Vaughan

At first second correct 1981 175 carb did not fix it , I never went through this with either of the RD's i had . This bike has me baffled !! Same deal with this fresh carb that i very carefully went through,same have to kick and kick and kick like with other carb, when it finally cranks and warm it up it runs and revs out better now . When idling it doesn't want to idle smooth, if i set it at 1500 it skips between it and 2000 . Also same deal with air screw ,i can be at 1 1/2 and slowly close it completely and no effect at all , if i back out it eventually starts to idle down . This is the correct 81 carb , stock 150 main,upped to 27.5 pilot (stock 22.5) , stock needle and slide with clip at stock middle , air screw 1 1/2 to 2 turns. New NGK B8ES at .028 , fresh top end job , new prem. gas with marine Stabil , oil pump correct , tank is clean and petcock bowl and sock clean. Today i found it bogs if clip is second , cuts up at 4th or bottom and perfect in middle . Next the air screw , i tried 2 turns out at cold start and had to crank the idle screw way in to get to idle . Next after about 3 hour cool down i tried 1 turn out and this is the best this thing has ever run . It started 1st kick with full choke , i immediately took the choke off and it wanted to bog if i didn't feather the throttle. After it warmed up i rode around the neighborhood about 5 miles and ran the best it ever has . I'm going to try spray around the running flywheel , is propane better ? Also how can i test the coil ? Thanks !! I'm almost tempted to swap the 150 main with a 155 or 160 to see if if may help even more , it a tad sluggish and slight surge at times ?

Well no replys , we found a correct 1981 carb and going to build it when it shows up and hopefully be done with it to do another bike.

Thanks , had to sell the RD's and the 175 is one i'm doing for my buddy. May be doing a 75 175 for myself ?

Another awesome parts suppplier for Yamahas is Yambit's in the UK , Dave Newboult that runs it does an awesome job and great prices ! http://yambits.co.uk/parts_by_bike.php

Hey Sniff , very nice R5/RD .

Got a 25 and a 27.5 pilot coming. Never found a better PDF manual ,but you were definently right on the MK2 iggy and timing was OK . Have hunted up and down for a 3J1 00 carb body ,but looks like a dead end and he'll have to use the 78 125 one . Got my fingers crossed that bigger pilot and raising the float will fix it. Also may be buying a 75 DT175 for myself , $200 ,complete ,but pretty rough and does run.

Thanks for the help on the other forum. Got a 25 and a 27.5 pilot coming. Never found a better PDF manual ,but you were definently right on the MK2 iggy and timing was OK . Have hunted up and down for a 3J1 00 carb body ,but looks like a dead end and he'll have to use the 78 125 one . Got my fingers crossed that bigger pilot and raising the float will fix it. Also may be buying a 75 DT175 for myself , $200 ,complete ,but pretty rough and does run.

Hey guys, having a cold crank problem. 1981 DT175 , just had bored to 3rd over and installed a Yamaha Art piston and rings. New intake and gasket ,new NGK plug cap and B9ES at .028. The carb is from a 1978 DT125 (original one was butchered) , jetted mains to 175 spec (150) , pilot (22.5) and new slide and needle for this 1978 carb . The carb is spotless ( did clean emulsion tube) , first had needle clip in middle and now dropped to 4th which helped a little . Even when warmed up the air screw has no effect when turning in (even closed) . After kicking and playing with the choke about 10 kicks it cranks , after warms up it runs pretty good but could idle better. I set the float at 21mm (was higher and cranked a little better then) , one thing i had not checked is the timing and don't know how to with CDI . Thinking on resetting float to maybe 18mm which would raise it and wonder if pilot may be the problem ? Both carbs are 22.5 stock . Any ideas ? It really needs a correct carb body that i can't find ,Mikuni 3J1 00. Only PDF manual i found is the Clymer . Also i was told this has a MK2 ignition and the Clymer book is showing a MK1 . So my timing is good as in my pic ? Here's where it is now, Uploaded with ImageShack.us This is what Clymer shows for F,G and H model Uploaded with ImageShack.us Pick up coil's position now , Uploaded with ImageShack.us Pic shown in Clymer book , Uploaded with ImageShack.us

Hey guys been looking a good DT forum to help with the 81 DT175 i restored for my buddy . My past bikes were RD's a 75 350 and 76 400 . Hope i can find some good help and do same for you ! Uploaded with ImageShack.us Uploaded with ImageShack.us Uploaded with ImageShack.us