Hi my first time on here and was wondering if anybody could help me ive just finished a restoration project my 2rk tzr and its been running and riding like a dream when yesterday it was riding fine all through the rev range and when I went to give it some when it reached the powerband @7000rpm it started spluttering and the revs wouldn't clime its completely fine when in neutral just reving engine but as soon as you go round block on it its spluttering in every gear. The power valve is pinned fully open and I have noticed it is leaking round the pv caps on each side of the barrel. Please help

Sounds like rev limiter to me.

Same engines as DT, they all stop at 7k rpm

Thanks for reply any ideas on how I can solve the problem?

First stop the pv leak as that will make the bike lean secondly what main jet do you have it should be around 250 with the valve pinned.

ive fixed the pv leak and it has a standard 180 jet and if it was the jetting why has the problem only just come about while I was ridding it do you know?

hmmm perhaps...

The main jet became unscrewed?

The slide needle bacame detached?

I checked and cleaned the carb yesterday and still getting the same problem

is the connection from the HT lead to the plug cap good? maybe cut back 1cm here

The coil ht lead and cap are all only a few weeks old but will check theres something rattling around in the exhaust so could that cause any problems?

yeah if it's the top of your piston

Has it ever been 7000rpm and over...

The symptoms you describe [ spluttering] sounds like you"ve too big a main jet in,, does it feel like the choke is on when it hits 7k, check plug colour, if too dark . go down 2 jet sizes, or drop the needle clip a notch,

Check air fitre too.

Its got a standard 180 in John so it cant be too big

maybe 180 written on the jet, but maybe some go faster johhny put a drill thru it.

The plug colour is black and yes it used to go all the way to the redline

stick a new plug in

I shal go buy a new one try it and let you know

1st rule of 2stroke.

Try another plug.

2nd rule of 2stroke..

Try another after that...

yes and the rough running can flood the crankcase so it may be helpful to remove the plug overnight to allow any potential excess fuel to evaporate away

Its cured the problem for the moment it had fouled the spark before and i cant,figure out why,its fouling them when its the standard carb settings