OzVMX Forum
Marque Remarks => Maico => Topic started by: ola_martin on June 04, 2013, 05:22:16 pm
-
Finished the assembly on my 490 last night.
(http://i1222.photobucket.com/albums/dd485/ola_martin/945150_10151526939433423_373703911_n_zpsaef8a7b2.jpg)
But it won't run.
It fires up quite easy, runs ok up to about 1/4 to 1/3 throttle, then it quits.
I use a Keihin 38 flatslide, and got reccomended pilot42 and main 170. Tried this first, rode a little on 1/4 throttle and the pipe got blue right away, and wouldn't run on high revs at all.
So I figured it was lean, and just upped to the biggest jets (pilot55 main 185) I had, to try. It's exactly the same. If I just keep it on full throttle it stops, and then the sparkplug is wet.
But it doesn't sound rich when I do it, and if I crack it open real fast it revs up for about a second or two before before it gives up. Sounds just like if you where to slowly kill it with the rear brake while keeping throttle, no blubbering etc....
So I'm thinking if it could be the ignition, std motoplat, adjusted by the marks to about 2mm, can't remember what the book said, but like reccomended in the owners manual. Can the markings be off, so it's way late?
Or does it have a two step advance, and the rev mode isn't working?
(http://i1222.photobucket.com/albums/dd485/ola_martin/945826_10151526940303423_1724949107_n_zps9bff66a9.jpg)
(http://i1222.photobucket.com/albums/dd485/ola_martin/781_10151526940793423_1476513917_n_zps5719aa84.jpg)
-
Fuel blockage? Float level too low?
pancho.
-
Fuel not blocked, haven't checked float level, but brand new carb. And sparkplug is wet when it has stopped....
-
Check the washer between the main jet and thee emulsion tube....
Sometimes it is a washer, sometimes a open tube designed to stop bypass between the main jet and the holder.
-
OK, thanks, will check, it's a Keihin PWK 38mm by the way.
-
Despite the hiccups, you've done a great job mate. That's a credit to you the finished project, just hang it up in the shed ;) ;D
-
Thanks buddy, but my other bikes are just sitting on their stand, so I hoped this could be a racer... ;)
-
Dodgy kill switch or not earthed well enough?
Nice job btw
-
Thanks buddy, but my other bikes are just sitting on their stand, so I hoped this could be a racer... ;)
Geez they must be flash as Michael Jackson!! :o enjoy racing this beauty then ;D
-
Be interested in the result on this one - I have a KX250 which behaves the same way :P
-
Take the fuel bowl off and see if the fuel flows freely. Might be a incorrectly installed crank seal. The ignition timing could be way out.
-
I've had a bike do exactly that and it was the main jet baffle fitted upside down touching against the bowl and blocking fuel from getting to the main jet!
-
Thats a real nice Maico mate... and I am not a Maico sort of man.... but I can really appreciate the work you have put into that.
I have built a few bikes that have done exactly as you have described....
I might be unlucky, but both times it has been drawing trans fluid up through the centre cases under high RPM, but actually idling okay.
Both times I had to re-split the cases and use good quality three bond (Yamabond) on the case halves after gently 'lapping' them to get the best sealing surface.
I hope for your sake that isn't the drama..... but something to ponder.... are you having to clean the spark plug each time?
Hardo
-
Was worried about the same, either between crankcases or crankseal on primary side.... It does smoke a bit :(
Don't have to clean plug, but will take quite a few kicks if I let it die on full trottle.
-
Is the fuel tank venting properly? J
-
Yep.
-
Correct diameter fuel line? Is enough volume of fuel getting thru.? J
-
I think so, I've taken off the hose at the carb, and it flows quite good. Anyway, if it didn't get fuel to the carb I would think it would at least rev for a few seconds, and not quit so fast. I've ridden it for a few minutes on 1/4 throttle no problem.
About the floatlevel, the Main jet sticks quite a lot further down than the pilot, wich it obviously runs on.
-
Paul is the Maico guru on here but he hasn't responded yet. Perhaps send him PM he may be able to help. J
-
sounds ignition, like not advancing in particular, especially if the pipe just about went red after a short slow revving run. Put a white paint mark [i use white 'twink' correction fluid] twink the rotor across to the case or something stationary at say 2mm before tdc then strobe it to see what it's really doing, also make sure it hasn't sheared off the key locating the rotor [or flywheel] not familiar with their system but just food for thought. Had something similar more than once on the old TT250 Yams, unrelated system i know but used to stuff the cdi box & stay fully retarded [no misfire] just barely pull itself along & glow the header 'red' in the dark. Wouldn't [couldn't] rev but choke sort of helped to get the revs up a bit. Sorry--digressing again. Carry on & good luck.
-
Is/if the motoplat original, sound like breakdown under revs. Put a PVL on if you have a mate with one handy, set at 2.3 btdc. Also clutch cable cable tied off wrong but looks good resto. Should of also mentioned that Coil should be earthed correctly and bare metal to frame. Maicos renowned for not running is not earthed correctly
-
beautiful looking resto by the way. Always wanted a Maico since Geoff Ballard came out here [nz] many years ago & made us all look silly [which i'm sure he could still do if he wanted]. Cheers.
-
Longshot, but the clip hasn't come off the needle?
-
I can't really add to what my learned friends have suggested but must say that I like your Maico a lot Martin. It's refreshing to see one without the billet bling, alloy swingarm and Wheelsmith stickers. I don't mind that kind of thing but lately it's becoming viral....it's just nice to see a clean stocker for a change.
-
It's the original motoplat, is the advancer in the secondary coil, so I could try to change just that?
The rotorkey is good.
The clip is on the needle.
Both enginecases and secondary coil has good bare ground, even used a bit of copperpaste to ensure it stays good.
Killswich is new.
Best thing would be to have a running bike and try on the carb or ignition from that to see, but it's the only one I know of in Norway...
AND THANK YOU ALL FOR ALL THE GOOD HELP, really apretiate (spelling?) it!!
-
Thanks Firko.
It has wide footpegs, new shocks, flatslide, renthal bars etc. But it still looks quite original doesn't it?
(exept the michelin-sticers, wich after looking at the pics, will come off again)
-
Your stand looks a bit precarious on that plush soft lawn. The grass is a clue that the photo wasn't taken in Australia ;D. The only change I'd make to your bike is to paint the pipe black as I reckon unpainted pipes start to look a tad shitty after a few rides. I had an bare metal pipe on mine until I gave up on trying to keep it nice and painted it.
-
I think it's an ignition problem even though it starts and runs up to part throttle,when the load comes on the capacitors and insulation on the coils commences to "leak or break down". Try another ignition and check the cabling to the kill button there could be a breakdown in insulation,also try it without the kill button connected up, it may be faulty even though it's new and passing enough voltage to ground to cause problems.
Good looking machine too,I think you're brave even getting on it,1/4 throttle would suit me I think!!
-
Left field!
check your reeds?
-
Reeds aren't working, in fact their not even in there... ;)
-
Not a Maico man but I thought the 490 I rode was reed,
Must have been the 500,
You have to forgive me it was 30 years ago
-
There are quite a few reed conversions around, probably rarer with a original pistonport nowdays, but it was only on factorybikes back then I think.. I think reeds came stock on 490 in 83? Not sure myself. :)
-
Back then a friend's brother was the Maico dealer,
We rode the same bush track, he allways had the latest Maicos
-
Change the Spark plug even though it is new... Easy check...
-
There are quite a few reed conversions around, probably rarer with a original pistonport nowdays, but it was only on factorybikes back then I think.. I think reeds came stock on 490 in 83? Not sure myself. :)
We got some reed valve 490s in mid 81 at our local dealer A&S performance in the UK
-
The 82 490 enduro came with a reed valve, it was still a twinshock bike and there are a few of those cylinders in use today.
-
Hook up a battery powered strobe if you are wondering about the advance.
Does a 2/stroke need advance anyhow ?
-
ignition
bing
wet plug after its running and stop must mean it getting fluid from some were .and were is it from cranckcase leaking or is it fuel because the ignition is faulty
if its a fault crank seal it would be leaning out when running/ sucking air
and if it sucking gear box oil you would think there was a new pope with the coloured smoke
-
had a 400 aw that did that
use to start wouldn't rev
faulty ignition
-
had a 400 aw that did that
use to start wouldn't rev
faulty ignition
I had one of my Motoplat ignitions do similar to this and it was a fault in the timing coil in the stator. Timing was good and stable at idle and low speed then just all over the place as revs increased. It caused at various times over heating, detonation, high speed miss and lack of power the problem slowly got worse. The motor never actually stopped but may as well have.
It was difficult to detect with a timing light as there was no consistency at all. It was found when Better Bikes put it on their test rig and ran at constant speed and mapped it.
-
Ok, thanks again. :) :)
It has new gasket and seals in the cases, so I'm at least hoping it's not there.
I have tried different setups on the carb, with no difference noted, so although the jetting may be off, I don't think that's the main issue.
Looks like I'm down to testing the ignition first.
And, it might be a 250 ignition, is that a problem? Just found our 490 and 250 run different ignitions?
-
same part number/ so im not sure never had a 250
250 400 490
169/ 3598 Motoplat Ignition Cpl 1 1 1