'73 CB250 - Doing it right this time round.

[Maritime]

Powder should stay put on the brake cover so shouldn't be an issue. XB's comment was the screens restriction negating the advantage of stacks. They will run great with stacks as long as you get air in them and jet correctly for them, you are better off to find a foam filter like a Uni that will fit over the stacks and filter yet still allow air to flow into the stacks. Better still would be to put them in a box with a filtered opening. That reduces the effects of side wides and surges.

 

[xb33bsa]

More about if the brake would just stop working really. But I will be looking at the engine performance once I get it back on the road.

Would the filters be better placed at the bottom of the stack, close to the carb?

I only really went with stacks because I didn't want cheap pods, and the mounts for the stock airbox had already been remved when I bought it, so I just removed the other side too.

Can the CB250/350 run well with velocity stacks?

those stacks you got there don't have filters....some stack mfgs. do put the screen next to the carb mouth but that is even worse for airflow :'( a huge fail, they should be shot for even selling them
what you need is some good sized filters on those stacks,without the screens that are now blocking airflow at the mouth of yer stacks
some 3-4" diameter x 6" long uni foam filters would probably work great,plus it helps fill up the empty area under the seat,then fab up some slick side cover panels and you really got something !!

 

[Green199]

ahh ok, thanks for the information guys.

I'll look at getting some foam over the end of them!

 

[Green199]

What's the maximum amount of 'wobble' the rim can have in it?

Trying to true the front rim, and I have about 1/8" difference in the vertical direction.

Ive got about the same in the horizontal direction for the rear.

Having a bit of difficulty getting it lower than this.

 

[xb33bsa]

1/8" is more that you want, i would not want more that 1/16" and that would be only if it was impossible to correct(a bent/tweaked rim for example)
are you using a pair of dial indicators ? these really do help as you can watch the rim move when changing tension of nips
was the rim bent ? what did it run like before you unlaced it ?the last rim i dun was within .010" but it was a new rim(but an imperfect akront)
the best course of action may be to focus now on any nips that are over or very tight
go round and round and loosen each one of the tight ones only less than a turn at a time until you relax the entire wheel assembly a bit,then start over

 

[Green199]

1/8" is more that you want, i would not want more that 1/16" and that would be only if it was impossible to correct(a bent/tweaked rim for example)
are you using a pair of dial indicators ? these really do help as you can watch the rim move when changing tension of nips
was the rim bent ? what did it run like before you unlaced it ?the last rim i dun was within .010" but it was a new rim(but an imperfect akront)
the best course of action may be to focus now on any nips that are over or very tight
go round and round and loosen each one of the tight ones only less than a turn at a time until you relax the entire wheel assembly a bit,then start over

Not using indicators, just using a pen as a marker. The rim was alright before I unlaced it, I had a friend true it previously.
There are a few loose and a few too tight. Ill have a crack at the method you just said and try again!

Ill just keep trying til I can get it straigtened out.

 

[Green199]

I kind of started again, and found a good video online which broke the method down into easy steps.

https://www.youtube.com/watch?v=FCQtuGfz3c8

I've got the 'wobble' and 'hop' down to about 1mm so i'm going with that. If necessary I guess I can adjust it a bit when the tyres are on.

 

[SASO Racing]

I cant ever get them perfectly straight, 1mm is more than ok.

 

[Green199]

I cant ever get them perfectly straight, 1mm is more than ok.

I found it easier to get the side to side wobble in spec. The up and down 'hop' seemed much more difficult to achieve.

 

[xb33bsa]

I found it easier to get the side to side wobble in spec. The up and down 'hop' seemed much more difficult to achieve.

ya dun reel good
don't ferget t balance once you get the tars mounted

 

[Green199]

ya dun reel good
don't ferget t balance once you get the tars mounted

Tyres all fitted and wheels balanced!

Took them to a local bike shop to fit for me, didn't trust myself to not scratch the rims! haha

 

[Green199]

Got a few pics of the wheels. All the bolts are in the process of being replaced by stainless hardware.

Got a quick question about the motor as well. My engine frequently gets stuck in gear and is a right pain in the ass to get back in to neutral.

What could be causing this? The only idea I have is that I potentially left the clip for the output shaft off during the rebuild, as it does seem to have a lot of lateral play in it....

 

[xb33bsa]

if you are trying to find nuetral while the engine is running and the clutch pulled in then it is possible the clutch is dragging slightly,this is the only time a clutch will effect shifting
with the engine dead and the bike on the center stand you should be able to very easily get all gears and nuetral (don't need to use the clutch to actually shift)as long as you are rotating the rear wheel gently so the countershaft is turning, you will need clutch pulled in so that it dont try to turn over the engine
when riding the bike the clutch has nothing to do with shifting gears up or down it has zero effect on any of the shifting mechanism all the clutch does is eliminate power coming from the crank
so no. 1
make sure the linkage if you have any rearset linkage is all set and not binding
no.2 try loosening the deten ball on top the cases a 1/2 to a full turn if this helps you want to pull the unit out and check it for a russty spring
last resort is check the linkage inside behind the clutch,you will need to take things apart,a new clutch/primary cover gasket and the special crankshaft nut socket will be needed to do this

 

[Green199]

At the minute I don't have a clutch cable so all attempts at shifting have been without the clutch anyway.

Just trying to shift while rolling the bike back and forth with the engine off, and with rearsets. They aren't binding so Im sure I can rule them out.

The detent ball....is that this bolt?

 

[xb33bsa]

yes that is the drum detent you will need a maggot on a stick to lift the ball out
it is not real common to have an issue but is easy to check
is the shifter motion stiff and notchy ?

 

[Green199]

Ok, Ill have a check in a bit and see if its the problem, if not the clutch cover will be coming off for an inspection.

The shifter motion seemed ok, but I couldn't really try it a lot because it kept getting stuck.

 

[xb33bsa]

i had a sticky shifting issue and it was screw #34 loosened up causing part #7 to catch and bind
but you must pull the clutch basket and that requires the special socket tool
http://www.cmsnl.com/honda-cb250k0-general-export_model15728/partslist/E15.html#results

 

[Green199]

Ive just whacked the right side cover off, and removed the clutch basket and oil pump etc.

Looking at the shifter mechanism below, it all looks like it was installed correctly but obviously something isn't working right.

Is there meant to be a circlip on the selector shaft? I can remove the selector arm and shaft from the right side of the motor....

 

[xb33bsa]

the clutch cover case has a cast in thin section that sticks out to keep the shift shaft pushed in place so it has very limited axial movement

 

[Green199]

Right ok, thanks for the reply.

At the minute, im turning the front sprocket and the shift mechanism, but im not managing to get into any gears now.