OK so I have the oil pump problem sorted out and have fitted new points and condensers I took it out just now for another spin. The bike is still bogging down and just not happy between 4-6000rpm!!
I originally thought it was running rich on the MJ which was part number 100,(Needles were set at second from the top) So I put in a set of 95's and set the needles to the middle groove. Went out again and still no difference so I'm now starting to think 'Ignition' or coil?
The only thing I haven't tried yet was to move the clip to the very top groove to make it run as lean as possible on the PJ to see if this cleared the problem.
I have set the timing at 2.26 mm BTDC and believe me it is 'spot-on'. The engine runs as 'sweet as a sweet thing' when ticking over and revs freely, its only when under load that the problem exists.
If I coax it past 6K in the first 2 gears it will haul ass as it should, providing that is the revs are kept above 7000rpm which sort of says to me that
when the bike is running on MJ 'only' things are OK. Like I say I have only recently bought this bike and it has been the subject of an enthusiastic (But rather amateur restoration) New parts include:-
Wiseco Pistons
Rebuilt Crank
New points
Condensors
Carb rebuild Kits (2.0 Slide Cutaways, PJ=30, MJ= 95,Needles have Y32 written on them??
Aftermarket Air Filter from Z Power (UK)
https://www.z-power.co.uk/merchantmanag ... p?pID=2061The Carb rebuild kit that was used is now under my scrutiny as the needles are 'Y32' WTF is that?? By rights from my understanding they should be 5DJ19 or at a push 5GL3.
Where can I get some proper needles??
As a bit of background I know a little bit about carburation as I have an immaculate and 100% original 1990 TZ 250A with 78 bhp at the wheel (Reverse Cylinder) and an RS 250 priller with better than 72 bhp at the wheel both of which I built myself.
The pics are of the old days when I was racing my 750 Kwack in the Manx Grand Prix. The motor was to H2R spec with a rare 3 cylinder Femsa ignition, it was housed in a cantilever Yamaha TZ 750 (OW31) chassis (late 70's early 80's)
All advice from you young'uns is greatly appreciated as I fully realize that things have moved on a great deal since the 80's.
Cheers
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FAQ
I have already replaced the MJ's with genuine Mikuni parts.
20 degrees might work at 11,000 rpms with chambers that WORK but.........
even 23 degrees kills the bottom end on the 500's.........
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