Hey,

Simple question. At the moment my bike is completely stock appart from the wire splice. I'm soon going to be running pod filters and so it will need rejetting. I am going to buy a JHA Jet kit and probably running the blank PJs because tuning will be hard enough for me as it is. What I would like to know is if I will have to buy additional jets or if the ones provided in the kit should be enough. I will be using regular unleaded as usual and still have the oil pump.

I will then (later) be getting some tyga pipes.

Could someone please let me know if I will need additional smaller jets, firstly with the pods only and then with the pods and the pipes?

I did a search but couldn't find the info.

Cheers.

They'll probably be way too big - they are designed for a bike with most of the mods, running on premix. Is anyone here running 180+ still with an oil pump?

There are a few threads abotu it, but I think the search function needs some work before we can expect people to find them easily.

I thought it was just me. When I use the search function it always comes up with so much rubbish that has nothing to do with what I searched for. I tried searching something and selected "search in classifieds", and all the search results are from the discussion section. Something is not right there.


I have heard people say that jet kits are useless for most road bikes, and then other people talk as if you practically need one. I just ordered it today so it's on it's way, I just hope I won't have to buy more jets.

NickoPen wrote:They'll probably be way too big - they are designed for a bike with most of the mods, running on premix. Is anyone here running 180+ still with an oil pump?

Me. And I siezed it on those sizes too when it was 12 degrees or so at Croft...
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NickoPen wrote:They'll probably be way too big - they are designed for a bike with most of the mods, running on premix. Is anyone here running 180+ still with an oil pump?.

Both kits ('21 and '28 ) run 170 to 200 which makes the '28 kit fractionally better suited to normal mods than the '21 as the '28 carbs tend to be up at least 3 sizes up for a similar setup.

If you work out the jet area size if you blank the powerjets on a totally standard '21 you should start at 170/172 (actually 173 really) on the mains. Obviously you cant' go down from this but then again this is for a 45 bhp setup.

Anyway I siezed my '28 on 188-190 at 3*c running no mods other than the airbox, pipes and HRC card.

It's currently running pipes, airbox mod, HRC head, carbon reeds, HRC rectifiers, 182/188, middle of the B needle and its not far off at that.
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Cheers guys.

Looks like it might be alright then

wow. maybe I'm doing something wrong then? I currently have 138/140 running premix on my mc18, although I haven't run it hard yet - that's how it was when I bought it. Powerjets are still in and its a cold day if the maximum is below 22 degreees C though.

NickoPen wrote:wow. maybe I'm doing something wrong then? I currently have 138/140 running premix on my mc18, although I haven't run it hard yet - that's how it was when I bought it. Powerjets are still in and its a cold day if the maximum is below 22 degreees C though.

If your running an open air box and pipes you know it pretty quick once you open 'er up. If your as lean as we think you are it will lock up in about 5 seconds. It is possible your jets were drilled though. Its better to start rich and work your way down. How are your lugs looking?
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Box is standard, filter is still in, pipes look stock, although otherwise it seems pretty race-prepped (all non-essentials removed, full glass, premix, non mc18 heads on it + who knows what else).

I've only really been able to ride it around the block a few times (and it runs hard - power wheelies in 2nd no probs) as the rest of the time I've been working on it and it currently has no brakes, so no useful comment to plug state.

I'll look around for local sources of jets and then re-start this debate in a month or two when I have a chance to give it a good run! Will re-jet rich though before I start and get back to you all - but its nice to know I'm probably way off before I sieze her! thanks guys!