. Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted August 9, 2014 Report Share Posted August 9, 2014 Crank seal, intake boots, gaskets, carb. Anywhere. After the opening of the carb is considered unmetered air. A loose carb cap=air leak. A missing crossover tube= air leak. 99% of the time any thing before the bell of the carb won't have an affect. It will be minimal at best. But it can still be accounted for and corrected. 1 Quote Link to comment Share on other sites More sharing options...
salmon_slayer06 Posted August 9, 2014 Author Report Share Posted August 9, 2014 Like i said before I checked compression on both sides. The non running side was at 30 about 7 kicks, the running/ firing side was 120 around 3 kicks done at WOT. Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted August 9, 2014 Report Share Posted August 9, 2014 Okay great. Now the next test is a leak down test. It's literally 6 minutes. And can tell you all you need to know. Quote Link to comment Share on other sites More sharing options...
03DMshee Posted August 9, 2014 Report Share Posted August 9, 2014 Ill take leakdown tests for 400 alex... 1 Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted August 9, 2014 Report Share Posted August 9, 2014 (edited) The gaskets with the VF4's are actually pretty decent. Compression test only shows an air leak in the head. These motors are simple, yet if one thing isn't flat or straight it creates weird issues when sealing up. Was the bike wanting to idle higher or slow to idle back down after revving? Edited August 9, 2014 by trickedcarbine Quote Link to comment Share on other sites More sharing options...
SOUTHTHIRTY Posted August 9, 2014 Report Share Posted August 9, 2014 Bet the boots that hold the carbs were leaking. ...between boot and metal intake....after pulling and pushing after new reed installed can make them leak.. Quote Link to comment Share on other sites More sharing options...
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