5 replies to this topic

[neilfrancis]

Hello
I have got the engine of my 349 in bits and was wondering if anyone has some basic specs e.g piston bore clearance. It was particulaly noisey and Im trying to trace the reason. Also any tips on the engine build would be great.
Thanks

[jimbo349]

neilfrancis, on 12 December 2011 - 03:24 PM, said:

Hello
I have got the engine of my 349 in bits and was wondering if anyone has some basic specs e.g piston bore clearance. It was particulaly noisey and Im trying to trace the reason. Also any tips on the engine build would be great.
Thanks

The manual only specifies the min piston clearance so only helpfull when reboring the cylinder. The 349 motor can be a rattly old thing at the best of times mainly due to piston slap but the rings being dykes type still seal and they still run reasonably well. I have just completely rebuilt my bike less the big end and its sweet now, well crisp and has lost the death rattle it once had.

I have a theory the airbox is not that good at stopping grit into the motor with the short life of the airbox carb rubber not helping premature piston wear.

Good luck with the rebuild and please ask if your stuck with anything or where to get parts from.


James

[B40RT]

Classic Dirt BikeIssue 19, to make engine quieter, (page 32)you need -

"closely matching primary gears & hone the barrel conically so it was tighter at the bottom than top"

[neilfrancis]

jimbo349, on 23 December 2011 - 10:51 PM, said:

The manual only specifies the min piston clearance so only helpfull when reboring the cylinder. The 349 motor can be a rattly old thing at the best of times mainly due to piston slap but the rings being dykes type still seal and they still run reasonably well. I have just completely rebuilt my bike less the big end and its sweet now, well crisp and has lost the death rattle it once had.

I have a theory the airbox is not that good at stopping grit into the motor with the short life of the airbox carb rubber not helping premature piston wear.

Good luck with the rebuild and please ask if your stuck with anything or where to get parts from.


James

[neilfrancis]

jimbo349, on 23 December 2011 - 10:51 PM, said:

The manual only specifies the min piston clearance so only helpfull when reboring the cylinder. The 349 motor can be a rattly old thing at the best of times mainly due to piston slap but the rings being dykes type still seal and they still run reasonably well. I have just completely rebuilt my bike less the big end and its sweet now, well crisp and has lost the death rattle it once had.

I have a theory the airbox is not that good at stopping grit into the motor with the short life of the airbox carb rubber not helping premature piston wear.

Good luck with the rebuild and please ask if your stuck with anything or where to get parts from.


James

Thanks to everyone for the replies. One last question what oils do you use in the clutch and gearbox.
Thanks

[jimbo349]

neilfrancis, on 06 January 2012 - 02:59 PM, said:

Thanks to everyone for the replies. One last question what oils do you use in the clutch and gearbox.
Thanks

ATF in clutch or sae 20

EP80 in gearbox

Well that's what mine gets