On the Search for a little advice... Pulse Adrenaline 125

So basically, I've had the bike for a while, but I think there may be something wrong with it (im not sure)...

Recently when accelerating, the bike has "dead spots" as such in the acceleration curve, I thought it could possibly be the spark plug so I bought a new Iridium Spark Plug for it and it seems the same as before.....

The bike has reasonable acceleration up to 30 apart from the dead spots, but anything after 30, the bikes just hardly responsive all the way up to 50 (55 on a good day), it takes a damn long time to get to 50, like 16seconds or so, which I dont think is right.

Things I've recently changed -

Engine Oil
Spark Plug
I've re tensioned the chain (though it had a bad winter and is quite rusty now, not sure if it needs replacing)

I've seen alot of people changing the sprockets to different teeth, does anyone know the best setup for acceleration without sacrificing top speed (since I dont have any).


Anyone have any ideas for me? Or is this just normal on these bikes?

Thanks in advance,

Jayke.

I've also just realized after going on a ride, that in 4th and 5th gear, it doesn't seem to want to go over 8k RPM, is the bike restricted in anyway?

It sounds like a fueling problem. Make sure that your air filter box dosen't have any debris inside and if your bike is a few years old you may need to clean the foam part of the filter with some white spirits. Your carburettor could be partially blocked up inside or the jets could have been changed for some reason by a previous owner or the dealer. Remove the carb, open it up and make sure that none of the jets are blocked with anything and make sure that they are the right sizes. The main jet (which is the biggest one) should be size 97.5 by default and the pilot jet should be size 15 (I think). You could alternatively get a fuel additive to clean out your carb so you don't have to open it up.

A 16 tooth sprocket would give you a bit more top speed, you can get one from here
http://www.chinesemotorcyclepartsonl...php?i=QM125-2V

A bigger main jet should give you more top end
http://www.ebay.co.uk/itm/MIKUNI-SMA...item2a24dd7f57

Other possible causes:
Brakes dragging
Defective ignition coil
Defective CDI unit
Intake leak caused by faulty orings or loose fasteners
Fuel hose clogged or too small
Incorrect valve clearences
Head gasket leak
Incorrect spark plug (should be NGK-CR8E or NGK-CR8EIX)

Wow you really know your stuff huh!

Thanks for the reply, since its so many possible things I think I'm going to send it into our local garage after trying the fuel additive. Hopefully that fixes it.

The sprocket idea sounds fun to try, but I'm also worried about losing any accelleration that I might have right now.

Thanks a lot!
Jayke

You lose a little acceleration by fitting a bigger front sprocket but you get the added benefits of not having to change gears so quickly while accelerating (which can actually help with acceleration), better fuel economy and more top speed.

You can eliminate some of the possibilities fairly easily:

To check if the brakes are dragging put the bike on it's center stand and spin the rear wheel and see if it spins freely, you can do the same with the front by either getting someone to push down on the back of the bike or by jacking up the front a little with a car jack (while on the center stand).

To check for intake leaks spray some flammable liquid (such as WD40 or brake cleaner) around the carb and intake duct with the engine running and see if the idle speed changes at all.

To check the fuel hose simply remove it and blow through it. Also there is a fuel strainer in the fuel tank which is accessable from the bottom, drain all the fuel, remove the strainer and check for blockages.

Valve clearances are a pain in the arse get a mech to do it.

To check for head gasket leaks feel around the cylinder block with your hands with the engine running at a fairly high rpm, if it is leaking you should be able to feel the combustion gasses puffing out.

Make sure the spark plug you installed is a NGK-CR8EIX


By the way how old is the bike and did you get it second hand or new?

Thanks alot again, I will look into these "fixes" as you will, the spark plug is the CR8EIX so no worries there.

And hmmm, I believe the bike is a 2010 plate, i bought it with about 600 miles on it a year back, it now has 8000 on the clock. :) Its done me well for the time I've had it though I really cant fault it other than these problems now.

Hey Guys I have a similar problem and it's the airbox not connecting to the carb correctly. At first I was getting a lot of water in the airbox, and only recently I've noticed the rubber seal that attaches on the back of the carb to the airbox doesn't stay on correctly. I've been considering getting a cone filter and taking the box off but, There are quite a few hoses coming off the airbox and i don't really know what to do with them. Any clues?

Yea. One clue. You don't use...

http://toolmonger.com/wp-content/upl...ose-clamps.jpg

With your climate, I wouldn't experimented with cone filter.

dont forget changing your oil filter as well and instead of cleaning ur air filter just order a new one its only 4 quid.

My Pulse Adrenaline is a 12 plate. 15 tooth on the front and fck know in the back ( didnt bother counting ) I tell u what with wind im doin 68mph and it freezes at 9.5 rpm. that was my max :)
it does wheelies on 1st gear really easy just give it a lil help on the back.
waiting for my cone filter to arrive from Philippines or smt like that.
got new main jet and need to order 16 tooth or 17 didnt decide yet.

Great bike, but rusts very quickly. Frame needs repainting often and all the screws needs to be changed.

but in general great ,reliable, cheap and fun bike.

repaint the frame with a decent paint that will last and get some ACF 50 its a anti corrosion spray.

Kennon

Or powder coat it (glossy only, matte is a magnet for filth).