blackhat250 Posted October 8, 2012 Share Posted October 8, 2012 When I had my first DT back in the 70's I didnt know what a jet was, never mind where to find it! Happily rang that things neck for 1000's of miles without going near airbox or carb (or probably near the air filter either!!) but it never let me down. So your right, they're happy leaving all well alone! But if you don't!................... . Definatly , but when you inherit these bike now, most have been tampered with, good post this, Link to comment Share on other sites More sharing options...
flyday58 Posted October 8, 2012 Author Share Posted October 8, 2012 When I had my first DT back in the 70's I didnt know what a jet was, never mind where to find it! Happily rang that things neck for 1000's of miles without going near airbox or carb (or probably near the air filter either!!) but it never let me down. OemParts#/Yamaha/DT175E_-_1978/INTAKE/DT175E_(1978_MOTORCYCLE)/INTAKE_(DT175E_-_1978) Also agree, so I have to believe the formulation of the petrol available today has alot to do with our issues. I never had a prob back in the day, thought a jet was the thing I wanted to fly one day. Anyway. V, my airbox is this jewel: The bit I installed then removed is #23. I am currently caught in the Relations Matrix: something is wrong, alternately or sometimes simultaneously, with my wife; son; daughters; father-in-law; mother-in-law. I have hardly had time to myself, except when at work. I really want to thoroughly map out different set-ups on the DT but, as I've said elsewhere: I run and I run to catch up with the sun, but it's sinking... Link to comment Share on other sites More sharing options...
Ventura Posted October 9, 2012 Share Posted October 9, 2012 The differing airboxes are certainly a little puzzling!! I notice the 1979 175F airbox doesnt even include your No23 "suction pipe"........... And then when you look at my '79 175MX it has this convoluted arrangement, which I assume is only to reduce induction noise (which cant be heard over everything else anyway) and to make the air as dizzy as possible before it reaches the filter!!......... When you look at the cover which goes over that then no wonder that little rectangular entry is such a restriction!..... (I think the additional round hole is not standard and was drilled by a PO?) I'd be inclined to remove the whole lot but as Im striving to keep the bike as original as possible, and also that its performing and riding so well now, I think I'll leave it all as it is and just enjoy what I have :D V. Link to comment Share on other sites More sharing options...
flyday58 Posted October 9, 2012 Author Share Posted October 9, 2012 It's a wonder that there were such big differences between country requirements even back in the good old 70s. Here's my airbox without: and with the snorkel: reverse angle: Intake was already this small: Then the snorkel cut it down to this: Not much breathing room here. Would seem to make things overly rich. Link to comment Share on other sites More sharing options...
dt502001 Posted October 10, 2012 Share Posted October 10, 2012 I have been folowing this for a while and what it all boils down to is DBA's the USA were more forgiving on noise than the UK ,so yam up the intake a we bit by puting the snorkel on and hence givin a small% of more air to the box. The bikes that came to canada had way bigger holes..nobody gave a flying f about db's then here, most bike imported to the USA had to meet caliafornia rules which were very strict then and even more now. Hell in some parts of Canada you can still pull a car or bike out of a field and if you can get it running ..wel than drive it.... no ?? asked. If a bike cant meet 82 dba in cali and lot of other states it's not road worhty by law,,hahaha ask any hardly rider if his bike meet that rule NOT likely. And the test must be done in 2nd gear at @ 40 or some stupid thing like that so that includes exhaust and intake noise.You might not hear it on the bike but it is making noise. Open the box up with a 2.1/2inch hole saw and Hook up a wide band and,, re jet the bike,,, if you guys want to look hard enough the bikes came here with way biger air intakes and a rubber to stop water from gettin in,in deep water. Just looking at the picts you guys have posted I know ours were way bigger. And guys were still drilling hole's in the box top As a matter of fact I remember years ago at the trac someone pulled that snorkel off for a guy and he was way happier after Link to comment Share on other sites More sharing options...
Moderator Cynic Posted October 10, 2012 Moderator Share Posted October 10, 2012 So my airbox is what you lot are dreaming of... And the reason the 1980 on uk mx goes like shit off a stick. Making a shitload of noise inthe process. Leave the lid off and your ears hurt. Even wuth a full face lid. Neighbours love me at 4am.........hey ho she's legal.... http://www.cmsnl.com/yamaha-dt175h-1981_model8795/partslist/A-11.html Link to comment Share on other sites More sharing options...
flyday58 Posted October 10, 2012 Author Share Posted October 10, 2012 So my airbox is what you lot are dreaming of... And the reason the 1980 on uk mx goes like shit off a stick. Making a shitload of noise inthe process. Leave the lid off and your ears hurt. Even wuth a full face lid. Neighbours love me at 4am.........hey ho she's legal.... http://www.cmsnl.com...slist/A-11.html Yeah, accidently misplaced my filter last night, (oops) and the pep was quite evident. Right up to the point at which it seized. Again. Link to comment Share on other sites More sharing options...
flyday58 Posted October 26, 2012 Author Share Posted October 26, 2012 Somebody slap me. Please. Decided to take the heavy coat of hi-temp paint off the cylinder and head to see if it would lower my temps any. Upon removal of same found the piston varnished, four scribe marks aligned with the cylinder ports down the skirt. I figured it was time for a good autumn tear-down, so off I went. The oil only had about 50 miles on it, but smelled like 5000. Hmm, me sez to meself. There was also a good helping of mud and goo in the bottom of the case, also reeking of exhaust fumes. Hmm, me sez again. And a nagging thought slowly rises as I continue. A thought which had occurred to me before, but in the interest of continued good times and letting them roll I was content to put out of mind. Ya see, while I purchased both crank seals, I never made the down time to open up the clutch-side case to replace the right side seal. When I removed it I found the inward-facing spring broken, the seal surface cut. So exhaust was blowing into the case, dirty air was getting sucked in, leaning the mixture. I probably added fuel to the fire with the bigger main jet, allowing the thing to cook hotter and hotter. So the DT mill is in boxes awaiting parts. Will be replacing the crank bearing to rid meself of that nasty harmonic vibe that was getting stronger of late. Wife absconded with the camera but I will post a pic or two when she gets home with it. On the plus side, the CS5 runs very perky so have been out on it a bit. Will be at the Red Lion in Langley Saturday after 4 if anyone local wants to come and slap the out of me. (not really Cockney rhyming slang but I'm USian...) Link to comment Share on other sites More sharing options...
flyday58 Posted October 26, 2012 Author Share Posted October 26, 2012 Link to comment Share on other sites More sharing options...
flyday58 Posted December 19, 2012 Author Share Posted December 19, 2012 FINALLY got my parts, going back together AGAIN. Link to comment Share on other sites More sharing options...
flyday58 Posted December 19, 2012 Author Share Posted December 19, 2012 New bearings, seals, a better crank - the original spent some years in a wrecking yard with typical rain results. The left side case and magneto spindle on the crank suffered the most damage, lots of pitting possibly preventing a good seal, so I put in my spare, along with the left case. Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted December 19, 2012 Moderator Share Posted December 19, 2012 Ohhhhhhhhhhhhhh, naked engines. 1 Link to comment Share on other sites More sharing options...
Moderator Airhead Posted December 19, 2012 Moderator Share Posted December 19, 2012 nice one flyday, in the crank pic.. .wheres the 'O' ring? Why does the taper look so manky? is there some broken material in the keyway? Link to comment Share on other sites More sharing options...
flyday58 Posted December 19, 2012 Author Share Posted December 19, 2012 Link to comment Share on other sites More sharing options...
flyday58 Posted December 19, 2012 Author Share Posted December 19, 2012 Ohhhhhhhhhhhhhh, naked engines. You're such a perv, DDT! Ain't we all! (Except for maybe Sacha...nah!!) Link to comment Share on other sites More sharing options...
flyday58 Posted December 19, 2012 Author Share Posted December 19, 2012 Pics are 3 days' worth of work last week. Felt good to be doing some assembly again. Once a mech, always a mech, I guess. Link to comment Share on other sites More sharing options...
flyday58 Posted December 19, 2012 Author Share Posted December 19, 2012 Link to comment Share on other sites More sharing options...
flyday58 Posted December 19, 2012 Author Share Posted December 19, 2012 You can see the water damage on the clutch pressure plate. I ended up replacing it as I had to disassembled the whole thing again for reasons I will not here divulge. Let's just say I felt a right arse when the shift shaft wouldn't slide through the bore. Link to comment Share on other sites More sharing options...
flyday58 Posted December 19, 2012 Author Share Posted December 19, 2012 Yes, the washer for the tacho gear IS installed... Ready to dance. Almost. Link to comment Share on other sites More sharing options...
flyday58 Posted December 19, 2012 Author Share Posted December 19, 2012 Nothing says 'love' like Mikuni! Link to comment Share on other sites More sharing options...
Recommended Posts