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Post by strat on Mar 27, 2010 11:38:04 GMT 1
mmmmm, I'm not to impressed with my valve really on its powerjet carbs, they make it feel difficult to get the most out of it, like if the throttle isn't chomping on the throttle stop then its like they aren't working, they have blocked only the once mind since running the bike.
Wondered if I should just bung in some 31k mains and bung up the powerjets, or would it be best getting some 31k carbs, or early aircooled carbs, not that interested in the hassles some people get fitting PWK's.
I could live with it but it's just a bit annoying. (and slow)
ps. Carbs are ballanced and set up as the book says.
Strat.
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Post by dredge3 on Mar 27, 2010 21:24:26 GMT 1
What size jets are in?
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Post by strat on Mar 27, 2010 23:34:28 GMT 1
Dredge, the mains are a couple up from stock due to a slightly modded airbox and the old big can Allspeeds it is fitted with. Gary, you are most likely right. The powerjets work on the vacuum or venturi principle don't they? I had a Yamaha TT600 trailie once and it had one normal carb and the second carb worked on a vacuum off the other......pile of shite. Sometimes go like stink and try and throw you off the back and other times it was like a grandma riding it  A bit like my Valve, generally ok, but when you give it welly it seems a bit feeble, then sometimes it goes well.....these powerjet carbs were for emissions weren't they? If yes goes to explain a lot  cheers, Strat. ps. just to add, my previous powervalves were all 31k's, all had 31k carbs and were much gruntier and had more top end than this one, which is actually a 31k engine, with 1UA barrels but powerjet carbs.... pps. due an MOT next month so might get a compression check done too. ppps. anybody got some 31k carbs they don't want? |
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Post by dredge3 on Mar 28, 2010 0:50:55 GMT 1
I have 31k engine. I had 31k carbs. nothing but problems with throttle sticking due to slides. Got a pair of 1ua carbs and top end was much much better. Still having jetting problems. The problem is...all the carbs are worn at this age. You may get a good old 31k pair or a good pair of 1ua carbs. I would like to know which ran best when new
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Post by looey on Mar 28, 2010 8:59:28 GMT 1
I know 31k carbs are recognised as better and easier to setup but my naked F2 with a stage II Taymar tune still had its Powerjet carbs with 310 main jets (yes 310) and it rode faultless and was proper proper fast. Only point I'm trying to make is that the performance/speed issue won't be due to the type of carbs (especially on a pretty much std tune engine) but only maybe if they are worn, faulty or setup badly  I would suggest maybe trying to borrow a pair of carbs from a bike with similar mechanics and eliminate if it's carbs of something mechanical (low compression et.c bla bla bla). Anyway..............  |
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Post by dredge3 on Mar 28, 2010 11:46:40 GMT 1
Just looking at the net for spares. The needle jets alone are £20 each. Thats £40, then needles jets gaskets valves. Its cheeper buying new carbs
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Post by strat on Mar 28, 2010 11:52:07 GMT 1
It's cheapest just getting my compression checked I shall start there! Looey....badly set up carbs.......  Strat. |
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Post by strat on Apr 2, 2010 12:42:45 GMT 1
Just done compression check and got good readings of 118psi on each barrell  So more umph now needed. Strat. |
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Post by looey on Apr 2, 2010 12:58:14 GMT 1
Looey....badly set up carbs....... Strat. "maybe if they are worn, faulty or setup badly" |
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Post by strat on Apr 2, 2010 15:55:50 GMT 1
Yes Looey  31k carbs needed to try or buy please. or some aircooled 28mm ones ;D Strat. |
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Post by dredge3 on Apr 2, 2010 21:32:44 GMT 1
I got 20psi lmfao. The compresion testeri have is a peice of crap for bikes. 3ft long with 5 connections. Still,i thing its strip time.
Stuppid thing is, that doesnt make sence.It starts from cold first kick everytime
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Post by mellow on Apr 2, 2010 22:38:32 GMT 1
if its any help my F2's powerjet carbs work fine pulls to redline and upto over 100mph on the speedo easily |
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Post by strat on Apr 3, 2010 12:30:12 GMT 1
ok.
Mellow on the private race track ahem...how far past 100mph?
Mine has no fairing remember and flies upto 90mph but getting it past 100 is possible in 5th, but 6th is a waste of time as down come the revs and down comes the speed!
Unless on a certain private track with a steep hill where it always goes past the numbers.....ahem!
This is the slowest valve I've owned and its the only one ever to have powerjet carbs, so I could be unfairly blaming them.
Don't get me wrong, it can easily keep up, even out pull my mates 2003 Ducati 750ss upto a certain speed, but then it all seems to tail off and feels too feeble at the top end!
So far it has had the airbox inlet opened up a bit and the trumpet removed, the main jets are 2 sizes bigger, can't alter the powerjets, its fitted with old large can allspeeds too.
Is a 31k bottom end with 52Y cdi and 1UA top end.
Maybe its time for some porting work, I was hoping to get more umph from carbs/airbox/pipes but it doesn't look like I'm going to get anywere fast just doing that.
Strat.
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Post by mellow on Apr 3, 2010 18:34:34 GMT 1
mines standard......i think.........lol..........and has regularly been upto 120 on the clock .....even went past one of them 350 lc's in nottingham in 5th gear ;D ps ..............all on a "private track" lol ;D |
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Post by Norbo on Apr 4, 2010 11:35:07 GMT 1
I like F2 carbs . they are newer and made for a bike thats has more BHP as standard . for a tuned moter 31K carbs can be a little better and racers do block up the power jet and run a bigger main .
But my F2's both run spot on with tstandard carbs with standard jets .
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Post by dredge3 on Apr 6, 2010 21:45:23 GMT 1
I was looking at my Haynes and it liste dpowerjet carbs as 1UA 00 mine is 1UA 10..anyone?
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Post by strat on Apr 8, 2010 22:11:00 GMT 1
Sorry can't help, but I'm sure this has been mentioned in the past but maybe on the RD-forum, which as we know aint too hot at the moment  I have found what was wrong with my bike and it cost £7 to fix All it was in the end was incorrect gearing..."what?" I here you say, but its true! My bike was fitted with a 110/90 back tyre, not a 110/80 as should be, so a while ago I fitted a 41t back sprocket instead of a 39t to help compensate for the too tall tyre, but it still struggled to pull 6th gear unless it was perfect winds or down hill! So today I fitted a 16t front sprocket instead if the 17t and now....well what a transformation....6th gear now is usable, if anything its a bit short now, but 105mph at 9400rpm in 6th with me sitting up is much better, plus you can now slow in 6th and it will pull itself back up to speed which it couldn't do before ;D Naturally if I thought the back tyre was going to cause such an effect I would have changed the tyre ages ago...the tyre came on the bike when I bought it and its hardly worn in yet! So some happy motoring to come now ;D Happy Strat. |
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Post by strat on Apr 9, 2010 22:38:20 GMT 1
Compared to standard F2 pipes that were on it the allspeeds are good, compared to my previous 3 ypvs engined bikes it is still weak. My Black LC2 with early Micron GP pipes would hit 110mph with no fairing and sat bolt up right with me and the future Mrs Strat on the back (probably tuned) The LC/YPVS Hybrid had a silly tune and the last LC2 had the small bikini fairing on, both had Nikons and would go 110 mph easy too. I did change the hybrid to Codnors and it still went awesome too. So I haven't tried different pipes on this Valve, but finding anybody remotely close to try with a Valve or RD round Cleethorpes/Grimsby is like looking for hens teath Strat. |
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A bit like my Valve, generally ok, but when you give it welly it seems a bit feeble, then sometimes it goes well.....these powerjet carbs were for emissions weren't they? If yes goes to explain a lot 
