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View Full Version : 310 motor 1st start and it revs to the moon!



JasonB
04-28-2012, 10:08 AM
Just built a 310 motor, pump gas dome, new 39 pwk (190 main jet, 52pilot) , in frame drag pipe, v force reeds (new) gas mixed 32/1 with techniplate. Br9es NGk plug at 25 thousands.

Kicked it over for the first time and it reved to the moon. So I checked everything again and retried and it did the same thing! Cable is loose. Slide is free to sit where ever. I do not have the slide stop screw screwed in at all past where it came out of the box. Air screw is 1 1/2 turns out. Stock pwk needle 3rd clip. Jetsrus.com still owes me a dgh needle that shouldbbebhere any day. Anodized head pipe flange.

What am I missing! Base studs and head studs are torqued solid. Intake tight around carb too so no leak there. Wtf?!

Toledo_Tommy
04-28-2012, 10:11 AM
Did you check the floats in the carb ? Maybe it's not getting enough gas , 2 strokes rev up high when they are running out of fuel.

Xowner
04-28-2012, 10:21 AM
Jason you have an air leak almost certain. You need to do a leak down test on a fresh motor to make sure its sealed well. Text me if you got some questions....

Mosh
04-28-2012, 10:25 AM
Did you actually look to see if the slide is closed? It happens..Ask Kintore..LOL

You may want to tap on the bowl in case the float is stuck down not letting fuel in, That will usually loosen the needle from the seat by tapping on it.

johnny's X
04-28-2012, 11:35 AM
I am with xowner...airleak

pantera1975
04-28-2012, 01:19 PM
Did you actually look to see if the slide is closed? It happens..Ask Kintore..LOL

You may want to tap on the bowl in case the float is stuck down not letting fuel in, That will usually loosen the needle from the seat by tapping on it.

Ive had this happen!:wondering

bkm
04-28-2012, 01:22 PM
Jason, I'm with Mosh on this one. Did you ever get the PWK specific cable? It doesn't take much of an opening to rev them to the moon.

JasonB
04-28-2012, 05:07 PM
Thanks for all the feedback guys! How big of an opening is there supposed to be at the slide? I may just need to make sure the throttle cable is adjusted right; I was only making sure it wasn't hung up! And I do have the right cable, I also have the part number of anyone else needs to order one for a pwk :) I will pressure test the motor after I mess with the adjustment on the throttle cable. Thanks again guys!

torque
04-28-2012, 05:39 PM
i had this happen on one of my bikes, while adjusting the needle. move the clip install the slide and fuel tank kick it over and straight to 9000 rpm. removed the tank check the slide every thing seemed good kicked it over with no tank ran great. installed the tank kicked it over and right to the rev limit. wtf. turns out the tank pulled on the throtle that was not in the right spot.

lightemup01
04-28-2012, 07:02 PM
go over everything 4 times

JasonB
04-28-2012, 11:13 PM
ok i played around some more; the cable had the slide pulled up a little bit. I think it was enough to make a difference. going to start it again tomorrow and see what happens!

ATC-Eric
04-29-2012, 01:15 PM
So, what did you find?

JasonB
04-29-2012, 07:58 PM
The slide was still up a little bit; screwed it into the thumb throttle all the way and the slide dropped fully! Bike started and idled perfect first kick! Three heat cycles down now just chasing ignition break up top past 3/4 throttle while moving.

RIDE-RED 250r
04-29-2012, 08:00 PM
OEM or aftermarket CDI??

bkm
04-29-2012, 08:04 PM
The slide was still up a little bit; screwed it into the thumb throttle all the way and the slide dropped fully! Bike started and idled perfect first kick! Three heat cycles down now just chasing ignition break up top past 3/4 throttle while moving.Close the gap up on the plug. I think mine is at .018

JasonB
04-29-2012, 08:54 PM
You think the plug gap will make it cut out at high rpms's? Same thing it was doing before I replaced the carb, pipe, cylinder, reeds, and gas.

JasonB
04-29-2012, 08:55 PM
OEM or aftermarket CDI??

OEM. everything is stock. And old.

bkm
04-29-2012, 08:57 PM
That I don't know. When I installed my BB kit back in the day it would break up past 3/4 throttle. I closed the gap and problem solved.

Mosh
04-29-2012, 08:59 PM
What carb and jetting are you at? What air filter? lid no lid? What is your break in mix at?

EDIT sorry. re read your first post.
Try going down to a 48 pilot and 182-185 main, needle in the middle. Then plug chop it if it runs good.

Also now make sure your slide is opening all the way too before playing with jetting.

RIDE-RED 250r
04-29-2012, 09:04 PM
OEM. everything is stock. And old.

Alot of people with bog bores, myself included, have had some issues with non-OEM CDI units. Breaking up at WOT, kickback when starting (especially on hot/warm re-starts) are the main 2 issues.

If you end up narrowing down to an ignition problem and wish to replace the CDI, I would highly recommend sticking with OEM.

JasonB
04-30-2012, 10:51 AM
Rob; I was planning to step down to a 50 pilot and smaller main jets, I just want to make sure im breaking ti in with enough fuel. Is it really ok to start going down jet sizes and tunning before the motor has had a few tanks of gas through it?

BKM; i will re gap and see if that helps. I also need to order a new plug cap. my stock one is the hard plastic version and just doesnt fit over the plug in a way i feel good about either. Theres alot less room in the cradle around that motor lol
\

Ride-Red; i will def be sticking with OEM if the CDI needs replaceD!

bkm
04-30-2012, 10:59 AM
Your pipe is going to be the biggest factor in jetting. On my 310, pt hi-rev, 39pwk. I run a 50 pilot and 175 main, needle in the middle clip.

Mosh
04-30-2012, 12:08 PM
You dont have to over jet rich for break-in...Just mix your oil rich. usually one tank is plenty at like 20-1

NOS_350X
04-30-2012, 10:20 PM
High rpm stutter is usually a stator.