holes drilled on stock air filter problem

meatgrinder

meatgrinder

New Member
Hi guys, my motor pk66 is riding fine, great little thing. Performed plug chops to see if im running rich or lean (running 24:1 cheap 2t oil and had the needle c clip at 2nd to top setting) Checked the plug and saw it still flat black and kinda oily. And read about something about drilling a few holes on the stock pink 66cc air filter box to promote better air flow and possibly make my plug chocolate brown (trying to lean out my setting) .. after drilling a few holes, started my motor and it idled very high & adjusted the idle screw and the motor died. It only starts when I turn on the choke lever then when I turn the choke back off, the motor won't start. Did I messed up the air filter box? I want to start riding again :-||

Here's the air filter box I drilled
IMG_20130731_135757_zpsc3e6ab92.jpg
 
first thing I'd do is put some tape over those holes to see if problem goes away - you might have knocked something else out of whack while working on it
 
It SHOULD run pretty much the same with or without the filter. The stock filter should not restrict air flow that much. (which it sounds like it was doing.) Unless like crassius said and ya knocked something out of whack. Check for intake air leaks and a slipping choke lever. The choke might be slipping down and cutting air flow. And OH YEAH, Make sure the petcock is all the way ON. Hey, It happens more than you would think.
fatdaddy.
P.S. Read yer post a little closer. If it runs with the choke on then yer getting too much air from somewhere. Check for intake air leaks.
 
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Thanks fatdaddy and crassius for the reply.

I did taped the holes and got it to start and run again. But I noticed that choking the motor isn't killing it. It used to kill the motor when I choke it after warm up but after I did the air filter mod, starving the engine of air isn't killing it . I'll try to look for that darn air leak.

ryan
 
I concur with FD... The holes shouldn't have much affect on it.
My guess is that some dirt is clogging the main jet in the carb.

That might explain why it only runs with the choke on?, (because the choke forces it to draw extra fuel from the float bowl). (?)
 
i will check the intake manifold to see if it has air leaks. im suspecting that too much vibe & gas melted the previous silicone rtv i smeared on the carb connection since the rtv i used is only high temp & is not gasoline resistant. thanks for the help guys! :)
 
get that fixed with some proper gasket sealer. keep doing plug reads until you get the color your looking for. Consider you may need a different jet or mixture ratio to get dialed in properly

spark plug color chart
 
meatgrinder said:
i will check the intake manifold to see if it has air leaks. im suspecting that too much vibe & gas melted the previous silicone rtv i smeared on the carb connection since the rtv i used is only high temp & is not gasoline resistant. thanks for the help guys! :)
Click to expand...

A quick, simple intake leak test.
Get a catsup or mustard bottle with a squeeze top. Drizzle water on both fittings, one at a time so you know which end. The engine will either stop or slow if water is getting in. And the little water that gets in won't hurt the engine at all. Cheap, simple, quick and DONE.
fatdaddy.
P.S. Don't let yer lady catch you dumping the catsup down the sink just for the bottle. I'm still catching crap about that one.
 
i use starting fluid to check for leaks, start the engine then spray a little around the intake and base gasket, if the engine revs up then you have a leak
 
Thanks a lot for the help! I did start the bike today and ran it for couple of minutes. I did a comparison run. With the filter box hole not taped, the bike ran fine at first but after several seconds of short burst WOT, the bike bogged down and sounded like it was starving of fuel (maybe?) After the 1st run, I taped the holes and the bike ran great and no bogging down, but when the bike was idling, the rpm is slowly increasing. Really suspect the leak is coming from the carb connection to intake manifold. disassembled the carb and intake manifold and cleaned the crapped out rtv and replaced em with fresh rtv silicone. Still have to wait for tomorrow to see if it works

Fatdaddy- thanks for the ketchup bottle technique. Will do that to check after the rtv has cured since I don't have starting fluid around the shop

Ryan
 
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I'm having the same exact problem with a new speed carb that I just installed. I predrilled the holes for the air filter cover as I have always done. Then I started the bike up and the first run went great the bike ran fast and achieved top end like it should no 4-stroking at all at WOT or down hills. The next run was a different story it started doing exactly what you are talking about. I have an air leak as well I believe :(
 
ok, it's been a week now. what did you find out?

the holes won't make it do that. gotta be an airleak.
 
Turns out I had an air leak on my speed carb. Once that was fixed it ran great! Throttle response isn't what I would truly want so I got a Dellorto clone off eBay. I have just gotten it installed but haven't had a chance to try it yet.
 
As my favorite quote on this website paraphrased 'if it's not broke don't mess with it or it will be'. That one little saying means a lot to me.
 
Ok so after trying the clone carb with little luck (tried various jets), I ended up going back to the NT Speed carb and using a 64 jet. Now I'm getting a good WOT with no to little 4-stroking once warmed up. Note: my intake and exhaust ports have been matched and I have the expansion chamber exhaust (banana pipe) and high compression head from Fred.
 
hi guys..just got a few questions to see if anyone can help me think outside the box here.. i posted on a page bout no fuel/loss of power because my bike(which has over 300 miles) decided it wanted to starting losing acceleration and is now where it starts and a few rounds of pedaling and i can get it to barely idle. yesterday, it would start and idle but still wouldnt go..like its drowning in gas and its fouling every spark plug i put in there..Ok, so i been looking all over it--- I replaces plug wire, petcock, filter, checked the carb(everything seems to be functioning) and new spark plug. still had the bogging, no acceleration issue. took the exhaust pipe off and she sounded alot better but started throttling outta control.. i look down at my cylinder and shes leaking a lil oil from bottom gasket..i changed bottom one out(top was fine), took a glance at my crankshaft seals(dont see anything really without taking it off), gasketed up my carb throat, checked my throttle cable and slide and took her out..same thing is happenin if not worse it seems..i mite b runnin rich a little still but will make up some 40:1 cause right now im still running inbetween 24 1 and 32 1 any ideas or suggestions..? once again thanks everyone for your input and you dont know how much of a lifesaver this page is zpt
 
look along the seam between case halves for seepage, you may need to tighten all case bolts (including the 3 under the clutch)
 
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