4 stroking after 200 yds

[Martin s]

Hi I have new build RT 225 piston port kit with 30mm phbh and clubman.
After about 200 yds or so the bogging starts and gets really bad.
I have to stop and keep reving it but it eventually cuts out.
Played with jetting and lowered main jet but still the same.
AV266, 40 slide, X7 second notch down, 300 float valve, 55 pilot, 123 main jet at moment.
Running with MB tea strainer, but does it without.
Checked choke plunger.
Checked cap breather.
Managed to get back on about quarter throttle.
Will start then when you hold throttle open and then revs cleanly on stand.
17 degrees with uni stator. Rear exit fast flow OMG.
Wondering if stator or fuel flow although not done a flow check yet.
Would fuel flow cause the 4 stroking?
Cheers Martin.

[Rich Oswald]

Really does sound like the choke but you have checked as you say. Are you sure it is not lifting due to a tight cable when you are sat on the scooter?

Rich'

[MickYork]

What colour is the plug ?

Stator is a good call, would give similar symptoms.......changing it for a known good one is the best test.

[ULC Soulagent]

I’d say carb issue, check ur choke ain’t sticking like Rich said. Also check that all ur jets are tightly secured in their respective locations

[Hat]

Really does sound like the choke but you have checked as you say. Are you sure it is not lifting due to a tight cable when you are sat on the scooter?

Rich'

Good test for this - if it revs clean on the stand, sit on it off the stand & rev it to see if you get the same response. It could be stator/ cdi breakdown as it comes under load. If you’ve tried altering the carb settings then try working back from plug - ht lead - cdi - stator, replacing each in turn

[Fast n Furious]

It does sound like it has developed the dreaded stator made rev limiter!

[Hat]

It does sound like it has developed the dreaded stator made rev limiter!

i had this exact issue & a swap out of the CDI for an Anthony Tambs unit fixed it immediately

[ROClarke]

Head Gasket ?

[ULC Soulagent]

Head Gasket ?

Depends on what crank/rod he’s using will define if he uses a head gasket or not

[martyn dwane]

i thought if it reved out on the stand ,then it`s a jetting issue , if it wont rev out on the stand then electrical...... but then theres always exceptions

[dscscotty]

Have you gapped the plug?, had an issue like this last year, it'd been round the doors to his mates etc, new stator fitted etc, but to no avail, I checked plug gap, which was to big, re-set it and cured and still fine now, fella couldnt believe it, sometimes we assume the worst and its the simplest of things, Good Luck!

[St George]

Mine revs out on the stand fine, dies on load. Carb triple checked ?

[MickYork]

Mine revs out on the stand fine, dies on load. Carb triple checked ?

stator ........

[a.lo]

how old is the exhaust? I ask because I had a problem with my scoot when first rebuilt that would start and rev and run for 100/200 yards then choke and die. turned out the only old part I put back on was totally coked up (80,s Mickek)

[Martin s]

Thanks for the excellent replies, only just been able to work on it. Swapped the usual stator, cdi, reg and spark plug.It's obviously jetting.
Changed the atomiser to av 264 with the same x7 but is only rideable with clip in top position. Done a few miles, now intermittent cutout with no spark, then starts again. Hoping to get a casa ignition at the weekend, had enough of
the indians now. Does it need to be run in to put it on a dyno? Not done any plug chops yet, but not confident on the
jetting. Hoping to get to Dorset on it next week!

[Warkton Tornado No.1]

Thanks for the excellent replies, only just been able to work on it. Swapped the usual stator, cdi, reg and spark plug.It's obviously jetting.
Changed the atomiser to av 264 with the same x7 but is only rideable with clip in top position. Done a few miles, now intermittent cutout with no spark, then starts again. Hoping to get a casa ignition at the weekend, had enough of
the indians now. Does it need to be run in to put it on a dyno? Not done any plug chops yet, but not confident on the
jetting. Hoping to get to Dorset on it next week!

You are probably correct about the ignition, but I would be cautious about the atomiser until you can get that sorted!

Whilst I believe that the smallest atomiser possible is going to give much better chances to fine tune the carburettor, I would stick the AV266 back in for now as it will be safer.

Get your ignition sorted, then you can sort the fuelling. Beware of copying what others have as most engines are unique, to an extent, & an awful lot of set-ups have too far retarded ignition & run too rich carburation, which means an engine can seem lethargic.

Good Luck sorting it!

[Martin s]

Cheers Warkton, it won't run with the 266 in. It would only stop bogging down with the 264 in. I've tried all the clip positions and top clip actually makes it rideable. I guess every engine's different. Will be plug chops after I get the new ignition. Thanks for your advice.

[rossclark]

I have piston ported RT in my Lince it was very boggy on AV266 with a lot of messing I ended up on AV264 / X7 second clip down I found it rich across the range still dropping main down to 118 MJ. I was running the BGM filter / hose on a PHBH30 with the BGM v4 clubman.

I've just rebuilt it all so will see what it's like when the weather improves.

[ULC Soulagent]

This was my setup albeit with a 28 delly, tea filter and Bgm mk1 clubman
As WTNo1 said no two engines are identical on carb setup, I’d put a few miles on the new kit b4 taking it too the dyno man( don’t go chasing Bhp as they’ll lean it right of to achieve that) anyway : Pilot 48
Choke 70
Pilot 48
Main 118
Needle X7 top clip
Atomiser AV264
Slide 50
Float 3.5g

[Martin s]

Thankyou. I've got a casa performance blue filter I'd like to shove on, so will be trying that with a smaller main.