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315 Cota- Noise.....But Not Sure


lampshade
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Morning all,

Bought a 97 315 the other day with a top end rattle, seems all pretty original. Managed to source a barrel,piston and rings from ebay which is in good condition.

Replaced the little end bearing,gaskets etc etc.

Put it all back together and the rattle from the top end has seemed to have gone, but now i can seem to hear a noise but not sure where from, just doesnt sound quite rite.

Pulled the cover off and had a pull and play with the flywheel and doesnt seem to have any play in it.

The big end on the conrod didnt seem to have any play in it also. 

So.....Just wondering what it could be? is there anything else that seems to make these engines noisey? 

Iv had plenty of trials bike and enduro bike but always been modern, so not up with the older stuff, The engine seems to pick up really slow from the bottom end but i do have some boyesen reeds on the way which i am hoping will improve this. 

Any info or common problems with the engines or the carbs i am happy to hear. 

Regards, 

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51 minutes ago, teamferret said:

My brother had one of these and it ran as rough as a bag of spanners if you went any more than 75:1 on the oil mix. It really is almost a case of just showing the petrol the oil as they don't seem to like it

Thanks for that, so you dont think it could be the mains etc? 

I dont know if there is a way of checking without splitting it open. 

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15 hours ago, jonnyc21 said:

I hear the 315 is especially susceptible to detonation, try some premium fuel if you haven't already, if you have you might even try a mix of 50/50 race fuel and premium.

best of luck.

Thanks for that, you think that is where the noise could be coming from? 

Also has anybody any idea of how easy the forks are to service, paiola ones not showa, and same with the rear shock, will it need gassing or just a good clean and looking over. 

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3 hours ago, oni nou said:

https://youtu.be/uWehB1_yv84 [forget  the GasGas reference] Jim Snell has been very good to you.

by now I would think that your rear shock needs gassing.........if it has a schraeder type valve or rubber membrane type fill port already fitted[if not it will need one] then you can just buy a shock pump/needle kit  that goes to 300psi [hand operated,looks like a bicycle pump] off Ebuy for £40 and pump it up with air yourself[ [air is 78% nitrogen 21% oxygen  approx.] purists will waffle on about pure nitrogen being essential blah blah but in reality purging the shock chamber of 100% of all oxygen etc is going to be difficult and you personally will not know the difference between air that you fill yourself  and nitrogen from a service centre [expensive if they rebuild the shock at the same time which they will no doubt persuade you to do.] £150 ish

The difference[ in a trials shock] between air or nitrogen used as a spring is negligible the real consideration is the oxygen moisture content which is what of course causes corrosion[unlikely to be a major problem in the shock chamber] The fill pressure in rear shocks is usually around 200 psi or more perhaps 220 psi ......its such a small chamber it does not take much filling.The difficulty is making sure you do not lose much when disconnecting the pump which is best dealt with by over pressurising slightly.......once filled do not try to check the pressure with a gauge or you will lose half the pressure in the process putting the gauge on and off.

Again, bloody perfect bit of info, and the plus is i have a shock pump at home!!

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8 hours ago, lampshade said:

Thanks for that, you think that is where the noise could be coming from? 

Also has anybody any idea of how easy the forks are to service, paiola ones not showa, and same with the rear shock, will it need gassing or just a good clean and looking over. 

Can't say for sure it's the sound but it's a possibility.  And in the grand scheme not a hard one to test.

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On 2/24/2018 at 8:40 AM, nigel dabster said:

albea/sad boy? or private seller? new?

From trials bike breakers on ebay, new little end bearing and gaskets, just seems to make a scraping noise from the barrel....or seems to be, but noy sure if this is just normal engine noise from the earlier modes.

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  • 2 weeks later...
 

if they are albea rings.......have a look on 315 owners page on FB lots of experts on there. If the rings were new im assuming they are the eastern european made ones, as the genuine ones are so rare they are unobtainable, i had a guy fly a good second hand set over from canada!!!

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