Scooterotica

I've been setting up with an EGT guage. It was definitely weak on full throttle with pj and lower main, it wasn't until the main was brought up that it cooled down. Performance and temps are no different with a 280 main with or without the powerjet, so I assume it's not coming in to play on my engine. I have also heard that it would need 10,000 rmp to come in to play.
I'm still not sure I have he jetting right which is why I was interested in other's experiences.
Does anyone have a powerjet working on a TS1 as I have only heard theory this far and nothing of a working example?

soulsurfer wrote:I've been setting up with an EGT guage. It was definitely weak on full throttle with pj and lower main, it wasn't until the main was brought up that it cooled down.

So therefore.....the PJ was not big enough?

soulsurfer wrote: I have also heard that it would need 10,000 rmp to come in to play.

And did you check the RPM when fuel started furiously squirting out of the PJ? I'd suggest it was well below 10k

drunkmunkey6969 wrote:

soulsurfer wrote:I've been setting up with an EGT guage. It was definitely weak on full throttle with pj and lower main, it wasn't until the main was brought up that it cooled down.

So therefore.....the PJ was not big enough?

Hmm, could be Do you think i should keep the main at 280 and increase the pj from 70 till it bogs down a bit and then lean out the main, therefore changing the ratio of powerjet:main jet?

I don't suppose anyone has some powerjets I could borrow, I've already spent a fortune on jets for this

Mike, when I was using a TMX 30 I blanked off the powerjet for two reasons.

1. It came pre-jetted from somebody who had been using it on a TS1 supposedly set up by Taffspeed and the powerjet was not being used.

2. I did some research and found a web site that claimed the powerjet on Mikuni carbs (and probably all others?) will not work unless the 'correct' type of air filter is being used, which creates enough vacuum to draw the fuel up.

I don't know how accurate this information is because you can't trust all that you read on the internet. However, as I was running open mouthed anyway it convinced me.

Thanks for the info.
Further information from another thread tells me that the power jet doesn't kick in until around 8k rpm on a TS1. If the powerjet ratio is increased or decreased, will this increase or decrease the vacuum required to pull the powerjet into play at a lower rpm and which way to to this?

a nice way to find overly lean or overly rich carbs without a dyno is to use a rev counter: go (any any gear, best 2nd) from tick over to full speed at a fully open throttle. it is easy to find rich/lean there by just listening. mark how far the engine revs out.
then mark idle, 1/4, 1/2, 3/4 with a needle or a marker on your throttle, and repeat the same process for all throttle positions. the throttle openings at which your engine revs further than at full throttle are too lean, the ones where it revs less are too rich.
cheers

ive used power jet carbs on both a 240(36mm dellorto )and yamaha 205 gp4 race bike (34mm dellorto) when on the stand and reving you could see the fuel being pushed out of the jet these were not reed valve engines i know i was told by taffspeed 20 yrs ago that reed valves dont work with power jets as they tend to flood them i know it was along time ago and things have changed or i misunderstood

My TS1 runs a 38mm powejet.....it bumped up the power by 3 BHP over a Mikuni 35mm non-powerjet with no other changes. No flooding issues.

drunkmunkey6969 wrote:My TS1 runs a 38mm powejet.....it bumped up the power by 3 BHP over a Mikuni 35mm non-powerjet with no other changes. No flooding issues.

Did you try a 38mm non powerjet as well, to see if the power gain might have been because the engine was capable of taking a bigger carb and little to do with a powerjet....??