jbhome

well, I finally got it running well but now the rear shock is too soft. I'm 175Lb and it's way too easy to bottom. anyone have any suggestions on rebuild replace? thanks, Jim

Well I thought I was done. This is regarding the kickstart not disengaging. The picture above doesn't show the parts behind the gear. There is a lobe on the shaft the limits the travel of the shaft (foot off kickstart /foot and kickstart at lowest position). There is also a large spring clip that should ride in a groove on the back of the gear on mounted on the kickstart shaft. In my case this came off/moved and was sitting between the gear and the case limiting the gear's ability to clear the clutch gear. The spring clip, slides on the gear but... has enough friction when you kick, to stop the drive gear from turning. This in turn causes the gear to run up the spline on the kickstart shaft and engage the clutch gear and start the engine. In my case, there was not enough tension on the spring so a little bending was required to ensure it properly engaged the gears. It would sure be nice if there were pictures of this. I have a service manual that has phrases like install and remove. I for one expect a little more from a manual. It's kind of like putting an open door sticker on a locked door to a room. I know I want to open the door. The question is how. So much for my rant. On step closer to being done.

ok finally it works. first comment ... Never assume. I assumed the bike was in factory state....WRONG as noted earlier, oil seal in oil pump blown oil o/p line connected to float bowl overflow fitting throttle slide hose connected to oil input fitting on carb main jet needle clip set 1 down from normal/center position air cleaner backwards in box. This was the last issue the bike now revs freely, doesn't smoke and pulls like a champ Never assume. now maybe I can get a ride in before the white stuff comes and clean it up over the winter. thanks everyone for your help, and patience in resurrecting my new ride jim

what's the best way to do that. I took off the intake manifold and chkd the reeds. They looked ok but the gasket was toast. I made a new one and used grease on if rather than gasket goo. Will the rubberized side seal to the carb fitting?

Hi mod, Thought I did but will check. update on starting. starts first kick on choke but as it warms, there is no idle. Keeping it around 4-5k will keep it running but release throttle and it dies. haven't replaced o-ring on idle mix adjust needle but would expect that to move adjust setting at most. guess I get to pull that apart again too. Arrggh would like one ride fore it snows.

Thanks for the responses. Hopefully this clears the problem. I replaced both crank seals and in the process, had to pull out and re-install the kickstart shaft. Now when/if the bike starts, I get a ratcheting sound from it even though the lever is all the way up. what am I missing? jim

He's back. Rather be riding but... When I got the bike, there was a tube going from a fitting on the side of the carb in line with the slide, to a second fitting at the lower front/engine side of the carb. Both fittings are on the side opposite the choke pull. There was a third fitting with a tube going to the oil pump. Seemed correct but now I'm not so sure. In thinking about it, isn't the bottom fitting on the float bowl the overflow, and shouldn't it just go back between engine and frame. The fitting nearest the cylinder would seem a logical place for the oil fitting, leaving the one on the throttle slide??? With hoses fitted as originally purchased, the bike starts, idle picks up then engine dies. I plugged the end of the tube going to the engine side of the carb (vs air cleaner side) and connected the line from the oil pump to the fitting on the throttle slide and things worked better but still not right. Haven't been able to find any pictures of this area nor is there any good detail in the parts schematics. Regards, Jim

thanks for the quick reply everyone. I did the cloth thing with the crank bolt but I'm still unclear about the clutch nut as the basket is now free. I would like nut torque specs if possible as well on another note, I'm broken hearted. The last bit from my impact tool bought when I had 71 ct175 broke. The tip just gave op. sniff. Small tear down cheek. so good at undoing those challenging map Phillips screws. now to find new bits in I can order that. For you land.

Well I guess I'm back again just chaulk full questions. I'm replacing the clutch side crank seal and not sure how to disconnect the oil line from the clutch side cover to the oil tank. any suggestions gratefully accepted. I got the inner clutch basket retaining bolt off with my impact wrench but not sure how to torque it back on as I don't have the appropriate wrench. on the same note what's the best way to bend the locking plate up to secure the nut? let's hope it runs ok after this. After sitting for a couple of days it starts right up with a fair amount of smoke??? As the pump is disconnected runs for a while and then dies. have a great day/ride Jim 92 FJ 79 DT175 73 CT90 2012 raspberrie pi 2012 Mendel prusa.

I would if the fund said yes. Right now it is saying no no no. I had noticed a small red puddle developing under the bike so I decided to have a look at the oil pump. It looks good, all nice and shiny. The gush of oil and ??? something that didn't mix with the oil.. water??? was impressive. When I took the pump off, I found the seal most of the way out of the pump. Guess that would explain the drip and full cavity. I'm wondering if having the pump open like that might have contributed to the weird operation of the engine, drawing air through the pump, into the oil feed channel into the carb??? BTW how does one take the hoses off? The one with the spring clamp was easy. The other seems to have a tubular clamp and didn't seem real interested in coming off. Jim Doing a teardown at a more modest pace.

Well.... I'm back again. Got a flywheel side crank seal and replaced it. I pushed the seal in a bit far, expecting a sholder so it's about 70 mm below the case shoulder. Should have read the post above but that's how it goes. I smeared some grease on the both inner and outer seal faces as well as the OD of the seal. The bike started almost immediately. Idle was a bit unsteady. Tried to ride it and as soon as I let the clutch out/load the engine,it started to baff and wanted to stall. I have not done the clutch side seal yet. If I let it sit for a minute or two, it starts first/second kick, idles for a couple of seconds, then dies. Reving it seems to keep it running. Pulled the plug the first time and it was wet. Second time not. The oil light is on but it's smoking a reasonable amount so not going there just yet. Any sage advise greatfully accepted. Jim

yep some people do have a lot of time and we are so lucky to benefit from their dedication. compares well to the Honda dominoes add.

Maybe the spark was a finger problem or maybe my old eyes couldn't see it in the bright lights. All of the connections looked fine and the signals from the trigger coils seem to be reasonable. It started with the old black plug originally then stopped don't know. It's working. When I sprayed wd40 into the area behind the flywheel, it started immediately, ran for a few seconds and died so I'll order seals tomorrow. The white stuff is not in chunks like some of the pictures I've seen it's just a powdery deposit in the bowl and lower carb body. It's probably OK.

Re the spark issue. It had little/no spark so I started there. Pulled/reseated all connectors, went through the ohms test above. Net result I get a nice blue spark. Re the flywheel puller, I lucked out and bought one for a Suzuki and it fit perfectly. I Just happen to have an electric impact driver and taking the flywheel off was a breeze. Torqueing is a little more difficult as I don't have the flywheel holder but fifth gear a friend and lots brake seems to work. Re the clutch side I've used a rag between the crank/clutch gear. Seems to work well enough. Re crank bearings, the engine sound good when it's running. No rattles or vibes so for now it's just seals, assuming the flywheel side is not corroded too much. I'd still like a way to remove the white deposits(aluminium oxide?) from the carb. Any suggestions. Re parts list, I've been using the Yamaha OEM websites with exploded views. Do you have something you could share? So we're OK with the spark issue? Seems my lot in life to piss people off without even realizing it. Remember. The shiny side goes up! Jim

Welll...... The seals have it. Sprayed wd40 around crank and it started and ran for a couple of seconds then died. Thanks for the hints. Are seals hard to find? What is the best/safest way short of case splitting to remove the seals.? Watched a guy on youtube punch/crease in the metal edge of the seal(releave pressure then worked on a screwdriver to lever it out? Old plug looks pretty black so I guess both seals would be appropriate. Again everyone, thanks for your help and your patience. Have a great ride Jim

Ok some progress. I have a blue spark. Took carb off and re-cleaned, removed emulsion tube and cleaned squirted carb cleaner everywhere, Blew the heck out of everywhere and put it back together. Started then stopped again. Kicked for a while. Plug is dry... The inside of the carb has a white residue on everything. not thick. What can I use to get rid of this. Even with the carb clearner once it evaporates, the white deposits show up. BTW what is the best way to remove/install the carb? I've been loosening the cylinder head clamp and the air box clamp and leaving the rear boot on the carb but I'm concerned about the stress when I put the carb in. Would a blown crank seal do any of this? It seemed like it was going to run ok cept the rubber plug on the side of the carb had fallen off and I stopped it to put the cap back on. Argggh! Thanks, Jim

wishfull thinking? Paid $120 for an official Yamaha manual for my th only to receive a photocopy of a photocopy. Barely legible. I get the point though. My local Yamaha dealer fax the schematic and with your help and some research I've figured out the wiring. Kicking the engine over, I get about 4V P-P one red and white red. Ohms from the coils at the first connectors are correct for magneto power but not the pulse lines, however the voltage from them seems to be reasonable. I'm rechecking at the CDI connector now. Again things look normal. Given I see 10's of volts from magnetron power but volts at the orange coil line seems like the cdi is bad Jim BTW I give up with the spelling. My #$% tablet keeps changing so please bare me. Again, thanks loads for the help, Jim

Thanks Airhead. I'll check that out today. Some further details. When I first tried the bike it started and reved probable to redline sticky throttle. Checked slide/cable ok so tried again. Started, idled so off I went. Pulled strong in 1, 2, 3 then started to bog like fouled plug or out of gas. after that, no even a pop when I kick. On a side note found this link www.transmic.net/en/analog.htm. Looks like a good alternative to the used CDI'S on ebay. This so reminds me of my ct175. Intermittent dead. Turned out the points wire coming out of coil passed through coil frame. Vibration wore insulation away and shorted out wire. That took a while to find. Thanks again for your help and your patience. on another note. At 33 years, are the copyrights for the Yamaha manuals not expired? Seems like they should be in the public domain by now. Just my thought and you know what that is worth. Jim BTW did I tell you how much I hate auto correction?

Hello all, Well after too many years, (had a CT1 that was almost new) I just bought a 79 Dt175. Started first kick at sellers house, then died like out of gas, but it had gas ( very old). cleaned carb, replaced gas but no vroom. Tank off checked all connections, battery 6.0V but little or no spark at plug. Metered trigger line to coil and see a pulse when I kick it. On/off switch working. I think the ignition switch kill circuit is in parallel with the on/off switch so I'm assuming him switch works. metered the coil from the common wire to trigger wire, and plug lead and seem ok though I don't know what value range is good. Does anyone have more detail on the did system wiring. What wires do what. Does the does the did system require the battery. Any hints on testing the did unit? Sorry for all the A's but the days are getting shorter and I've yet to turn a wheel. Thanks in advance for any and all help and suggestions. Have a great summer, Jim Brooks

Hello all, just bought a 79 DT1 with 9000k. Started first kick and ran strong but... Shades of my CT1. Both would stall for no apparent reason. After half an hour of kicking it would star and run fine till the next time. The DT1 doesn't start. Little or no spark so now the research begins. It looks/felt good while it was running so should be fun. Any suggestions gratefully accepted. It's getting fuel. Battery is 6V. Kill switch is working both on and off. From the schematic, it seems the ignition switch also acts like a kill switch so I believe that part is working. When I put a meter on the (points) side I know there are no points, its just to I'd the wire, and kick, I get a pulse out of this wire. Does anyone know/have more details on the CDI circuit? Have a great ride, Jim Brooks