Scooterotica

Engine spluttering about 1/2 throttle in all gears - fine on the stand, nice & crisp, no splutter.

GP200 engine (Indian from MB) no fancy stuff - Stage 4 ???
MB BGM BigBox Clubman exhaust
25mm PHBL Dellorto
102 main jet
50 idle
AQ264 atomiser
D26 needle (2nd clip from top)
40 slide
60 starter jet
2.5 needle valve
Air mix screw 1 1/4 turns out
Running through air box (Serveta type in tool box with air filter in)
All above is as recommended by MB

Other info -
Tried running without airbox (open mouthed, panels off) no different
Tried several plugs (NGK B8ES) all set correctly - no different
tried clip on needle at top slot - no better
tried clip at 3rd from top & slightly worse (spluttering just before 1/2 throttle)
Carb sits slightly at an angle - centre line as you look at it is in the 1 o'clock-7 o'clock position - like this / due to the fuel chamber being too big to fit it perpendicular

Put my old SH22 carb from the 150 I took out on it & it's fine (did this to rule out any timing issues or anything else) - I have no idea how the SH22 is jetted btw
From what I've read the atomiser and needle kick in at 1/2 throttle, so I think this is were I should be looking but which way ???
Mate of mine has suggested checking if the choke is fully seating off when it's off ???

I would appreciate any thoughts on this before I go & spend my life savings on different jets - anybody who gets it right first time wins a prize
ServetaDave
registered user

Posts: 9
Joined: Sat Jan 04, 2014 12:27 am

Leave the SH22 on?

try x7 or x13 needle

FREAK wrote:try x7 or x13 needle

you could do but then using a phbH needle in a phbL carb would likely not be a good solution???

It does sound like needle position given the throttle position, drop the needle to the next clip it nearest the top and try again, if you run out of clip positions you need the next weakest needle and start at the richest setting, try again, if still not right, move clip again ad nauseum until its right and plug chops are satisfactory.

I had that set up and it ran fine tbh,

At WOT is it still spluttering?
if not your main jet is OK and donnie is right your needle is obviously too rich at 1/2 throttle just change it for a weaker one (bigger diam, tapered part shorter...)

I think D22 is the next leanest needle for the PHBL. Difference between the D26 and D22 is that the tapered length is 2mm shorter on the D22 hence leaner on the progression.

i ran a 200 set up , using a rs clubman, i used AQ262 Atomizer with D22 needle 2 from the top. ended up on a 98 main jet. Airbox was drilled and the inner " neck " was cut out to get more air in. this was recommended by Mb .
always worth checking that your choke is working correctly.

where about`s are you ? if localish, you could borrow my atomizers, needles/ Main jets.

MB have recommended D22 2nd from top & 92-95 main. Thanks YAMLAM I have everything I need at the moment, am in Glasgow btw. Will post how I get on once tried out, but this weekend I will be mostly incoherent in a field in Kelso :-/ hic