315r Choking Up When Idles

[sparky77]

I wonder if anyone can help?

I have a 2001 Montesa 315R which seems to choke up when it has been running between sections.

When I clear it out before a challenging section it needs to be revved flat out for ages before it clears and it splutters for about 5 seconds and sounds more like a chainsaw maniac has gone mad in the woods. This is both embarrasing and damaging to the engine. As I'm sure you'll understand.

The bike has not been abused and is running a new airfilter (tried it without oiling the filter and still does it) PJ1 oil at 80:1 with regular unleaded. New plug as per the manual etc.

Once I clear it out it runs fine for about 10 mins and then needs doing again. You could plod around all day as a novice and not notice but when you need it to be responsive this is when I have the problem.

I cleaned the carb out but not being an expert on this I didn't really know much about setting it up, but it runs fine when you first clear it out which I don't understand.

It's running a Kehin PWK carb. I was thinking of changing the reed valves as I have not checked these yet.

Another thing it has done to me is that when waiting to start a section facing up hill on idle it really chocked up badly and needed to be cleared out and it smoked something terrible. After clearing it was fine.

Anyone had any similar issues or got any advice? I'd love to get to the bottom of it.

Thanks

Sparky77

[motovintage]

It's running rich and loading up, drop the main jet one size and see what happens, common kehin jet avalable at most bike shops, the reeds are a good thing to check while you have the carb off, a frayed or chiped reed could cause the bike to run rich, also you may want to check the exhaust for carbon build up. Nothing against PJ1 products, you may want to experiment with other 2 cycle mixes, I prefer maxima 927, a lot of riders are using the maxima super M, silcolene and bell ray also make good 2 cycle oils.