What is a good speedometer to buy?

[T Rock]

Will a high flow air cleaner make a noticeable difference ?

 

[Fabian]

Hi T Rock

Don't fall into the trap of removing the baffles from the muffler.
All you will have is an itrritatingly noising engine that looses a noticable amount of low and midrange torque, for the sake of a miniscule amount of extra top end power.

The best mods i've done (without pulling the engine apart) are to port the intake tube at the sharp turn radius and match port the intake tube to the engine intake port.
If you've got the larger 66-69cc engine, stay with the standard NT carburettor and replace the standard jet with a Dellorto No 82 for best power or a No 83 for reduced engine temperatures and improved smoothness.
You can try a No 84 if wanting even lower engine temperatures, though there will be a very slight reduction in maximum power but midrange torque will be further improved.

Fabian

 

[AussieSteve]

Hi T Rock

Don't fall into the trap of removing the baffles from the muffler.
All you will have is an itrritatingly noising engine that looses a noticable amount of low and midrange torque, for the sake of a miniscule amount of extra top end power.

The best mods i've done (without pulling the engine apart) are to port the intake tube at the sharp turn radius and match port the intake tube to the engine intake port.
If you've got the larger 66-69cc engine, stay with the standard NT carburettor and replace the standard jet with a Dellorto No 82 for best power or a No 83 for reduced engine temperatures and improved smoothness.
You can try a No 84 if wanting even lower engine temperatures, though there will be a very slight reduction in maximum power but midrange torque will be further improved.

Fabian

I agree with not removing the baffles, but I drilled two 4mm holes through the tail-pipe, just inside the end-cap, without increasing noise too dramatically, but it improved performance perceptably. Any more than that and it'll get a bit loud, (for my liking, at least).

On the subject of jets, I run a stock exhaust with only the above mod and a stock NT carb, 66cc (ZBox series 3) engine, port matching, but mine would be lucky to even run with an 0.82-0.84mm main jet, it would 4-stroke right through the rev range and foul the plug heavily. Even the stock 0.79mm did all of that. It runs nicely all through the rev range with an 0.72mm jet and the slide needle at it's lowest setting.

Unless you have an air leak somewhere, I think that all of these engines vary a bit and need individual tuning.

Tony at RSE suggested an 0.72mm for these engines right from the start and by trial and error I ended up with exactly that size. I get best performance, no 4-stroking and a clean plug, even with a 20:1 fuel/oil ratio.

 

[Fabian]

Hi Steve,

I'm posting this link, so the thread doesn't get off-track from the original title.
You can read my post on the first page, with regards to resolution of a serious problem:

http://www.motoredbikes.com/showthread.php?p=272403#post272403

Fabian

 

[hemi350]

with the carb tips and the port matching and a little money a gear change if its not to hilly where ur at to maybe a 36t will give u a good cruising speed over the stock 44t used in most kits now. what do u guy say, a topend increase of about 5 to 7 mph.