GasGas 300 Keihin PWK 28mm.

[fourex]

As above, my '14 model came standard with a JJH needle which I have always felt was a little lean coming into the mid-range. I'm just curious if GG has changed this needle as std between then and now ? If so what is it please.

[baldilocks]

Number 3 slide cures it.

[peterb]

For the 300 only, I have always used a GJH needle, slightly richer from pilot to mid range than the JJH. If you can't get one in Oz, Allens in the UK have them. Bye, Peter B.

[fourex]

49 minutes ago, baldilocks said:

Number 3 slide cures it.

Not completely in my opinion, I've been running the # 3 slide and a 48 PJ since mid 2015 and it's better than the std 3.5 and 45, but it could still be better imo. I think a change of needle is the key to what I'm looking for, but I'm not confident on which way to go.

Thanks peterb, I'll look into a GJH, is that with the std # 3.5 slide ?

[peterb]

Yes, a GJH with a standard slide works well, a bit more controllable at lower rpm's and it prevents the pinging/knocking with the std set up. Bye, Peter B.

[fourex]

peterb, are you sure it's a GJH that you recommend. The reason being, I've looked up the Keihin chart for these needles and the GJH is actually leaner from 1/4 to 3/4 throttle due to the taper compared to the JJH. Cheers.

[peterb]

Hi fourex, I ran my laptop through a restart which then disabled my TC account and have only now got back in through the signing in after a TC password reset. Yes, I am very sure the needle is a GJH, used on various GG 321 and Pro 300 from 1999 till 2010, with a 128 main and 35 pilot. Needle clip second off the bottom. I agree, the Keihin table indicates the G to be leaner than the J from 1/4 to 3/4 but, the taper of the G is 2 deg 26 mins vs 3 deg for the J, you can see the difference when you hold the two together, which allows more fuel to pass with the G, the fuelling  feels richer. The std J would always knock under load, the GJH cured this and provided a more controllable response at low revs. Hope this helps, bye, Peter B.

[nigel dabster]

Lift it up on clip.

All GGUK use jjh.

45 pilot is better?

3,0 is best.

have you set float height?

Edited May 9, 2018 by nigel dabster

[faussy]

6 hours ago, nigel dabster said:

All GGUK use jjh.

That doesnt mean its right. Hearing one of their bikes recently, i didnt realise there was a fuel embargo

Edited May 9, 2018 by faussy

[sherpa325]

JJG and JJF are richer in the bottom rev range - F being richer than G

Cheers Greg

[faussy]

8 hours ago, peterb said:

 the taper of the G is 2 deg 26 mins vs 3 deg for the J, you can see the difference when you hold the two together, which allows more fuel to pass with the G, the fuelling  feels richer. 

A shallower taper from the same diameter surely means weaker....

Edited May 9, 2018 by faussy

[nigel dabster]

18 hours ago, faussy said:

That doesnt mean its right. Hearing one of their bikes recently, i didnt realise there was a fuel embargo

Of course it doesnt but do you know more than Kev Hipwell and others? My settings are taken from advice from an ace mechanic/tuner (7world champs) and practical experience of a change from 3.5 to 3 which on a 250 is more crucial, not sure why but is.

[nigel dabster]

On 07/05/2018 at 11:26 AM, fourex said:

Not completely in my opinion, I've been running the # 3 slide and a 48 PJ since mid 2015 and it's better than the std 3.5 and 45, but it could still be better imo. I think a change of needle is the key to what I'm looking for, but I'm not confident on which way to go.

Thanks peterb, I'll look into a GJH, is that with the std # 3.5 slide ?

use a 3

[fourex]

I've ordered three different needles, I'm going to experiment.

[faussy]

8 hours ago, nigel dabster said:

Of course it doesnt but do you know more than Kev Hipwell and others? My settings are taken from advice from an ace mechanic/tuner (7world champs) and practical experience of a change from 3.5 to 3 which on a 250 is more crucial, not sure why but is.

You can mention all the names you like, or how many world champs the guy has. All i know is that every time i hear jack price riding a section his bike is knocking. Go watch the BTC video from hookwoods if you like, it was particularly bad there. Fast forward to 37:50, if that isnt a bike underjetted, i dont know what is. Its so bad you could possibly say its overheating or there was water in the carb, but that isnt the only section let alone the only trial ive heard it do that

 

 

Edited May 10, 2018 by faussy