Tuning Engine / exhaust mods?

[lazylobster]

Hi all, on a 650cc Model R, what sensible upgrades to release a bit more power and torque are suggested. 28mm carb, sports exhaust?

If anyone could recommend a good sports exhaust, from experience, I'll be grateful. Not worried about it being the loudest, but good flow and some noise.

Anything else, air filters or other? I'm not wishing to go down the Abrath route.

My thanks
Rob

 

[gordinir8]

I am not an expert but you can try a faster camshaft and maybe some head porting, maybe an exhaust will help a bit. Your engine has a 28 carburator already

 

[the hobbler]

With regard to exhaust, try Middle Barton Garage--I got my 'sports' exhaust from them about 3 years ago and I have had absolutely NO trouble with it. It is a 'single pipe' style and fits onto the normal exhaust manifolds. (it is a bit noisier than standard). It was not the cheapest exhaust on the market--but the old adage--buy cheap, and you will get cheap!
As mentioned by Thomas (Gordinir8), some head porting won't go amiss--especially the ridge just behind the inlet valve which is quite 'sharp'. Another useful addition (if it hasn't already got it) is electronic ignition---even the simple 'Hall effect' systems make an improvement. A 75/35/35/75 camshaft will help make the engine breath better. If you do carry out these mods I would recommend that you fit a 3-1/2 litre ally sump--(you can get them 'un-badged'), it will help the engine stay cooler. As also mentioned by Thomas, the carb on the 650cc engine is a 28mm carb, but Proietti in London sell a 29mm carb which, with the other mods, will give a performance boost--it can be fitted with the standard induction system or you can fit a inlet trumpet (with gauze, side-draught or down-draught).
Don't forget tho'--if you make it go too much faster, you may need to up-grade the brakes. You will never have a 'really fast' car, only a big grin--the main thing is that by sensibly upgrading the performance you will find keeping up with modern traffic much easier.

 

[Hugh Jarce]

Hi Rob

Here's my set up prior to installation some time ago now. 594cc with a sports exhaust from Middle Barton Garage. Perfect fit, straight onto the manifolds with a nice crisp sound to boot.

Cheers
Hugh Jarce (aka Gary)

 

[Paolo66]

I have a sports exhaust going spare for a reasonable price like the one Hugh Jarce has. It came with my 650 engine but the wife said it made it too boy racer so made me swap it. Its her car after all. I'm in Sicily at the moment so cant get you a photo but PM me if you're interested

 

[lazylobster]

Thanks for the pointers all. Some food for thought.
R

 

[fiat500]

. Some food for thought.
R

Here's a bit more for an indolent crustacean

If you have 650 engine and it's in good order you don't need any upgrades in order to enjoy the car in modern traffic.....that upgrade has already been done.

In town where 30 and 40 mph are the speed limits you will not struggle to keep up with traffic.
When you hit the 60mph zone you will easily achieve that speed without impeding other road users.
You will be able to exceed 60mph (I can't say by how much), but at higher speeds the engine will be thrashing quite frantically. This will also be the case if you upgrade anything on the engine to make faster acceleration and a higher, theoretical top speed a reality. Then you might feel the need to modify the gearbox to have a higher ratio; something that seems fraught with technical difficulties.
Anyone who really wants to be able to cruise at 70mph and above in a 500 has maybe bought the wrong model of 500 or should look at another type of car altogether.

In summary, although I understand the attraction of modifying engines and cars of all types, in my experience, especially with the 650 engine, there is no pressing need to fiddle with anything. I would spend your time and money on making sure that the engine as it exists is serviced and adjusted thoroughly to ensure that its inbuilt robustness is maintained.

(As for electronic ignition, I can't see how it will increase the power of the engine although in some circumstances it will help with reliability.)

There....I said it.