Inlet timing too much?

[nelson pk]

Hi everyone.
Been trying to help a mate of mine with jetting and no matter what we do as far a jets/atomisers and needles go, the bike has a flooding issue at low revs. For example when you give it a quick rev, say up to half throttle, it spits back a hell of a lot of fuel and dies.
He has a dellorto phbh 30mm and the floats are set to 24mm as per dellortos recommendations.
The float needle valve is not sticking and is new. I intend to try and lower the floats a little to try and lean the whole system off but i do know that the inlet port timing is 160 degrees.
So my long winded question is........will an inlet port timing of 160 degrees cause very poor running and flooding at low revs?
I know too much inlet timing will cause this effect but is 160 degrees too much?
Thanks in advance
Pete

[sean brady scooters]

your inlet timing of 160 degrees is not the cause of your probs ...however just check firstly that your piston is in the right way up and also that the inlet port has not been altered /widened so much on the near side that the piston skirt does not seal it...

[coaster]

160 is long but not excessively so, I have a 225 barrel with 175 inlet timing that was happy to pootle around at less than 40 mph in top. It was very peaky though and did spit back a bit of fuel but all tuend engines will to some extent unless you use a reed valve. What are the other timings and to spec of the engine?

[nelson pk]

Thanks for the input guys.
The set up is a muggy 225 which has had a bit of work done to move the transfers up to 119-120 degrees and if my memory serves me right the exhaust port is about 175 - 180 degrees (it was a long time ago since it was put together).
The ports themselves were not reworked but i believe the barrell and head was adjusted so it could be jacked up by about 1mm as the transfers were about 112 - 114 degrees and it had compression issues (too high).
Compression is fine now and i think my measurements on the port timings were ok. I'm not a super whizz on port timings i'll admit though.
The exhaust is a jl3 and carb is a dellorto 30mm.
I pretty sure i wouldn't have put the piston in upside down but stranger things have happened!!
Has anyone ever had to adjust float heights differently to the delly recommendations or are the delly settings gospel?

[soosh]

What size is the float needle valve?

[byron]

Has anyone ever had to adjust float heights differently to the delly recommendations or are the delly settings gospel?

I have been playing with my float height recently... how much does the angle the carb sits at need to be taken into account ? are the "factory" settings assuming the carb is pretty much horizontal ? where is the fuel level supposed to sit in relation to say the atomiser ??

[nelson pk]

Hi
Float needle valve is a 300. I've always been led to believe that bigger is better there but i must admit i've wondered if a needle valve too big can cause flooding issues.

[nelson pk]

What i've read from the dellorto manual on phbh carbs is that the carb can be sitting straight or at up to a 45 degree angle with those float recommendations however in one dellorto manual i've got that covers most carb models it does say that "the float should be considered a calibration element and that if a lighter or heavier float is not available the tang can be bent to adjust the level in the bowl but do not go too low as the jets may suck in air when the bike takes evasive manouveurs" or words to that effect.
So in one way that answers my question but i was wandering if other riders out there have needed to adjust the float level or does everyone just go by the factory specs?

[soosh]

Big can be better,i run a 300 in mine and have run a 350 in my 185 but a mate had some flooding issues on his a few weeks ago and went back to 250 and it sorted it out.I adjusted my height to the max but used a solid mount dellorto so it was important to do so but as long as its shuts off before it hits the body,it should be ok.Just try the needle valve,stick the original one back in just to see what happens.Is it a solid or rubber mount?

[nelson pk]

Its a rubber mounted carb. I'll try going back to the 250 needle valve and see if that makes a difference.