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Author Topic: '84 SR250 Garage build.  (Read 17599 times)

Offline kopcicle

  • Posts: 708
  • antidisestablishmentarian
Re: '84 SR250 Garage build. Solo Tracker now, Cafe later.
« Reply #20 on: Apr 29, 2013, 03:40:21 »
http://www.dotheton.com/forum/index.php?topic=24283.msg259348#msg259348

might be some help btw use the viton O-ring  and NOT the Buna- N .

~kop
"If a man wants to carry two cats home by their tails, by all means let him. He’ll learn things that he might not have otherwise even guessed, and the experience will be one he’ll not soon forget!"

~S. Clemens

If it leaks after all this? I'm gonna pull a "Brad" and bulldoze the fucker!

Quote from: Scruffy;1025553
As an equal opportunity bigot, I'll insult any brand, any style, any time...:wink:
-Scruffy

http://tinyurl.com/TheRedBike

Redliner: me? But I'm not a little girl any more
Nov 13, 2013, 19:20:58

Offline Brodie

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  • Posts: 2064
  • Gold Coast, Queensland
Re: '84 SR250 Garage build. Solo Tracker now, Cafe later.
« Reply #21 on: Apr 29, 2013, 03:44:17 »
Thanks Kop, I will give that a read now while I wait for the chemicals to do their job.

As for the O-ring I didn't even know there were different types. I have a lot to learn yet. Thanks.

Offline Brodie

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Re: '84 SR250 Garage build. Solo Tracker now, Cafe later.
« Reply #22 on: Apr 29, 2013, 04:00:36 »
All to often the novice will attempt to make up for other causes of flooding by bending the tab down onto the needle valve so far that no fuel will leak but also no fuel will flow . A general rule of thumb is if when upside down and the float adjustment tab is just resting on the needle valve adjust so that the float arm is parallel with the float bowl to carb body parting line . This only works if the floats have not been previously mangled .

The often over looked needle valve seat O-ring. When you can undo the needle valve seat retaining screw and plate and the seat falls out it's pretty obvious that the fuel isn't getting past your needle and seat . It's going around the seat . Replace the O-rings and be happy . Don't cut them on installation , use a bit of grease and they should press in firmly . Verify that this is your dimension and install away.

~kop

Very helpful Kop. So my thinking is as the O-ring on the seat split once a bit of carby cleaner hit it that there as a crack that was letting fuel past the float needle causing the dripping leak I had.

As for the screws at the top I had only just bought some socket head SS ones to replace the ones someone else destroyed. It is amazing what you can do with a dremel and an impact driver indeed.

Offline zap2504

  • Posts: 343
Re: '84 SR250 Garage build. Solo Tracker now, Cafe later.
« Reply #23 on: Apr 29, 2013, 15:02:27 »
Several people have run into problems trying to use pod filters on Yamaha XJs (as well as other CV carbs). The proven fix has been to re-use the carb-to-airbox rubber connectors when installing the pod filters so a cleaner line of air hits all the air correction jets and CV vacuum port. If these are NLA, you can use rubber plumbing connection fittings in appropriate size to fit the outside of the carbs; found in most home centers.

Offline Brodie

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  • Gold Coast, Queensland
Re: '84 SR250 Garage build. Solo Tracker now, Cafe later.
« Reply #24 on: Apr 29, 2013, 23:19:52 »
Several people have run into problems trying to use pod filters on Yamaha XJs (as well as other CV carbs). The proven fix has been to re-use the carb-to-airbox rubber connectors when installing the pod filters so a cleaner line of air hits all the air correction jets and CV vacuum port. If these are NLA, you can use rubber plumbing connection fittings in appropriate size to fit the outside of the carbs; found in most home centers.

I had thought about that but I would rather have a bit of better filtration. I am thinking of grabbing a K&N for it as the only filters at the local bike stores were Uni and were a bit to costly for my liking. But on the other hand I would love to have a velocity stack on it to try and push as much power out of the 250 as possible.
« Last Edit: Apr 29, 2013, 23:39:21 by bvander »

Offline Brodie

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Re: '84 SR250 Garage build. Solo Tracker now, Cafe later.
« Reply #25 on: Apr 29, 2013, 23:38:25 »
I spent the morning running around to all the local bike shops to get the same answer about the O-ring. Yamaha told me I would have to order the whole float seat if I wanted it at a grand price of $45, both the parts manager and I spent a good minute laughing and then he directed me to a bearing shop. The same shop I grabbed my wheel bearings from. When I went in I was able to get two sizes that would fit but neither in viton. After a bit of searching we found a viton ring that would fit and I took the other two as backup.

Once I was home I set head to rebuild the carby and I decided to take a few pictures on the way. I painted the top with some spare red paint I had just so in future people will know the carby has been looked at. After I put everything back in I had a look at the float height as Kop mentioned in his guide "Carburetors from the grave. www.dotheton.com/forum/index.php?topic=24283" and sure enough it was high. Someone had messed with this before me so I reset it and went on putting it back together.

After I had put the carby back on the bike it was still leaking petrol out of the air intake which had me wondering why. I started the bike and let it warm up then gave it a gut full and shut it off. I watched and waited but there was no leak so all is well.

I took her for a run around the block and the performance has improved greatly, I had her up to 70kph in second and she still had a bit to go. Now I just need to find an air filter that isn't going to mess with the CV carb.

Thanks for the help Kop.
« Last Edit: Apr 29, 2013, 23:51:01 by bvander »

Offline Brodie

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Re: '84 SR250 Garage build. Solo Tracker now, Cafe later.
« Reply #26 on: Apr 30, 2013, 02:59:47 »
Turns out I don't have the original intake pipe, just the air box. So I have been looking for a velocity stack to fit. Having next to no luck finding one in my budget I finally found an Aussie site which have a larger selection at a good price. They even have rolled edges which is exactly what I was after. http://www.jntperformance.com.au/index_c269035_2.html

I remember reading somewhere the other week about velocity stack lengths and an equation to work out what was best but can not remember where. I think it might have been linked on Texasstar's CB200 build.

I just went and checked how much room I have for the stack and it looks like 90mm is going to have to be the go unless I move the battery to somewhere else.
« Last Edit: Apr 30, 2013, 03:07:28 by bvander »

Offline eyhonda

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Re: '84 SR250 Garage build. Solo Tracker now, Cafe later.
« Reply #27 on: Apr 30, 2013, 08:25:25 »
Sorry, late response on the cable vs hydraulic question (bottom of page 1):

The general feeling around the sportbike circles is that cable has a better feel than hydraulic.    My cbr900rr had one but it was a bear in traffic.   Smaller bikes won't have that issue though. 
90 RC31 Hawk, parts collection phase.
72 CB175, cafe project.
15 CBR300r, tri-color.  My new daily ride.

Offline Brodie

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  • Gold Coast, Queensland
Re: '84 SR250 Garage build. Solo Tracker now, Cafe later.
« Reply #28 on: Apr 30, 2013, 20:46:38 »
Thanks for the reply. I am thinking I will leave that for a while as it is not needed.

From all the reviews I have read people say it is smoother and feels better but there are a hell of a lot more people out there converting from hydro to cable.
I will give it a try some time in the future and decide for myself. If I don't like it I will stick it on my MiniCafe Z50A.


As for my grand idea of moving the battery it fell short by all of 10mm. I was planning to run longer bolts through where the rec/reg is mounted and make up a metal frame to hold the battery in.
I ordered a 125mm Velocity stack and moved the battery lower which looks a hell of a lot better than it did previously. I also tryed to tuck the leads up but will have to make a longer positive as there is just not enough room.

I will post up some pictures once I have all of it looking alright but for now the battery is mounted where it will stay until my welding skill increases greatly or I build a cafe seat.
The battery is mounted using the trusty old "Multi purpose adjustable mounting straps" AKA zip ties. See how it hold up :S

Offline Brodie

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Re: '84 SR250 Garage build. Solo Tracker now, Cafe later.
« Reply #29 on: Apr 30, 2013, 22:06:18 »
After a bit of soldering and cutting wires I have the battery mounted and the lead tucked away. The clips for the Reg/Rec annoy me and I will have to do something about them in the future but I am unsure if I will keep the Reg/Rec mounted where it is so I have left them for the moment.

Also while I was out taking a few pictures I pulled my XL250 to get a picture and have a run down the road on it. I plan on restoring it and using it as a two up bike for when the missus wants to come for a ride. I did a fair bit of riding on the XL when I was a teenager and it had a hard time since I jumped on it straight off a 1969 Z50A. She will get some loving in the years to come.
« Last Edit: Apr 30, 2013, 22:09:23 by bvander »