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Re: which gearbox
Posted: Thu Apr 11, 2013 5:45 pm
by Avantone
Both OK but I'd say getting the gap between 3rd and 4th is way more important than the gap between 2nd and 3rd.
On that basis GP200 with the preferred bigger crown wheel looks better IMO.
GP200 vs. Li150 gearboxes:
The graph on this particular GT186 shows a peak power of just over 20HP.
With the GP200 box, changing up from 3rd to 4th at 7000RPM brings you into 4th at around 6000RPM and approx 18HP. Peak power is then within 500RPM and holds until 7100RPM and 75-80 MPH with a 20x47XGP200 (83 link chain) final ratio 4.7.
Stock GT186 Dyno Graph:
Re: which gearbox
Posted: Fri Apr 12, 2013 12:04 pm
by bazza3004
Avantone wrote:Both OK but I'd say getting the gap between 3rd and 4th is way more important than the gap between 2nd and 3rd.
On that basis GP200 with the preferred bigger crown wheel looks better IMO.
GP200 vs. Li150 gearboxes:
The graph on this particular GT186 shows a peak power of just over 20HP.
With the GP200 box, changing up from 3rd to 4th at 7000RPM brings you into 4th at around 6000RPM and approx 18HP. Peak power is then within 500RPM and holds until 7100RPM and 75-80 MPH with a 20x47XGP200 (83 link chain) final ratio 4.7.
Stock GT186 Dyno Graph:
Whoa now that's a reply,very helpful thanks Avantone
Re: which gearbox
Posted: Fri Apr 12, 2013 5:37 pm
by soulsurfer
Avantone wrote:
Stock GT186 Dyno Graph:
When you say "Stock GT186 Dyno Graph", are you sure the motor is a stock GT186 with no work whatsoever 'cos that's damn impressive and nowhere near what I've seen from a stock motor previously?
Re: which gearbox
Posted: Fri Apr 12, 2013 6:45 pm
by Avantone
soulsurfer wrote:Avantone wrote:
Stock GT186 Dyno Graph:
When you say "Stock GT186 Dyno Graph", are you sure the motor is a stock GT186 with no work whatsoever 'cos that's damn impressive and nowhere near what I've seen from a stock motor previously?
I grabbed a dyno sheet off of Lambretta Images for the power delivery profile rather than ultimate output.
http://www.lambretta-images.com/archive ... WhDcmS9Kc0
I wouldn't have thought it too hard to achieve though.
If the profiles right but the outputs optimistic, then GP200 is probably still right but with a 19t sprocket.
Re: which gearbox
Posted: Fri Apr 12, 2013 6:54 pm
by soulsurfer
Avantone wrote:soulsurfer wrote:Avantone wrote:
Stock GT186 Dyno Graph:
When you say "Stock GT186 Dyno Graph", are you sure the motor is a stock GT186 with no work whatsoever 'cos that's damn impressive and nowhere near what I've seen from a stock motor previously?
I grabbed a dyno sheet off of Lambretta Images for the power delivery profile rather than ultimate output.
http://www.lambretta-images.com/archive ... WhDcmS9Kc0
I wouldn't have thought it too hard to achieve though.
If the profiles right but the outputs optimistic, then GP200 is probably still right but with a 19t sprocket.
Ah right, I think this one had some work, I was starting to get small penis syndrome
Re: which gearbox
Posted: Fri Jun 07, 2013 9:46 pm
by bazza3004
I no its been a while since my original post but i finally decided to go down the Li150(italian) box route with 16x46 sprockets and im well chuffed with the improvement over the gp box i had in previously. Just need a decent pipe now . Anyone got out suitable forsale let me no. cheers, baz.