Page 1 of 4

engine decision

Posted: Tue Jan 26, 2010 9:32 pm
by mmjosh
hi i am wondering wheather to change my engine from a 948cc to a 1098cc reconditioned engine as it already has a 1098cc gearbox what do you think ?[frame]Image[/frame]

Re: engine decision

Posted: Tue Jan 26, 2010 9:35 pm
by aupickup
stick with the smaller one and sell the engine to me

seriously put the 1098 in

Re: engine decision

Posted: Tue Jan 26, 2010 9:42 pm
by mmjosh
ill put a picture on tommorrow of it and then i am going to degrease it and paint it

Re: engine decision

Posted: Tue Jan 26, 2010 10:59 pm
by bmcecosse
You need to record the change with DVLA - and tell your Insurance co.

Re: engine decision

Posted: Wed Jan 27, 2010 2:23 pm
by deano69
But isn't the 948cc engine supposed to be a better engine?Most comparisomes between the two seem to conclude this even if theres a 6mph speed differance with the top speeds when new.

Re: engine decision

Posted: Wed Jan 27, 2010 2:25 pm
by bmcecosse
It's a smoother engine - because of the shorter stroke - but the 1098 gives a lot more power! Partly because it's 16% bigger - but it also has a much better camshaft - and a better cylinder head. Put that cam and head on a 948 - and it' won't be too far behind - although will have to rev harder to make ultimate top power - which on both engines will be limited to much the same figure by head/manifold/carb. However -for ultimate best economy - the 948 should be better - and the 848 better still! Still looking for one!!

Re: engine decision

Posted: Wed Jan 27, 2010 3:16 pm
by deano69
848!Do they exist?

Re: engine decision

Posted: Wed Jan 27, 2010 5:16 pm
by mmjosh
added a picture now

Re: engine decision

Posted: Wed Jan 27, 2010 6:08 pm
by PSL184
I want to keep the short stroke of the 948 so I'm gonna put a 940 head on the 948 block with a 1098 cam, LCB manifold, 1.5" exhaust system and an HIF38 carb. Should out do a "standard" 1098 I should think :wink:

Re: engine decision

Posted: Wed Jan 27, 2010 8:56 pm
by MarkyB
There used to be a chap called John who did several MOTs in a 948 4 up and it was hard to keep up with.
ABS (Absolutely Bog Standard) looking under the bonnet but it went a LOT better than any standard 1098.

Re: engine decision

Posted: Wed Jan 27, 2010 9:12 pm
by bmcecosse
Hurray! That engine has the necessary rocker cover WITH breather pipe!

Re: engine decision

Posted: Wed Jan 27, 2010 9:15 pm
by mmjosh
i have a none breather rocker cover though :D

Re: engine decision

Posted: Wed Jan 27, 2010 9:17 pm
by bmcecosse
Throw it away!

Re: engine decision

Posted: Wed Jan 27, 2010 9:17 pm
by MarkyB
Put it on Ebay!

Re: engine decision

Posted: Wed Jan 27, 2010 9:21 pm
by mmjosh
what the non breather rocker cover

Re: engine decision

Posted: Wed Jan 27, 2010 9:41 pm
by bmcecosse
YES! It's useless!!

Re: engine decision

Posted: Wed Jan 27, 2010 9:53 pm
by mmjosh
the thing i dont understand is what is so bad about them ? :roll:

Re: engine decision

Posted: Wed Jan 27, 2010 11:08 pm
by bmcecosse
They don't allow the crankcase to breathe cleanly - so fumes and oil leaks soon errupt! :roll:

Re: engine decision

Posted: Thu Jan 28, 2010 7:07 pm
by mmjosh
non breather rocker cover[frame]Image[/frame]

Re: engine decision

Posted: Thu Jan 28, 2010 8:42 pm
by bmcecosse
You could braze a breather into it! Any decent competition A series engine has HUGE breathers connected to the rocker cover!