Originally Posted by nils
hello hesky, i so your post on the sts site.
i hade contact jp about it and they did not reply to me jet.
i have orderd the new long mainfold from jp to see if this works better.
i had no time to test it jet,i have a club race next weekend then i wil test it,
and i have 4 weeks hollyday now jes,
time plenty to test it.
i wil keep you informt,how it went.
yeah let use know how you get on.
Originally Posted by coldfusion
Hesky/D, i think your guys hit it spot on.
I changed from the JP to my NSR for last weekend's race and had experienced similar probs. So i tuned the NSR back to standarad settings (Cyrul's method) and started from there. The engine was good at idle and top end but had problems with low end just like the JP. So i had suspected the clutch was the root of the problem. Loosen the clutch spring about 0.2mm and t was better but the biggest improvement was when i changed the darn clutch shoe. And presto - the engine came to live and no probs later on.
Now that i have a good clutch going - will try to put the JP back on my car and see how this mother rips!!! will fill you guys in on my quest for 'another happy outing at the track'
Cheers and thanks for all the help guys!!!
yup, you have to bare in mind with these very revy 2 stroke engines they produce there peak power rather high in the rev range, if the clutch engages to early or drags quite a bit you will get a false impression and think the motor is running out of tune. also you can have the same engine in one car and then put it in another and it may feel like a much quicker or slower engine due to the efficiency of the cars transmission, gearing, clutch set-up, weight, the list goes on!
Its easy to forget about the transmission set-up of the car, I try to make sure the car is running as best it can when I start dialling in a new engine.
Glad your getting somewhere now
Originally Posted by coldfusion
Just curious any of you guys run the FX12 5 port with or without the 5.4mm insert that comes with it??
Also, i've ran the engine 25 tanks till today. Should i remove the 0.1mm shim and keep it at factory setting of 0.3mm head shims?
Using the 5.4mm insert will increase the usable range of the carb on your 5 port .12. Simply put it will give you a wider window for getting it in tune, making it easier to get dialled in. but at the cost of low end power, it is still a restrictor.
if you are not running more than 20% nitro shimming it to .3mm should be fine. keep an eye on the temp.