Scooterotica

Not on your setup. I’d just go with the tried n tested 30mm PHBH

what feels like a carb issue could be something thats not

Muppet wrote: ↑Sun Apr 15, 2018 9:11 pm what feels like a carb issue could be something thats not

Yes im thinking this, but what i wonder?

All booked in with Mark Broadhurst on Friday to get it sorted once and for all. Mark seems to think there’s a fuel starvation issue somewhere from what ive told him so we will see.

Update on this: went to MB he checked fuel flow from tank, from carb, from fuel valve etc seemed fine. He checked the timing with a strobe which was bang on. One thing he did comment on was my choice of 25:1 or 4% fuel oil mix, said it was very viscous which I would have to agree with him on so will now change to 32:1 or 3%.

Ran it up on his dyno with something like a 145 main jet in ran clean which was a bit strange so he took the filter off and reduced the main jet to a 138 this time it spluttered when it went onto the main, so after all that it was the bloody filter making it run lean, i only really fitted it to stop the spit back from the carb which is horrendous despite being a reed valve motor, he seems to think the executive spit back stems from the pilot jet which is a 58 so I’ll be experimenting with smaller pilot jets.

If anyone has any other ideas on combatting the spit back fire away. I had considered it was because the cylinder has been turned but i dont really know and in any case its only a touring tune rather than a full race tune.

You’ve been for a dyno, and you still have to experiment with pilot jets?

Did Mark not set the whole carb up?

drunkmunkey6969 wrote: ↑Wed Apr 25, 2018 8:28 am You’ve been for a dyno, and you still have to experiment with pilot jets?

Did Mark not set the whole carb up?

in all honesty i dont know why but no he didn’t, the last dyno i had i dropped a load of money on it and came away with a scooter that ran like a bag of shite and ended up setting it up myself. Harry Barlow told me one time “you cant set a scooter up on a dyno” guess he’s right.

Can't speak for others but my approach has always been:

Scooter in, I dyno test, if results are OK, I inform the customer, they then have peace of mind, pay and leave.

If results of dyno show problems, I inform the customer, and make suggestions as to what I think the problem might be (jetting and/or mechanical).

If approved, I then proceed to investigate further and remedy the situation - the goal being to provide the customer with information, options, and hopefully..a more complete/mechanically sound scooter than they arrived with.

If it was just a jetting problem, I'd reset the whole carb to whatever jetting the situation commanded. If for whatever reason I couldn't complete the job 'in full', then I'd be reluctant to start it in the first place...unless there was a very good reason to do so or some sort of agreement with the customer - but that would be made clear at the time.

On the rare occasion a customer goes away, and at the time everyone is happy, but later something is found to be 'not 100% spot on' - then the best thing the customer can do, is come back and talk to me about it - I don't think I've ever turned anyone away or refused to look at the situation again.

I'd have to disagree with Harry on his statement, but I'm bound to...i own a dyno.

Hope you get your problem sorted.

Yes not knocking Mark at all just severely pissed off that im going round in circles with this f@@king thing.

So in essence ive got an 85 mph scooter that cant be ridden over 57 mph otherwise it overheats and sprays oil and fuel out everywhere.

Ride at 57 and its fine, ride at 60 and the temps sky rocket.

Has the spitback mess improved with the move to 3%? just wondering as 4% is recommended for the GT240 kit and the oil from the spitback is really messy and with the rebored cylinder, I have gone down to 3% and it seems a little less messy.

Re you dyno results and inconsistent responses to jet changes, have you considered the possibility of an air leak or maybe damaged petals?