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I am due to change the sprockets and drive chain on my Pulse Adrenaline and have come across a 17T front sprocket that should provide approx 13% extra top speed for a loss of 13% torque whilst using the standard 51T rear sprocket. Has anyone tried this?
To be honest, the more I think about the less I want to try it. Perhaps its more torque I need. /boggle.
Bjonk.
If you got more torque by reducing the front sprocket size you would get better acceleration but less top speed. The pulse adrenaline should be able to handle a 17t because it has smaller wheels, my Sinnis Max has a larger front sprocket and larger wheels than the Pulse Adrenaline and it handles the ratios just fine (good top speed and good acceleration. Your engine probably won't have enough torque to get the full 13% speed increase but with a couple other mods such as a free flowing air filter and a larger main jet you should be fine. Also a larger front sprocket will give better fuel economy.
Thanks for the input. I have decided to give it a go and will also look into the air filter/main jet mods.Quote:
Originally Posted by spencer2004
Bjonk.
You have the same engine as me so you most likely have the same carberettor as me too. If that is so then your inlet size will be 42mm, this filter here will fit http://www.ebay.co.uk/itm/170776343781 Apparently these can suck in water when it rains so I cut a coke bottle in half and put it around my air filter and it works perfectly, even in heavy rain. As for the main jet the stock size is 97.5, I upgraded to a 105 but I think a 107.5 or even a 110 would be worth trying, I got it from this auction http://www.ebay.co.uk/itm/220828656405.
Well, I went thru with the front sprocket change (17T) and must say that it feels good, much longer thru the gears and a better top end. Not noticed much of a difference off the mark either.
Going to try the filter you suggested. Any chance you can post a pic of the coke can cover? Need to see how to go about it.
Also, what exhaust have you fitted? I'm assuming you changed your jet because of it.
Thanks,
Bjonk.
I'll try to remember to post a pic tomorrow but basically you cut a 2 litre bottle in half, cut a hole in the lid end big enough to fit the filter through, stick it over the filter then secure it with a load of celtape. These filters make a brilliant noise espessially when accelerating hard, you will like it I'm sure ;)
Ordered the air filter and a friend has a couple of jets for me to try. What exhaust are you using?
Bjonk.
Well I'm using the stock one at the moment but I was planning on getting this and putting a db killer and some baffle wool in it to make it a bit less illegal. This should make the exhaust system a lot more free flowing and sound better, I'll need to up-jet after that to compensate for the drop in back pressure, I'll probably go with a 110 and see how that goes.
How did the exhaust/jet mod go for you? Did you use the exhaust linked above?Quote:
Originally Posted by spencer2004
Oh, post a piccy of the air filter mod if you can, i need to see it before i try it.
Thanks,
Bjonk.
Sorry about that, I'll try to remember to take some piccies once I get home. The exhaust and up-jetting went well; I have gained a few MPH top speed and I get better acceleration, I can hold 70 (indicated) almost constantly even up a slight hill. I put a DB killer and some baffle wool in my exhaust and it was much better, it's still a tad too loud for my liking but I aint too fussy. In total the exhaust cost me just under £50.
By the way I found out that the coke bottle mod is essential in the rain; I shortened mine by about an inch as I thought that it would help with the air flow a bit but water kept getting sucked in which stalled the engine while stationary and made it hard to start afterwards, I'd hate to think what would happen to the engine without a water shield at all in heavy rain.
Here you go, sorry about the bad angle, this was the best I could do without removing the carb. I cut the bottle in half then cut a hole on the lid end then cut about 10 - 15 verticle slits along the bottle at the lid end to allow it to stretch over the filter then I secured it with a load of electrical tape. Alternatively you can just cut a 48mm ish diamater hole and put the bottle on the carb first then put the pod filter on.
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