6 replies to this topic

[liirge]

Hiya,
Over christmas i am going to be building my little 998 (A+) with a few goodies, and getting the mini back onto the road so i can at least driver her.
So far ive got (Or confirmed to buy)

- 12g295 Head (Im aware of the CR issues)
- Stage 1 kit
- SW5 Cam
- Alloy Duplex Timing Gear
- Twin 1 1/4 Carbs
- Good Rolling Road Session at Gerald Dale.

and i was in need of advice on a couple of points, after searching around the following thoughts came to mind:

1. Stub stacks, I was going to put K and N Cone Air filters on both carbs (I like the noise) and i was wondering would it be worth whacking some stub stacks in the cones, for that little extra bit of air flow.

2. Roller Rockers 1.3 Ratio, ive got the old rockers that came with the head the ones that are pressed like 2 pieces of metal together, but was thinking is it worth getting some Roller rockers to reduce friction on the valve train.

3. Lightened Flywheel, these sound like a really good idea to get the little engine revving faster, but once again worth it or not and advantages\Disadvantages.

4. Finally, will the standard clutch be fine, obviously ill be replacing it as theres no point not doing so. but do i need to uprate it with the extra power going through her? and if so which one do people recommend i believe there colour coded?

Answers to these question would be much appreciated, and any extra points anyone would like to mention would be very helpfull (P.S. i have plans for the gearbox later as i have one lying around in need of some upgrades and could be swapped)

Kindest Regards

Alastair

[Wil_h]

1. Stub stacks, I was going to put K and N Cone Air filters on both carbs (I like the noise) and i was wondering would it be worth whacking some stub stacks in the cones, for that little extra bit of air flow. Yes a stub stack is 100% worth fitting

2. Roller Rockers 1.3 Ratio, ive got the old rockers that came with the head the ones that are pressed like 2 pieces of metal together, but was thinking is it worth getting some Roller rockers to reduce friction on the valve train. probably not worth the money

3. Lightened Flywheel, these sound like a really good idea to get the little engine revving faster, but once again worth it or not and advantages\Disadvantages. The only real disadvantage is a slightly less smooth tickover, but with the SW5 cthis shouldn't be a problem

4. Finally, will the standard clutch be fine, obviously ill be replacing it as theres no point not doing so. but do i need to uprate it with the extra power going through her? and if so which one do people recommend i believe there colour coded? Standard clutch in good condition will be more than upto the job of this engine spec.

[liirge]

Thankyou very much for that! very usefull.
Im suprised the lightened wheel produces uneven tick over, how come?
anyone think of anything else im missing? for a fast road build?

[jayare]

I agree with Wil_h. If you have plenty of spare cash the 1.3 roller tip rockers may give you a slight improvement but in terms of £/bhp they aren't a good investment!

The lightened flywheel will affect the idle because the inertia of the flywheel smooths the rotation of the crankshaft - if you think about when the engine is firing, the most powerful part of each piston's power stroke only happens every 180 crankshaft degrees. By lightening the flywheel you reduce the inertia and you feel the separate power strokes more as a slightly uneven idle. Keeping with a mild cam (which the SW5 is) helps.

JR

[liirge]

Thanks you for replying

ahh, yes that makes more sense. so the idle might be a little rough i can live with that.
Yer roller rockers did seem rather expensive and ive heard they dont do a great deal for performance.

There's only one more thing i can think of is have i got to the point were it is a good idea to cahnge the Ignition, is it worth upgrading it? i dont the think the old budget can stretch to a megajolt, but i was looking at an aldon ignitor maybe or lumenition kit?

Any thoughts?

Alastair

[Wil_h]

Electronic ignition will improve reliability and are maintenance free. But they won't help with power or economy and without changing the advance curve of the dizzy you won't get the most out of your engine.

MS can be done for under £100, but £150 should be a maximum. Worth saving for IMO.

[liirge]

Really!! hmmm, ill have a look around the forum as i dont fully understand what Megajolt is completely.