imola set up questions

[jaelee]

i finally got my imola series 3 running. i have the timing set at 18 BTDC, i'm running a 30mm oko carb jetted at 40 pilot, 142 main, and a jjh needle on the second clip from the top with a scootrs exhaust. the ignition is a 120w bgm stator with an af rayspped light flywheel ( i think the new onw ) plug color is fine and in general i'm pretty happy with the set up but i'm running into a few issues:

1. when i open up the throttle it kinda sputters and breaks up a bit, i've read the problem might be due to the inlet into the bowl is too small and it's fuel starved

2. when i let off the throttle it keeps popping, is this normal for a lammy?

any help or suggestions are welcome

thanks

[storkfoot]

In answer to your 2nd question, yes, that is the case even on a reed valve.

If you're "spluttering" this may mean you're too rich at a particular point in your throttle progression but it is hard to diagnose these problems from what somebody describes in writing.

Maybe mark your throttle 1/8, 1/4, 1/2, 3/4 of throttle opening and then rev it on the stand. Make a note of where it splutters and also look at whether your exhaust goes smokey at that point. That may give you a heads up as to whether it is carb related and, if so, whether it's your needle clip that needs moving.

Have you done a plug chop, or choke test, on full throttle? Gut feel tells me your main jet may be too big. I think I had a 118 on a 28PWK on a Mugello 186 with PM expansion.

The other issue that you may have is your flywheel. Have a read of this thread:

http://scooterotica.org/forum/viewtopic ... 8&start=30

[dapper]

Firstly, I'd agree with Storkfoot, that your main sounds too big. Here's a link to the mods/checks in case your OKO needs fettling.

http://www.miniriders.com/tech-talk/268 ... -mods.html

Item 2 is deffo worth doing if its not already done. to allow more fuel into the fuel bowl and to stop fuel starvation. Soldering off the stop in the bottom of the fuel bowl is also worthwhile. Checking that there isn't anything partially blocking the tiny pilot hole next to the main jet also worthwhile. Get a can of compressed air (air duster) to blow through all orifices

Here's a link to the ScootRS site which shows a list of other people's carb settings, which may give you a lead to where you may need to set your carb up, but plug chops are the right way to go, even then. There's only one specific for an Imola, but I'd be surprised if a 142 main jet wasn't too big for anything but a 200-225 TS1.

http://scootrs.com/tech.cfm?tip=jetpwk

You don't say at which point in opening the throttle you get the spluttering/breaking up?? Does it clear up after this point? A bit more detail would help.

[jaelee]

i think it's the jetting....i just took it out for a ride and when in the upper rpms around 6-7 k it sounds like it's farting. i originally thought it was the ignition set up due to all the talk here about the bgm stators paired with the af rayspeed rotor. i guess i over thought it

[jaelee]

ok i think i have jetted properly i have 35 pilot, jjh needle on the second clip from the bottom, and a 135 main. throttle is crisp at 1/4 1/2 3/4 and full. however....at about 6-7 k rpm it feels like it's running out of gas and kinda gets lurchy if that makes sense. Is this a stator problem or a fuel into the bowl problem? can anyone confirm?

[storkfoot]

This sounds like the problem I had with my AF light flywheel but I'd be hesitant to diagnose it as that from what you've said so far.

Flywheel_ When my TS1 got to a certain revs (6100 in my case) it would judder like it was just about to run out of fuel. You could ride through it but it still didn't run particularly well beyond this. When this first happened to me I thought fuel starvation caused by the routing of the petrol pipe on the TS1, or a blocked petrol cap. It was neither and it was putting it on dyno that diagnosed the problem as the flywheel.

Carb_ what have you done to check that your jetting is right, particularly on the needle and main? What air filter, if at all, have you got on the carb? As already mentioned, this may well be the float chamber running out of petrol too (common issue with some copy PWKs).

Timing_ how do you know it is set at 18 degrees and is this 18 degrees static, or by strobe at revs?

If I was you, if you have done plug chops and/or choke tests and you're as sure as you can be that your carb is set right, and your timing set ok, I'd (i) borrow a known working Indian electronic flywheel, and if that doesn't sort it, (ii) look at whether the inlet valve into your float chamber is big enough to flow the petrol when you're at speed and, therefore, using more petrol than the carb can cope with.

Good luck

[lammysilver]

**Storkfoot (or anyone else reading who can help..),

Just rode back form Woolacombe to London, got the same spluttering issue in the last 3rd of the throttle particularly at its highest rev point it worsened.
The scoot starts fine and revs from pulling off, hits a sweet spot and accelerates real nice through to about 2/3s then at highest revs it judders, i initially thought fuel starvation and re-routed the fuel line, cleaned carb/jets, and filters... but it was still there and caused some major probs on the motorway, namely being halfway past overtaking cars and it failing to accelerate so id roll off the throttle and it would pick up again!? stressful!!

Imola with ancilotti, 28del, 70, 264, 55 pilot, 122 main.

Im guessing its the problem you described as 'flywheel', by this do you mean stator/timing? if not could you please explain and ill crack on fixing it asap.

Thanks

[storkfoot]

The original poster had an AF light flywheel, like me. My flywheel was incompatible with my stator. As soon as I replaced the flywheel with a lightened Elemec Indian one, my problem went away.

The flywheel went back to AF for testing. I believe it's now running well on Ben's own bike. I got a credit note.

[lammysilver]

cheers for that, after a bit of research im pretty sure its '4-stroking' in the last 1/4 of the throttle.

Ill try a smaller main jet and see how i get on.