Migthy Mule Posted July 31, 2012 Share Posted July 31, 2012 hello all back again. Airhead has kindly posted me what I hope will sort out the steering bearing issue, so while I've been unable to put the front back together I took the opportunity to put the engine back in, but with mixed success, it fired up after a couple of kicks and I wound the throttle stop until it ticked over nicely but when I pushed the choke in the revs increased then wandered before the engine died, I whipped the plug out and there was a fair amount of oil on it. I have fitted a carb overhaul kit for the right year so Im going to check ive put it all together correctly. Still haven't sorted the auto lube so Im pre mixing at 35 : 1 - is this right ? I seem to be missing the exhaust gasket (one on way) could this cause this, fair bit of oil escaping from there to. In my experience the revs should drop when the choke is off, not sure how these carbs work, does it shut off some of the air flow or allow some extra fuel through, Thanks Link to comment Share on other sites More sharing options...
Moderator drewpy Posted July 31, 2012 Moderator Share Posted July 31, 2012 normally its an enrichment device, ie gives more fuel. is the auto lube still connected and giving extra oil? Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 auto lube disconnected and pluged I am right in thinking that choke on - is with it pulled out?, seems to be working in reverse Link to comment Share on other sites More sharing options...
Moderator drewpy Posted July 31, 2012 Moderator Share Posted July 31, 2012 out is on, at least it won't seize. did you put any non-standard stuff on the bike? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 31, 2012 Moderator Share Posted July 31, 2012 Best get the gasket ring in place first...pretty crittical on 2 strokes so we'll see how it is after that's fixed. Have you done any work on the engine...like replace the crank seals? You say you are premixing now, so have you capped off the spigot on the carb that was originially an oil feed? Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 out is on, at least it won't seize. yeah, I suppose too much is better than too little, fairly sure the bike is standard ish (actually about three bikes made in to one) but 175 head, exhaust, end can and carb should be correct, the air filter is in place and clean although the rubber manafold from airbox to carb is a bit of a frankenstein with self tappers and silicone - should be fairly air tight- is it possible the timeing could be out? not sure how to alter this I guess that the oil suggests too much fuel, It is a new plug and I had the generator re wound so spark should be good Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 Best get the gasket ring in place first...pretty crittical on 2 strokes so we'll see how it is after that's fixed. Have you done any work on the engine...like replace the crank seals? You say you are premixing now, so have you capped off the spigot on the carb that was originially an oil feed? Hi the engine had a full rebuild bottom to top but got someone with better skills than me to do it, bike was run on pre mix by previous owner, seems like a good seal if not very tidy sorry for my ignorance, I have always avoided 2 strokes cause im not a mechanic so trial an error seems to get me through with a 4 stroke engine, they just run badly if wrong but 2 strokes seem so fussy im sure they work by petrol oil and a little mystical magic Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 31, 2012 Moderator Share Posted July 31, 2012 auto lube disconnected and pluged I am right in thinking that choke on - is with it pulled out?, seems to be working in reverse yes choke is on when pulled out I disagree with your reasoning Sam, when a 2 stroke engine runs lean (air leak) it will race so pull the choke with this and it will enrich the mixture quite a lot so the revs will drop and settle more. Thats why I questioned the oil feed blanking and the exhaust gasket Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 Thanks, guess I should check the seal round the airbox then, and perhaps look at getting a new filter Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 Thinking back it had oversized jetting when overhauled the carb, this I suppose may have been to compensate for an air leak, thanks for posting me that yoke by the way, your a life saver. Filter looks clean to me but not sure if its correct, only seems held in place by the cover??? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 31, 2012 Moderator Share Posted July 31, 2012 no it will not be the seal at the airbox (though this needs to be good anyhow) its the seal to the inlet rubber you need to check and the seal from inlet rubber / reed cage / cylinder, try spraying with WD40 when the engine is racing (choke off) to see if it makes a difference Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 31, 2012 Moderator Share Posted July 31, 2012 Oversize jetting? be very cautious about downsizing, it may have been correct in the first place and downsizing can be catastrophic! what did it have, what does it now have, what exhaust, filter box intact and not drilled?? is it a mk1 or a mk2? Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 great, Ill try that tomorrow, dont think my neighbours will appreciate me starting it up now Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 It had a Minuni carb fitted 2H501 Needle Jet 2490 0-0 Main jet 160 Pilot Jet 25 on advice I bought an overhaul kit, I think from yambits correct to the year Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 I posted some photos of the exhaust in a previous post Cynic replied : ' looks like a gianelli pipe (common replacement for rotten stock pipe) with the generic tailpipe' no holes in the airbox other than the butchery that the previous owner used to attach the carb inlet rubber Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 31, 2012 Moderator Share Posted July 31, 2012 I wouldnt fit jets from yambits in mine, I prefer to stick with genuine mikuni jets, my mk1 has a Gianelli pipe and at the moment is running a 150 mikuni jet as opposed to the standard 130, the mk2 would run a 160 as standard and so with a gianelli would likely need a 170 (ish) can you really trust that a pattern jet is an exact match for a genuine one?...I couldnt and the risks are high Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 carb kit came from wemoto, I still have the original needle and jet, quick operation to swap back and try it, Ill also try that tomorrow, cheers Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 31, 2012 Moderator Share Posted July 31, 2012 yeah but get that exhaust gasket done as well Sam is the filter well oiled too, well oiled but not soaking...definitely not dry? Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 yeah will do, its in the postal system, if you are ever in Shrewsbury let me know, think I owe you a beer or two, thanks again Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 31, 2012 Moderator Share Posted July 31, 2012 just noticed it's a mk1 airbox, so would have had a 130 as standard, sou then yours would be similar to mine now with around a 150 jet with a Gianelli pipe (and an oiled filter) Link to comment Share on other sites More sharing options...
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