@Calum everything seems to be right. Ypvs works. I pulled out the plug yesterday, on the end of the ground electrode there were a small bit of carbon, i thought that was causing the problem. I swapped the plug, and same thing happens when the bike gets hot. Could it be pre ignition? I've read that carbon deposits on the piston could cause pre ignition when the bike heats up.

My thoughts are the standard airbox is quite sufficient if you remove the snorkel. you would only benefit from making that hole another few centimetres bigger and thats if you were fitting a larger carb which wouldn't really have much benefit unless you had atleast mild porting or head work zeeltronic ect ..

Pick up a cap from the Scrappy, any car one with the same pressure will work aslong as it has the old style rad cap. You'll pay Penny's for it.

@mhbikesnbits not restricted in any way. Always tuneable

buy yourself a thread restoring file - they usually have x8 different thread profiles on them

I may have one, stripped all the starter motor parts off my engine. Can have a look if you want?

Reassemble is simply the reverse of the disassembly procedure. That's a gem from Haynes and about ad helpful ad an ashtray on a motorcycle

@Glynn123 You said in my other post about me porting your cylinder, I advise you to send me the head aswell to get it machined to spec and derestrict it, as for rings, can't beat yamaha original ones for stock yamaha piston.

It'll be a 3MB cylinder. You want the 3MB head to go with it. 3BN heads are restrictive.

@Irongamer727 I rode a hornet 600 and it's pretty hard stock.

@britshgigolo make sure that you get the right width bearings as the original are narrower than the typical ones for the DT's diameter

@Irongamer727 that's really bad! im going to take everyone else advice and get a 4FU or 3MB cylinder instead with a aftermarket pipe and carb

@Calum isn't there a metal spacer as well? They can wear too if fitted and leak around the seal

@DTR-NSR yes they are narrower. Found out the hard way years ago when I couldn't get my cases back together......

@Bananper Get yourself one of these bud, give it a good swish around the bottom end and hopefully you will pick up any loose fragments; https://www.ebay.co.uk/itm/Flexible-Shaft-Bendable-Magnetic-Pick-Up-Tool-With-LED-Light-And-Strong-Magnet/391962870896?epid=15017009964&hash=item5b42cec470:g:L00AAOSwR0JUO~Ya:rk:72:pf:0 Also change your oil 3-4 times within the first month after the engine is rebuilt, just to flush out any remaining debris.

@NINJA Thanks, I have to get the A1 licence now :face_with_tears_of_joy: But the summer will be definitely fun!

Yeah, most use 2% as a rule of thumb I saw a chart on the auto-pump back in the days, as I recall it pumped out 3-4% af WOT, and way less just idling or at low throttle operations. Kinda shows you the beaty of the auto-pump. Some info here: http://www.dansmc.com/2_stroke_oilpump.htm

@Irongamer727 Twas what ever was in Motorworld at the time and cheap. And has always worked fine for me.

@Louis-James said in What clutch for a WR200 conversion?: The ebc heavy duty clutch. Use bandit 400 clutch springs

@jakeyboy See here; http://www.dt125.cz/download/Service_Manual-DT125R.pdf