DT175 1978 Posted October 5, 2012 Share Posted October 5, 2012 Do I have to remove the cylinder head and cylinder to check / change the reed valve? My Clymer manual tells that step #1 is to remove the cylinder head and cylinder and I cannot figure out why that would be necessary at all. Link to comment Share on other sites More sharing options...
nayruf Posted October 5, 2012 Share Posted October 5, 2012 Hi The engine on my little bike is similar and to get at the reeds all I do is remove the manifold bolts slacken off the front, rear air cleaner and intake hose clips, turn off the petrol tap and disconnect the fuel and oil pipes, I don’t even have to undo the throttle cable as I can ease the carburettor out of the air cleaner hose and manifold hose letting it hang out of the way on the cable, all the breather pipes stay attached to the carb and only need feeding back on the re-fit ,I believe your bike has about the same access so I see no reason why you cannot do the same, Link to comment Share on other sites More sharing options...
DT175 1978 Posted October 5, 2012 Author Share Posted October 5, 2012 Thank you. I agree - I'm sure I'll physically have no problem removing the reed valve assembly with the cylinder head on the bike. I don't know why the manual says that. The only reason I could think that they might say to do that is if it's just catagorically unsafe to remove / install the reed valve because you might allow dirt and grime inside the cylnder? But, I'm with you - I see no reason and I'd really rather not have to remove the head to do reed valves. (the same manual says under carberator removal that step #1 is to remove seat, tank, and side plastics - none of which are actually necesary for removing the carb, so maybe it's justthat same kind of thing...) AS a side note, I've - I have a poor running bike. I've had a hard time describing exactly what's wrong, but I've been googling crank seal symptoms and reed valve symptoms... The way my bike runs doesn't exactly bad crank seals, but it sounds to me exactly how they describe bad reed valves, so I better get serious about replacing reeds. Thanks. Link to comment Share on other sites More sharing options...
flyday58 Posted October 6, 2012 Share Posted October 6, 2012 On mine the carb won't come out without partially removing the air cleaner assembly. The old air cleaner and carb joints aren't flexible enough to just yank it out. So it's remove the 2 air cleaner bolts, pull the box out of the keeper under the battery and work the box out far enough to get the rear of the carb out. Then the carb comes out easily enough. 4 bolts and the reeds are out and I agree, no sane reason for removing the cylinder. Having the tank off improves visibility but also not necessary. Re your related thread, did you ever check the resistance of your coils, and did you try the spray-check of the left-hand crank seal behind the magneto? Unless the reeds are obviously damaged, bent, rusted through or missing, your poor running probably won't be caused by them. But in the interest of being thorough it won't hurt to check them. Link to comment Share on other sites More sharing options...
DT175 1978 Posted October 6, 2012 Author Share Posted October 6, 2012 Thanks Flyday Re your related thread, did you ever check the resistance of your coils, and did you try the spray-check of the left-hand crank seal behind the magneto? Unless the reeds are obviously damaged, bent, rusted through or missing, your poor running probably won't be caused by them. But in the interest of being thorough it won't hurt to check them. Thanks Flyday Not yet - I have an new air cleaner element coming in two or three days, my old one is very nasty, and I didn't want to move on until I get a new one installed. (had to wait for a payday to order it, now waiting for delivery) I'm going slow, one thing at a time, because I'm a bit inexperienced but I'm learning every step of the way. Once I have the new air filter on, I plan to play with carb adjustment a little bit more before moving on. I'm also going to take my new reproduction carb apart and look for asembly errors, just to make sure I'm satisfied with it. Then I should be satsified with fuel, tank, petcock, carb, air cleaner, spark plug, and ready to move on. (might get a float bowl gasket and rebuild the original carb too - I have it all apart and it just needs cleaned and put back together) Then I'm going to try that spray check on my left hand crank seal - you recomend carb cleaner or WD40 for that? I think I should also spray check around the intake manifold / boot and really check out it's condition, make sure it's not leaking. My carb comes off easy enough by just backing off the screws on the clamps, then pushing it back toward the air box, turning it a bit to get the front part out of the notch, then I can get the front part out and take it right off. Okay, it's a twisting, tugging, wrestling match. I was figuring I'd check the manifold and reed valve out when I have the carb off for inspection. SO - I think I need a gasket kit. I want to have a new reed valve gasket in hand before yanking it out..... AND - I've never had the engine side covers off. I need gaskets for the side cover too, don't I? Or do I - I can see reusing the old ones if thy're not bad... Might as well get the full kit before ripping into it...just in case... do those engine gasket kits come with a float bowl gasket for the carb? (I don't think they do)... I'll probably have some questions when I get electrical / resistance testing... like what all to check (igniotion coil, and... the coils in the magneto?) ONE MORE question for now - Do I need an impact driver to take the side covers off the engine? My Clymer manual says it is not advisable to do it without an impact driver. I've been waiting for impact driver and new gaskets before I take the side covers off - Am I being silly? My family wanted something to get me for my upcoming birthday, so I am expecting a torque wrench and an impact driver as gifts within the next few weeks! I should be able to do a lot more! Link to comment Share on other sites More sharing options...
flyday58 Posted October 8, 2012 Share Posted October 8, 2012 Use WD40 or a similar oil-based spray on the crank seal while the engine is running. You want something that will temporarily close any gaps between the crank boss and the seal that might be allowing air to be sucked in, thinning the mixture. If the engine speed changes while spraying, the seal is shot. The gaskets for the side covers will probably be semi-welded in place, and usually to alternate sides so that part of it stays with the engine case and the other part sticks to the cover. Careful scraping it off so as not to gouge the casing or cover surfaces. Carb bowl gaskets sold seperately. Impact driver is a must-have, along with a torque wrench. I don't own a torque wrench, I'm an American Idiot (cue Green Day ) Link to comment Share on other sites More sharing options...
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