RZ/RD 350 & Misc. 2-Stroke Tech BBS

Technical Forums for Two-Stroke Nuts
It is currently Mon Aug 21, 2017 5:51 am

All times are UTC - 4 hours [ DST ]




Post new topic Reply to topic  [ 17 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: Mon Jun 19, 2017 12:55 am 
Offline
-----
-----

Joined: Sat Feb 08, 2014 5:39 pm
Posts: 853
Location: Vancouver Is. Canada
Was about to fire up the bike after dealing with timing adjustment but it won't kick over. Prior to kick over, replaced both carb needle seats and needles (fuel was leaking out the drain lines) , tested the carb floats would float - working, set both float levels @ 21mm at 60 degree tilt, set the carb slide dimple in the centre of the carb glass sites & balanced the carb slides with popicycle sticks. Pulled out the plugs - both spark is blue/white and gapped to spec. Put a 5mls of fuel in each pistion and tightened in the spark plugs. Fired up 1st kick and 2nd kick but just died after the fuel was depleted. Kicked the engine over about 6 time throttle wide open - nothing. Ck'd the plug again and both appeared dryish. It appears to me the carbs are the issue. Pulled the carbs apart again and ck'd the main and pilot jets with compressed air - both had flow. Had th carbs cleaned them last year and drained the bowls . Dirty carb channels perhaps?


Top
 Profile  
Reply with quote  
 Post subject: Re: Mystery carbs
PostPosted: Mon Jun 19, 2017 1:03 am 
Offline

Joined: Mon Mar 03, 2014 8:44 pm
Posts: 2281
Location: Calgary, Alberta, Canada
Pull out the pilots and see if they are plugged.

Also, the Popsicle method only sets the sync of the carbs mechanically. It does not consider the different vacuum rates of each cylinder. Unisyn is needed for that.

Choke should be on, no throttle.

Not kicking over means seized. Not firing up when kicked over is a different story.

_________________
Rory


Top
 Profile  
Reply with quote  
PostPosted: Mon Jun 19, 2017 1:38 am 
Offline
-----
-----

Joined: Sat Feb 08, 2014 5:39 pm
Posts: 853
Location: Vancouver Is. Canada
Both pilots are clear - ck'ed with a light. Also ck'd the reeds to see if they were opening - functional. Just one unisyc required?


Top
 Profile  
Reply with quote  
PostPosted: Mon Jun 19, 2017 1:43 am 
Offline

Joined: Mon Mar 03, 2014 8:44 pm
Posts: 2281
Location: Calgary, Alberta, Canada
Yes, you move it from carb to carb, with no filters or boots. You'll need that when it's running. About $80 delivered off e-bay.

Plugs are new?

Do you have gas flow out of the petcock?

_________________
Rory


Top
 Profile  
Reply with quote  
PostPosted: Mon Jun 19, 2017 1:58 am 
Offline
-----
-----

Joined: Sat Feb 08, 2014 5:39 pm
Posts: 853
Location: Vancouver Is. Canada
Plugs are new and there is flow fm the tank to the carbs. Unscrewed to the drain screw and had flow. Learnt that I can purchase the unisync from my local Lordco. Will use it once it running again. Perhaps its a vacuum leak near the reed boots that prevents draw into the combustion chambers.


Top
 Profile  
Reply with quote  
PostPosted: Mon Jun 19, 2017 3:35 am 
Offline

Joined: Mon Mar 03, 2014 8:44 pm
Posts: 2281
Location: Calgary, Alberta, Canada
Is the gas all new, or was it mixed with old?

_________________
Rory


Top
 Profile  
Reply with quote  
PostPosted: Mon Jun 19, 2017 6:00 am 
Offline

Joined: Sun Sep 16, 2012 7:10 am
Posts: 156
Location: gold coast Australia
is the fuel transfer pipe between the left and right carb installed? (part number 30 in service manual). I found my bike would not start without it. Also check you have float bowls installed on the correct carb. they are different from each other.

_________________
yamaha fanatic. bikes, 1984 stock rz350. 1983 rz350 race bike 34.5 mikuni, zegers cylinders, chambers 1985 rz250, 1988 rz250r, 69 yl3 100cc , 87- tzr250, 67- yas1 125, 67 yr1 350. 67 ym2 305. 77 dt175. 2000, Yzf1000r ace, 79 xs750f, 2001 wr426 2016 R1.


Top
 Profile  
Reply with quote  
PostPosted: Tue Jun 20, 2017 12:58 am 
Offline
-----
-----

Joined: Sat Feb 08, 2014 5:39 pm
Posts: 853
Location: Vancouver Is. Canada
Gas is a mth old when mixed. The transfer pipe is/was connected. What the differentiation between the float bowls (choke vs. non choke carb) - the exterior joining pattern half way up the bowl Graham?


Top
 Profile  
Reply with quote  
PostPosted: Tue Jun 20, 2017 1:47 pm 
Offline

Joined: Sat Nov 26, 2005 11:44 am
Posts: 352
Location: Wolfenbüttel, Germany
Sounds a bit like swapped float bowls.
Unfortunately they cannot be distinguished from the outer shape, so get the carbs off once again and check if the left one has the choke jet at the bottom of the appropriate passage.

_________________
Bye
Martin


Top
 Profile  
Reply with quote  
PostPosted: Tue Jun 20, 2017 9:08 pm 
Offline
User avatar

Joined: Sat Oct 10, 2009 4:33 am
Posts: 9141
Location: Sydney
after many years the inner passages get gummed up, people drill the brass balls out and replace them after. 4.5mm brass balls is what you need, drill 3mm hole and use either a tap and bolt or a self tapper to remove, hammer new ones in after.

_________________
My Projects:
Yamaha '85 RZ350 F1 & '83 RZ & RD Athena 421 LC & XT500 Supermoto & Honda MT250... See them all on www.2smoked.com

Like Watches? You will love www.PloProf.com & www.DeskDivers.com


Top
 Profile  
Reply with quote  
PostPosted: Wed Jun 21, 2017 2:38 am 
Offline
-----
-----

Joined: Sat Feb 08, 2014 5:39 pm
Posts: 853
Location: Vancouver Is. Canada
I suspect Redman412 is having the same issue as myself. So, pulled out the bowls and photographed them from the bottom. Which is left or right? The only marking I note are the numbers on the top of the bowls. Yes, I'm aware one is brass but that's what was in one set of carbs. I'm wondering if I should just by a new OEM set (assuming they will arrive left/right).


Attachments:
IMG_3677.JPG
IMG_3677.JPG [ 123.89 KiB | Viewed 459 times ]
IMG_3678.JPG
IMG_3678.JPG [ 75.22 KiB | Viewed 459 times ]
IMG_3679.JPG
IMG_3679.JPG [ 66.87 KiB | Viewed 459 times ]
Top
 Profile  
Reply with quote  
PostPosted: Wed Jun 21, 2017 6:34 am 
Offline

Joined: Fri Dec 28, 2012 9:23 pm
Posts: 342
Location: Quincy, FL USA
Now I am confused. The float bowls are what get swapped, not the floats!

_________________
Red/White US '84, Spec II pipes, Y-boot w/K&N, Fox Shock, Mikuni carbs?


Top
 Profile  
Reply with quote  
PostPosted: Wed Jun 21, 2017 6:34 am 
Offline

Joined: Sun Sep 16, 2012 7:10 am
Posts: 156
Location: gold coast Australia
Floats are the same. It is the float bowls that are different the left hand bowl has a hole in the pick up tube to recieve fuel when you pull the choke. The righy carb has the tube but it doesn't have a hole in it. Hope this explains it for you. some times it can get blocked. i fould a thin guitar string can clean it out. you should be a ble to suck air through it.
.

Sent from my SM-G900I using Tapatalk

_________________
yamaha fanatic. bikes, 1984 stock rz350. 1983 rz350 race bike 34.5 mikuni, zegers cylinders, chambers 1985 rz250, 1988 rz250r, 69 yl3 100cc , 87- tzr250, 67- yas1 125, 67 yr1 350. 67 ym2 305. 77 dt175. 2000, Yzf1000r ace, 79 xs750f, 2001 wr426 2016 R1.


Last edited by graham heise on Wed Jun 21, 2017 6:40 am, edited 2 times in total.

Top
 Profile  
Reply with quote  
PostPosted: Wed Jun 21, 2017 6:35 am 
Offline

Joined: Sun Sep 16, 2012 7:10 am
Posts: 156
Location: gold coast Australia
Image Image Image

Sent from my SM-G900I using Tapatalk

_________________
yamaha fanatic. bikes, 1984 stock rz350. 1983 rz350 race bike 34.5 mikuni, zegers cylinders, chambers 1985 rz250, 1988 rz250r, 69 yl3 100cc , 87- tzr250, 67- yas1 125, 67 yr1 350. 67 ym2 305. 77 dt175. 2000, Yzf1000r ace, 79 xs750f, 2001 wr426 2016 R1.


Top
 Profile  
Reply with quote  
PostPosted: Thu Jun 22, 2017 1:17 am 
Offline
-----
-----

Joined: Sat Feb 08, 2014 5:39 pm
Posts: 853
Location: Vancouver Is. Canada
Cheers Graham for info not in the manual. Ck'd all 6 carbs I have in stock only one set had the proper left choke float bowl and it was the set on the bike properly arranged. My next step is to replace the pilot jets with brand spanking new ones after I sonic clean both carbs.


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 17 posts ]  Go to page 1, 2  Next

All times are UTC - 4 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 7 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group