Katana Owners Club U.K.

Fired it up today and snuck out for 30 odd miles. it's not right though.

What the engines had done.
Roger upperton put in new valves and cut the valve seats, he also rebuilt the crank.
I've fitted 0.5mm oversize Suzuki pistons.
new original cam chain
Other than that it's all standard,
Vance and hines pipe, std carbs only change is the main jets are 130
Air box std, no lid and no filter.


The bike gets hot very quickly, tickover is not stable, it'll be at 2k then I turn it down a little and it stalls...
CAM chain tensioner ! when I rolled back the wheel there was no noise, no rattle, I took the tensioner off checked it and all seemed fine put in another known good one anyway, before fitting it I gently put a screwdriver in the hole and turned the engine by hand, did it on the other engine too and they felt both the same. other tensioner in and it does the same, no rattle at all ?? also when I cam back from ride the wheel was locked in place ?

The first thing I thought was cam timing out, but I checked it loads of times and a mate checked it too, even so i'm pulling the cover off tomorrow and checking again, would also like to balance the carbs but it gets too hot too quick.

Advice and opinions please, really need to get it sorted as i'm at Cadwell Friday/Saturday/sunday and I NEED to race this bloody thing.

I'd ave thought that 130 jets and no real filter is going to be pretty lean with an open ish pipe... Can you try with the element in?

Sounds like its running very weak!
The main jets arnt going to effect the idle much..............that'll be the pilot jets and the fuel metering screws. Try turning the fuel metering screws out an extra 1/2 - 1 turn more than standard, and see what happens, they may need all re-setting to standard settings , whatever that is....................then working from there!

Vance and hines guide says 130 mains with the airbox lid off and filter in, tried it like that but it had flat spots and hesitation when opening throttle after constant revs, took the filter out and it was much better.
I set the pilots screws to standard which is 2 and a half turns out, i'll try an extra turn and see how it is.
How quickly do your motors get too hot to tough the head and barrels ?. this one takes just a minute or so, I've got a breather hose going to a can and that was smoking after a ride.
Any idea's on the cam chain tensioner ?

Fit a manual tensioner................then forget about it untill it starts rattling again!

But I'd also definately double check the cam timing again !

Well took off the cam cover to check the cam timing and everything is spot on, checked the valve clearances and all but 2 had were really tight, enough to open the valves a liitle I reckon, wtf went on there I don't know, I set all the clearances before putting the engine in the frame on Friday, I know they were all good and the timing hasn't slipped, it was correct then and correct now.
Anyway started it up and it sounds much better and isn't holding the revs up as it was, also stripped the cam chain tensioner right down and rebuilt it by the manual, installed turned motor backward then forward and it does what it's supposed to so i'm leaving it as is and not going to even try the running chack on it.
I turned the pilot screws out from 2 1/2 to 3 1/2 and again it runs better, if it needs any more then it needs bigger pilot jets but that'll have to wait until after cadwell, tomorrow i'm going to balance the carbs, bleed the rear brake (one slow piston) and get it all titied up for the weekend.

Well done mate, now go win.

Cheers Chris, I just re read my last post and it says i'm going to get it all TITIED up for the weekend, haha made myself laugh....should have typed TIDIED

Oh yeah, so you did, lol. Put fake boobs on the fairing maybe?
Well if it distracts the others enough to let you win then go for it