6500km valve adjustment req`d??

[topaz6turbo]

Hey, a quick question. My scoot has been loosing top speed over the last month. Flat out with no wind on flat ground it wont go over 95kmh. I thought it was due to the 10 weights, so fitted the 12s and its exactly the same. Would it be valve adjustment due, or a worn belt or any thoughts? Running fine and grunts to 80 nice and quick, but just lacking the top end. Any advice or help is welcome!
Thanks
Holty

[wordslinger]

..it could very well be your valves out of adjustment, or a worn belt...

..if you've never adjusted them, with 6500 km, i'd put some money on the valves..

..normal lobe and rocker arm wear occurs over time..this causes a greater gap betwen the arm and the valve stem, which keeps the valves from opening as much as they should, which pulls in less fuel mix...

..my A50 calls for adjustments a 2000, 4000 and then every 4000km....

..gradually dropping top end, with everything else running fine, is a good sign that they are getting out of spec..


peace

[marioG]

Could it be cold weather?

Cold air in intake system and less gas...

ive got 85 on the rain and wind....gonna try to adjust air/gas...screw

[wordslinger]

Could it be cold weather?

Cold air in intake system and less gas...

ive got 85 on the rain and wind....gonna try to adjust air/gas...screw

..i lose 5-8 mph or so in the rain, and the weather is getting warmer, so i wouldn't think that's it's due to the cold...

..and again...these 4-strokes require periodic valve adjustments...

..it's just the nature of the beast...

 

[zombie]

The air /gas screw ONLY affects the idle Mario. You could tweak it a little to adjust for the best setting. They all need this done every so often, but it will not affect the running of the scoot. You could add double the dose of Sea Foam to the fuel. If your main jet is getting varnished, or clogged from fuel additives a couple tanks w/ this may bring it back for you. Also check, and clean the air, and fuel filters. A new spark plug may just be the ticket also. As the plug wears the gap increases, and the performance does drop. Add that to the valve adjustment, and I believe you will be good as new

[grazo22]

My scooter massively lacks performance even with a new plug and a totally cleaned out carb. I've got a fuel filter, air filter, drive belt and dr pulley 13g rollers on order. Also will do the valve adjustments while i'm at it. Could the valve adjustment be the reason I'm running lean?

[zombie]

Yes! It would not allow enough fuel mix into the jug before closing. This amplifies itself in heat inside the cyl. so it is best to have a shot at adjusting them. A before, and after compression test is also a VERY good idea. If there is a burnt exhaust valve from the heat, that is the easiest way to find out.

[wordslinger]

My scooter massively lacks performance even with a new plug and a totally cleaned out carb. I've got a fuel filter, air filter, drive belt and dr pulley 13g rollers on order. Also will do the valve adjustments while i'm at it. Could the valve adjustment be the reason I'm running lean?

..yeah, whatzombie said...and...

...and i'm not sure about your rollers...i heard topaz talking about 10s and 12gram rollers...

..couldbe that the 13s are a bit heavy for your scoot....

[Cortez]

...and i'm not sure about your rollers...i heard topaz talking about 10s and 12gram rollers...

..couldbe that the 13s are a bit heavy for your scoot....

Stock are 14g, so..

[zombie]

There may be a vacuum leak (loose hose) or several other small things going on. Post back once you give it a good going over, and we'll take it from there.

[topaz6turbo]

Ok, I run full synthetic all day everyday in everything I own. It has an Iridium plug thats 2500km old and has run on premium (98) fuel since day dot. It has no airfilter currently (full airbox there just no filter) as I am going to fit the bigbore kit, and thought I would try it without a filter around 4 months ago, and its still sitting on the shelf in the garage, never re-fitted! I did something the other day and run plain simple basic fuel thru it, and I reckon it gained top end by around 5kmh! It had 1500 springs in the back end, a dr pulley variator, 12g weights, a 110 main jet and the free flowing pipe. I am going to try the tappets this weekend and see if that helps, as its either them or the belt I reckon. If that doesnt work, it might be time for more power and fit the kit!!!!
Talk soon, and will update once adjustment made.
Holty
Ps, what the hell is seafoam???

[Cortez]

Ok, I run full synthetic all day everyday in everything I own. It has an Iridium plug thats 2500km old and has run on premium (98) fuel since day dot. It has no airfilter currently (full airbox there just no filter) as I am going to fit the bigbore kit, and thought I would try it without a filter around 4 months ago, and its still sitting on the shelf in the garage, never re-fitted!

Um, that's not a good idea.

[zombie]

Put a filter in it. Even dust can accumulate inside the cly/rings, wearing everything out. Sea Foam is a fuel additive that is primarily Propanol. I use 1oz. per tank every third tank full. It is GREAT at keeping the carb clean, rings free, and carbon to a bare minimum. Running no air filter for sooo long I strongly suggest you find some, and run it thru the next 3-4 tank fulls.

[wordslinger]

..carb cleanin' a comin'............

[topaz6turbo]

To tell the truth, it would give me an excuse to fit the kit and be done with it. I need more power, and figured the thing would have clagged up by now, but still going..... I am thinking next weekend is a 3 day weekend for us, might be a chance to bolt the thing togetehr and not bother with the valve adjustment..
Will keep you posted!

Holty the free breather....