had a tapping noise in what i thought was my top end piston slap so i had a re-bore and fitted a makita piston kit with RIK rings and the tapping noise has remained. the piston was supplied by me and given to the shop with the barrel with the correct clearances. The ring end gap is within spec also. using a br9ea spark plug
so my question is how would i know if my con-rod is bad or the bearings. on last rebuild 110 or so miles ago there was no play up or down and minimal side to side. i have replaces the little end bearing as-well.
the bike a had previously seized due to cheap piston rings failing could i have a slightly bent con rod ? (i didn't check previously) how could i check accurately
I would imagine, although will have to check, that you would need to dismantle the crank to check. I will have a read about it tonight see what I can find.
Don't get disheartened mate, two strokes are naturally noisey. It could be the powervalve clearance mate. If there was no evident play in the con rod or bearings then I'd start off assuming it's not them. start with the easy things are work the way back down. I'll have a little think tonight when I finish work and reply.
the barrel is only .25 oversize powervalve is clean and practically new just taken out of doner engine. had a look up exhaust port yesterday and the piston is clean no scores or anything rings are intact. bike starts first kick like i said only done 110 gentle miles on this piston. no air leaks exhaust is sealed nicely no blowing anywhere. im at a loss.
i did have 2 rear wheel lock ups on other pistons pulled clutch in and costed to hard shoulder there pistons were fine with no scoring ether so i assume they wernt seizures. my next thought would be a tranny issue
Ok, sounds like you're doing the right thing here.
My next point of call after a lock up would be drain the gearbox oil. If it's a transmission fault then there will be signs in the oil to say what has happened. Not a lot can go wrong in the tranny, so if something does go it'll be the gearings, which in turn will take out the gears. But I'd be very surprised to see this. Only way I imagine would be if they didn't have oil in there for ages.
i have drained the oil and flushed it through twice (no signs of metal fragments or filings) this bike has a mind of its own things don't add up. stupid bike
Slightly of topic what plug do you use my bike came with a br8es but Haynes says br9es which im now using ? i believe the 9 is a colder plug its has never fouled so far
will change plug when i can get to a shop got another problem i took the clutch side cover off to inspect but now i cant get the kick start back in the cases and i cant get the nut off the lever to dissemble properly :( just wrestled with it for 2 hours, pissed off isn't the word !! any advice ? need a new gasket now anyway
update Pulling engine out of the frame today going to make a good engine from the 2 i have, just for peace of mind hopefully it all goes well just ordered full gasket kit and all engine seals :) is there anything else i may have forgot ?
If it were me! (and sorry for not looking last night, I won't lie, I forgot) I'd replace all the gearbox bearings, and whilst you're there the mains, and whilst you're there the con rod.
Gearbox bearings AT LEAST! They cost £20 for Koyo set of decent bearings. Top quality, they're done then!. Mains are more expensive but if you've got the crankcases split well worth doing. And the con rod varies depending who you go with. I've gone forged but to be honest, PJME recommend LONG and say they're very good and are half the price.
Everything can be done in a domestic household, bar the crank rebuilt. Yamaha charged me £30 to rebuild the crank, I supplied the parts, which I thought was a BARGAIN!
If you need any engine rebuild help feel free to PM me!
ordered Athena gaskets and seals all around and a genuine yammy head gasket i have sitting in the garage.
i will be replacing all bearings, except the crank wasnt done long ago. but depending if theres any metal floating around in the tranny i might change my mind,
iv got second engine off a 2003 bike which had a 2000 mile or so life span before a mate totaled it a month after buying it " was mint" :( i brought the engine and a few other bits i thought would come in handy. will use crank out of this engine, and probably most of the gearbox, "engine is already split otherwise i would just drop that lump into my bike"
any advice on how to put a kick start back with it still attached to the casing, couldn't get that nut off to save my life. felling defeated by a simple mechanism
