Try feathering the choke as you hit the flat spot to see if that cures it. If so then it's a fueling gap coming off the pilots ( try lifting the needles a notch ) or partially blocked pilot circuit . Stock air box or individual filters ? If individual filters you may need air corrector jets fitting....

Simoniz / Sperex Tough black satin or Wurth satin black is the closest to the stock finish you will get and can be either cured in use or baked on.
Once cured they are both fuel and heat resistant and last for years.

Am I right in saying MK2 crank has 16 teeth for the camchain? But are the small ends 17mm for gudgeon pin? I think these are the best / strongest cranks for drag racing. Yes! Correct but also need to remember that they have a larger dia alt taper too so not a straight swap to the earlier motor with...

If it's that bent and it's not an optical illusion or the cam won't turn by hand in the head then there's no need for the checks I suggested in my first reply and the cam will need replacing.

11 month old post and Wooly hasn't been active on the forum since October 2018 so don't expect a reply anytime soon.

Fairly rare for one to be bent in normal use unless it's been chucked in a box with other parts, dropped or severely abused when being bolted down which would most likely damage other parts too. Best way to check for bend is set it between centers or in a lathe and clock the journals with a dial gau...

There's no point in taking out the location dowels as they are the same size on all 900 and 1000 motors.
Just use a 1000 base gasket as a guide to how much material needs removing as this will save you repeatedly test fitting the block.

Early 900 cases need the mouths opening slightly for the 1000 liners to clear. It is mostly from the rear of the case mouths. If the swap is being done on a built/running bike and the engine is still in the frame this can be done carefully using a half round file with some grease covered rag down th...

Don't bother with OEM idlers. Use the solid Liska or PMC type as they are much cheaper and have no rubber parts to fail. The Liska tensioner also replaces the rubber wheel with a sprocket. They will also last more or less forever as the only part that can fail is the replaceable roller bearing. The ...

42lbs is the max torque when using HD APE type studs.
For the stock studs early kwak manuals stated 25lbs but this was later revised to 29 - 31 lbs to combat oil weepage.

hi Guys, I’m working on my Z650F3 carbs and the manual says float height is 18.5mm in the Clymer supplement for later model section. However it isn’t clear as to where this dimension is set on the float itself. There is a flat portion where the hinge arm connects and then a step down to the curved ...

What main are you on now.
Shouldn't need to go up more than one size with just a pipe change especially with the stock airbox.
May not even need to change it at all depending on the flow of the pipe.

Most yrs jerry struggles to fill the stand so grabs the offers soon as only saying Phil Yep! same every year which is why i've had at least one or more of my bikes on the stand as backup every year for the past few. Can't expect to turn up at the last minute with a bike when they are needed months ...

Unless there is physical damage , float posts broken off, stripped air screw threads etc I've never had a set of carbs that are actually worn out.
The only non replaceable wearing area of the actual body is the slide bore and I've never had a carb become unusable because of that.

Can't help with the part numbers as i'm currently away from the workshop but the D1 crank takes the same bearings as all Z1, Z900, Z1000 through to Z1R D1. The D2 , ST and MK2 all use the later "Square cam cover" motor that uses a beefier crank and slightly different bearings. I suspect th...