Hi does anyone have any experience of selling up dellorto phbh30s on a 500 with either a 2+2 or L5 camshaft, I'm running K&N filters with a replica RMS exhaust, currently running standard carbs with 140 main jets
Thanks sprog
Phbh 30 jetting
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morini_tom
- Posts: 1003
- Joined: 05 May 2006 13:47
- Location: Northampton
Re: Phbh 30 jetting
I have PHBH30 on my 501 engined dart which won’t be directly comparable with your engine or intake/exhaust but maybe the below will help anyway:
No airbox due to packaging issues in the dart frame. Just k&N filters on the carb. I don’t recommend this, it’s just how mine is.
2 into 2 exhaust loosely copied from an Excalibur but packaging again forced some non-ideal lengths and particularly long secondary lengths to package the undersat silencers.
Ported cylinder heads (which needed an increase in main jet size compared to the non ported head)
When I had a 2+2 fitted jetting was as follows:
Slide 40 (I’d like to try a 50)
Needle X18 in second clip (previously I had x1 needle but the rich issue at low throttle openings was much worse on those)
Needle jet 150 (I went down in size as I run a fuel pump and the 200s seemed to let it flood)
Pilot jet 36 (much smaller than standard- it needed this to help cure the off idle rich running. 50 slides might be an improvement further still)
main 130
Atomiser 262T but I know it had some extra holes drilled in it by Alex at NLM when I first struggled with setup. I’m not sure where the holes were drilled so can’t say if the was to enrich or enlean at any particular point.
Hope the above helps. It took me years of experimenting to get mine running perfectly. Initially I had much bigger main jets- 140 or 150 I think and this was definitely too much.
No airbox due to packaging issues in the dart frame. Just k&N filters on the carb. I don’t recommend this, it’s just how mine is.
2 into 2 exhaust loosely copied from an Excalibur but packaging again forced some non-ideal lengths and particularly long secondary lengths to package the undersat silencers.
Ported cylinder heads (which needed an increase in main jet size compared to the non ported head)
When I had a 2+2 fitted jetting was as follows:
Slide 40 (I’d like to try a 50)
Needle X18 in second clip (previously I had x1 needle but the rich issue at low throttle openings was much worse on those)
Needle jet 150 (I went down in size as I run a fuel pump and the 200s seemed to let it flood)
Pilot jet 36 (much smaller than standard- it needed this to help cure the off idle rich running. 50 slides might be an improvement further still)
main 130
Atomiser 262T but I know it had some extra holes drilled in it by Alex at NLM when I first struggled with setup. I’m not sure where the holes were drilled so can’t say if the was to enrich or enlean at any particular point.
Hope the above helps. It took me years of experimenting to get mine running perfectly. Initially I had much bigger main jets- 140 or 150 I think and this was definitely too much.
Re: Phbh 30 jetting
Thanks Tom that's great info, I'll try 50 slides and 264t tubes and see how that works they already have x18 needles and 40 idle jets , but will have to wait for better weather and a track day to give it a proper test