Hitchcocks Forum

My 2003 ES 500 bullet needs a rebore and new piston. Just wondering if I should change the barrel for an ally one. What are the advantages?

Better heat dissipation / cooling..
I'd fit 535cc alloy barrell and piston.. Same price as 500..

Hello Ivor--------The most obvious difference / benefit is just how much lighter the Aluminium barrel is.....ie}-- much less weight to lug around and better economy...............Your engine will warm up quicker (and therefore cool down quicker ).......Make sure you get a "quality assured" one such as our hosts offer.............I bought a "Cheapie" one some time back which had a casting inclusion in the pushrod tunnel..This showed itself as a nast black, oily weep through the fins, but only when up to running temp................We inserted an Aluminium top-hat type of sleeve which cured it completely....No cost for me but Mr. Average Owner would have to reach into his purse to pay for that sort of thing...so not really a cheapie in the end..........

If you decide to get an Ally one then you'll be going back to Standard bore I assume and will want a matching piston to that size.....Remember to gap those rings accordingly as well-------TIM, what's the ring gap for an Alloy barrel ??..............and don't forget that the liner protrusion "lip" might be different than the old barrell so do a clearance check for that new Head gasket you'll also be fitting .............Finally, I'd recommend that you fit a steel insert in place of the plain threaded hole found between the two pushrod tunnels as the Aluminium can be quite soft compared to the cast iron previously used and there's a real chance you'll strip the thread, so now's the time to do it........

And lighter although the Accessory Catalogue doesn't say how much. Note to Hitchcocks, you could provide this information? I have an alloy barrel ready to go on a 500 Bullet and it is much lighter than the iron one is all I can say!

REgards, Mark

If I fit the 535 barrel and piston can I use the same head?

the alloy barrel for a 500 is ±50% lighter.

thats ±8kg for a iron barrel and ±4kg for a alloy one

Forget the weight advantage, they look better, what more do you need to know>

Ivor, yes.


REgards, Mark

The only real advantage of opting for 535 is from the increase in compression...


Alloy barrel: Lighter and vastly better heat dissipation. More so when painted black. As an aside, I have a shelf filled with serviceable Cast-iron barrels that have by preference been changed out to Alloy. FAR superior item over CI.


The alloy barrels are all finished to Std bore size; 3.307 (They can vary somewhat, so do check your barrel!!) as such ANY appropriate piston fitted to it will be running with approx 0.002" more clearance than is optimal in a CI barrel.


Perfect for a Forged piston that requires a slightly greater skirt/bore clearance than a Cast piston would...


Ring gaps; 0.003" for each inch of bore dia.




CAUTION: If you are contemplating using the OEM factory piston, be aware that they have an excellent and well earned reputation for disintegrating. I pull the top end by 10,000km and inspect the piston rings and ring lands for wear. With full expectation of replacing the piston.


If the rings have been pinched tight, throw away the old piston!

Hi

Yes you can use the standard head on the 535 barrel.. Basically the bore is roughly 3mm bigger... You will need to jet your carburettor to suit the new capacity... And yes fit a forged piston while your at it.. You will get a compression gain by going to 535 so a bit more power.. I wouldn't bother going for the high compression option if you're leaving the bottom end standard..

Tom