OzVMX Forum
Marque Remarks => Maico => Topic started by: Mad Max on May 31, 2014, 03:28:13 pm
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Hello Gents
I've just picked up my new toy, a 81 490.
A few questions:
Fuel/oil ratio?
Spark plug type?
I'm having trouble getting a consistent spark, coil resistance is 33ohms, and the pick up is 6.5ohm, sound right?
Assuming the poor spark is normal, what is the starting secret, carb tickle? Throttle opening?
Any advice welcome.
Regards
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25:1 mineral 40:1 syn
b8 or 9 es
not good with tech stuff etc muck around with timing so it doesnt bite you
hold down tickler till you see fuel run out over flow then if that doesnt seem to get enough fuel (plug not wet) put your thumb over overflow pipe and do it again
live on a big hill
enjoy mate great bike
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I run 30:1 with a synthetic oil.
You can optimise the spark by making sure all the earthing points are clean or run a seperate fire up to the coil. My 490 has the Motoplat Enduro ignition which has the external rotor - theoretically at least giving a better spark and smoothing the slow running out a bit.
Trick is to flood the bastid. Fuel must come out the over flow pipe. From time to time I lay the bike down on on its side and have in the past held onto the front brake and got a mate to lift the back end up so its doing an endo - gets fuel into the crankcase.
Give two or three slow priming kicks, go past TDC and kick like it owes you money. Repeat until it starts or you collapse.
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live on a big hill
;D ;D ;D ;D ;D ;D ;D
go past TDC and kick like it owes you money. Repeat until it starts or you collapse.
;D ;D ;D ;D ;D ;D ;D
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a worn out carby will give you no end of grief..... be sure its fresh.....
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a worn out carby will give you no end of grief..... be sure its fresh.....
Yes, that is a very good point.
No doubt I am far from being the only one that has seen a lot of bings worn out in the slide and slide bore.
They must have the rubber seal fitted at the top of the carby where the cable enters the carby cap cable adjuster, to prevent the fine dust from being sucked in. That fine dust/grit soon produces a gritty valve grinding paste like slurry.
It then doesn't take long to wear out the aluminum/alloy slide and bore.
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OK, thanks all. That gives me plenty of things to look at.
Does anyone have a PDF owners or workshop manual for a 490?
Regards
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I'd go for 25:1 with a mid range Syn oil. The 490 big ends are a bit on the small side for such a large engine and will survive at 40:1 but will last a lot longer with the extra oil at 25:1. I don't want to upset anyone by listing oils that aren't any good but be carefull when taking advice from your bike shop sales man as they push the stuff that gives them the biggest profit.
No one has mentioned the de-compressor. Make sure you use it or you will brake the kicker. So to start do the tickel thing if it still has the Bing or if it has a Mikuni just flip on the choke. Pull in the decomp and get it just over compression then still holding in the decomp give it all you have. As soon as it fire let go of the decomp. If you can't get it to go come back on and let us know what type of ignition and carb the bike is fitted with. If you are a skinny little bloke you should go to your local Maccers and start filling up on burgers and chips because they do need quite a kick.
I have a manual but it's a hard copy, if you are near the Brisbane southside you could get it copied
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Just do what most have been doing forever.....make sure you have plenty of mates in the pits to help push start the buggar....LOL ;D
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If you use the decompressor , they as easy to start as 125.
If they are timed correctly and carburettor is set correctly it should go in a few kicks from cold and 1 or 2 when warmed up
No big effort required to start them.
Its debatable sometimes , that they will run effectively for extended periods
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I've fitted the bigger late model 16mm decompressor to mine and that helped. I also took a little compression out of it by fitting the std 1.2mm head gasket instead of the thin one I had in it.
I've got a motoplat internal rotor ignition set at the std 2.2mm btdc and a Bing carb.
Mine starts pretty well now, haven't had to push it for ages!
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If you use the decompressor , they as easy to start as 125.
The only 490's that Iv'e seen start like a 125 are in need of a re-bore.
The late model decomp valve is actually 18mm not 16mm and they do help a bit. I have seen one 490 with a 2.5mm piston in it and a PVL ignition that will not kick start because it isn't possible to kick it fast enough to make a spark even with the 18mm valve. Push starts no problem if you have a hill.
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If you use the decompressor , they as easy to start as 125.
The only 490's that Iv'e seen start like a 125 are in need of a re-bore.
The late model decomp valve is actually 18mm not 16mm and they do help a bit. I have seen one 490 with a 2.5mm piston in it and a PVL ignition that will not kick start because it isn't possible to kick it fast enough to make a spark even with the 18mm valve. Push starts no problem if you have a hill.
That's why I lowered the comp a bit, so the motor will spin faster when kicking.
Mine used to be a bitch to start and often had to push it..now it kick starts no problem.
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get a husky..... ;D
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get a husky..... ;D
I've got 3.. they're no better ;)
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If you use the decompressor , they as easy to start as 125.
The only 490's that Iv'e seen start like a 125 are in need of a re-bore.
Sounds like you need starting lessons for 490's , fresh or tired they are easy to start with a decomp.
The late model decomp valve is actually 18mm not 16mm and they do help a bit. I have seen one 490 with a 2.5mm piston in it and a PVL ignition that will not kick start because it isn't possible to kick it fast enough to make a spark even with the 18mm valve. Push starts no problem if you have a hill.
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OK, my decompressor is not working so that will be a good start, (I have parts on order).
Are there timing marks on the rotor to check the advance with a timing light?
What does 2.2mm relate to in degrees?
Do these Motoplat ignitions advance the timing automatically (electronically?)
I dont need Maccas Sleepy, I'm a fat bastard!
Thanks all
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OK, my decompressor is not working so that will be a good start, (I have parts on order).
Are there timing marks on the rotor to check the advance with a timing light?
What does 2.2mm relate to in degrees?
Do these Motoplat ignitions advance the timing automatically (electronically?)
I dont need Maccas Sleepy, I'm a fat bastard!
Thanks all
What ignition is fitted to the bike? Original motosplat or the Bosch enduro or something else?
If you don't need Maccers then of to the GYM with you and start doing those leg things that the gym junkies do.
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sounds like a buy a 250 time ;D
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Set the timing with a dial gauge at 2.2mm btdc using the marks on the ignition.
Fit the decomp before you try starting it, you're wasting your time otherwise..
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Motoplat ignition fitted Sleepy. I dont think I'll be attending the gym, maybe the emergency dept if I do the the bastard going as I havent ridden a dirt bike for years.
A 250 would be smart Rossvickicampbell, but then I've never been accused of being smart!
I'm now out the bush at work until Tuesday so there will be no progess until then.
I will be replacing fork seals next week, any tricks I need to know (I've done them in road bikes many times). What weight oil and how much?
Thanks all.
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With the motoplat there are marks on the stator and rotor which the book specifies to line up at 2.1 +- .1mm btdc. The marks are only good if the rotor and stator are a matched pair, they have a serial number on both parts that should match. You can use a timing light but only to check if the marks still line up at around 3 or 4000 rpm.
The light can't be used to set the timing because as you move the stator the timing marks will always line up.
I have seen a mismatched set were the timing was advanced by about 10 degrees when the marks where staticly set. Nearly broke the owners ankle each time he tried to start it. I have checked the mark alignment by turning the motor over with a drill with the plug out and aiming the timing light at the marks which even at drill speed should be close to linning up(make sure the plug is still earthed and there is no petrol around). You will still have to use a dial indicator down the plug hole to set the 2.1mm.
The motoplats do have a bit of electronic advance built in to answer your earlier question.
Fork oil is listed as 20wt at 570cc per leg and 14 psi air pressure. This is a starting piont and the pressure and quantity can be varied to suit rider weight and track conditions.
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2.0mm is close to 22.5 degrees
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Here in the PNW myself and all my big bore Maico bros are running Maxima Castor at 32-1.
It has been my experience that as the Motoplat dies the 490's become increasingly difficult to start. The failure mode on 2 motoplat equipped 490's was that I could not get a fire lit by kicking (I have had lots of 490's that I have raced for years and know how to start them) then even pushing down a hill or towing the bike will not get it started. Time for s new PVL or HPI.
You're onto the decompressor, good!
If you are running the Bing make sure the slide is not worn, if the slide greets you with a big smily face get a new one.
Like the gentleman on the previous post, they like a wet bottom end, I run long vent hoses and will turn them up, tickle until you see a level build in the hoses and hold the throttle open for a count of 3, this floods the bottom end. A few slow priming kicks then get it just past TDC and give it a smooth strong stroke, do not "slap" at the kickstart. If it pops or kicks back shut the fuel off and hold the throttle wide open when kicking.
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I run Shell Advance Racing M in my Maico @ 32/1. It is a synthetic castor oil like the Maxima 927.
I had trouble starting my 490 it slowly got worse. I thought it was ignition. I got a new ignition from HPI in Belgium. It was $271.00 including postage to Australia. It kick started after 5 kicks when I fitted it and even started first kick one time. However after three rides it wouldn't start at all. After trying several different things I decided there was something else wrong.
Took the motor out and split the cases etc. Big end worn, but I think the biggest problem was probably a leaking ignition side crank seal. The bike was also running hotter just before it wouldn't start.
Anyway the problem may not just be one thing.
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Thanks all. My problem may well be more than one thing.
How did you but the HPI ignition KTM47? Ebay?
Can I change the crankshaft seals without spliting the cases?
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You can order off HPI's site
http://www.hpi.be/item.php?item=STK113