Wot full speed lurching

Ive exhausted myself looking for airleaks with a leak down tester. Sanding heads and cylinders changing a million gaskets, and i still cant seem to find the air leak that causes my E50 to lurch when i go WOT down hill (or very rarely if im on a flat).

Is there anything else i may be missing?

My set up:

E50

Treats teflon reed

Malossi 4 petal cabon reeds

21mm phbg 106 main w7 needle (second richest clip)

Hpi timed around 2.9 btdc (feels safe runs cool)

Hpi pull start

Needle bearing lightened bell

Treats jammer v6

High comp head

Mlm cali sidebleed

Im barely running without four stroking at WOT and it still does it?

Is the bike pushing itself so hard it sucks in too much air?

I know its just mopeds mannnn but idgaf this one has to be perfect! (edited)

Re: Wot full speed lurching

Probably Fred /

Post a video of it doing it

Re: Wot full speed lurching

I will sometime this weekend i need to grab a go pro helmet from a friend or something, but thats prob the only way i canexplain this bs

Re: Wot full speed lurching

Check your chain. Is correct tightness? My H2 surges more with a loose chain. But that is at small throttle openinings.

Re: Wot full speed lurching

Bad Cadillac™ /

Up jet. I think you are running out of fuel especially when going down the hill.

Either that or you are not getting the exhaust out fast enough. (edited)

Re: Wot full speed lurching

what is the compression and piston deck height? single ring piston needed a head that was counter sunk a little more than 1mm to get the squish in check. also could be reed flutter? I really dont like the cali pipe either, switch to an estoril, you will be much happier overall.

Re: Wot full speed lurching

Blaine- The artist formerly known as Plumber Crack "(OFMC)" /

Is this "lurching" more like a "surging", like you would be turning the kill switch on and off and on and off? Could this be a fuel restriction, where it's not quite restricted enough to be an issue most of the time, but with the high fuel demand at WOT, the fuel can't keep up. If you get to WOT and it's good for a few seconds or so before it starts to act up, i'd look for a restriction.

Re: Wot full speed lurching

Brent Bublitz /

Plumber Crack "(OFMC)" Wrote:

-------------------------------------------------------

> Is this "lurching" more like a "surging", like you

> would be turning the kill switch on and off and on

> and off? Could this be a fuel restriction, where

> it's not quite restricted enough to be an issue

> most of the time, but with the high fuel demand at

> WOT, the fuel can't keep up. If you get to WOT and

> it's good for a few seconds or so before it starts

> to act up, i'd look for a restriction.

Fuel starvation would be my guess as well. Had that a few times. Had to go up to a larger fuel line on two bikes. Some Petcocks just can't keep up with a certain size kit.

Re: Wot full speed lurching

I personally think it could be rich condition causing that. When you get on a flat or downhill the revs come up I bet, and you start pulling fuel harder through the jet. You said it's almost four stroking. ..that's rich

But it could be a lean condition as well.....maybe lugging causing that four stroking and then going lean when into the power.

Re: Wot full speed lurching

Probably Fred /

Try rich atomizer #264 but around 100-102 main jet, (I use #101 main and 40 idle jet) but with estroil pipe) 38-42 idle jet, 30-40# slide and neutral/middle clip selection. The 264 will get you a leaner clip position and will lower main jet so give it a try.

When a PHPG carburetor is tune you'll have a bit of four stroke when you back off from full throttle. As for the 40 or 30# slide I got bikes that the # 40 works good but then some the #30 slide works good

But don't use a # 50 slide.

That slide for me was too lean for Reed kits/works better with piston port kits

Re: Wot full speed lurching

try with the fuel tap on reserve position

Re: Wot full speed lurching

The timing of how long it goes between "surges" would tell a lot

Re: Wot full speed lurching

Blaine- The artist formerly known as Plumber Crack "(OFMC)" /

We'll probably never know now.

Re: Wot full speed lurching

fuel starvation

Re: Wot full speed lurching

drill a 1/8 hole in the middle of the Puch crest in you gas cap to vent it better

I have had a few puchs do this on high rpm

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account