G Digger

February 27

Thanks for that.

I think the best thing for me to do is post this on ebay specifying its to fit a dt250 1M1 spec.

Cheers Digger

February 27

Hi everyone I have a barrel, piston and head off a 1M1.

I know its off a dt250 but was wondering what the difference was between the 1M1 and the 1R7 engine.

It is a spare so I am going to put on ebay once i am sure what bike its off.

When researched it says its off a dt250f 1979.

The 1R7 it says is off a dt250 1977-1980, hence the confusion.

Thanks in advance for any helpful info.

Digger

9 minutes ago, G Digger said:

Hi everyone I have a barrel, piston and head off a 1M1.

I know its off a dt250 but was wondering what the difference was between the 1M1 and the 1R7 engine.

It is a spare so I am going to put on ebay once i am sure what bike its off.

When researched it says its off a dt250f 1979.

The 1R7 it says is off a dt250 1977-1980, hence the confusion.

Thanks in advance for any helpful info.

Digger

Hi a quick update, apparently the 1R7 is european/UK spec and 1M1 is US spec.

Next question are they inter changeable?

T.I.A Digger

May 14, 2023

Hi everyone

I have just reinstalled a oil pump on my dt after years of premix. It appears to be smoking a lot more. Do I remove a shim or add one to lesson the oil/fuel mix. I’m thinking add so it lessens the stroke of the pump. Am I right or wrong.
T.I.A Digger

February 20, 2023

Hi

sorry for late responce.

bike back together all gears shifting nicely, neutral abit hard to find but manageable. read somewhere if chain a bit tight can cause this issue so i will loosen chain to see if improves.

Thanks for everybody's help so far, cheers Graham

February 4, 2023

Hi

I looked into the welded part and apparently the later models came with this part welded. Must have been a mod due to problems before.
the teeth aren’t tight so that’s 2 things off the tick list although I am changing the shaft for the one I’ve bought as this one is slightly bent (about.5mm)

Thanks for all your help will let you know how it is when it’s running

February 3, 2023

Hi Snakebite

I've had a look. You are quite observant there is a nick in the change shaft but I think it’s how it’s made for clearance to stop it fouling on the drum. Have cleaned the drum now. Have put it together again tonight and it went through all the gears ok (WHAT !!!). Didn’t do anything different. Had to disassemble it to fit new shaft when it arrives so hopefully it will work .

February 3, 2023

Hi

The top picture where you can see the worn bits on the spider, I'm not sure if that's just some bits of the file I used.

I think the selector actually connects with the dowels behind that plate. see 2nd picture.

The spider like thing I think that is just a way of securing the dowels in situe, i.e bent over them to secure in place.

As for the nick on the lever I will have a look at that, I have just bought a second hand replacement for that.

Anyway thanks for your help. Will let you know what I find

February 3, 2023

Hi Neo

l have had a look, interesting but would help more with pictures.

mine has not got clutch built up and not filled with oil yet.

just making sure gears engage before rest of build.

February 2, 2023

February 2, 2023

Hi Neo

have tried on every tooth tonight and it doesn’t move the drum. I think the movement when using the file is because it is radial so it’s moving it using 2 pins (top and bottom)but when using the selector it’s a push or pull movement on one of the pins.

I think the selector drum has to be addressed so the change is lighter and smoother so I think it’s cases split and further internal investigation.

will keep you informed.

cheers mate and thanks again

February 1, 2023

Hi thanks Neo.

I’ve had a look. It appears to link one tooth different to how I have it. I think I have tried it all ways but I will have a go in the morning.

I have changed the internal selector drum, selector forks plus shafts.

they looked ok but I thought there must be a reason why the shaft was bent!

they are used but I thought I’d try them.

internally I think it’s all good because when I use the file to rotate the selector it works through all the gears.

Thanks again Graham

will let you know tomorrow

Yes got a Haynes manual but very vague description. Does look similar to how I’ve done it. Also I downloaded a manual off emanual but again a bit vague

February 1, 2023

Hi

I’m having problems with my gearbox after strip down.

I believe the problem was already there before as it was a non runner and when stripping I noticed the gear change shaft was bent about 2mm.

I have straightened it now to about .5mm.

When I try to change gear when gear selector is built up I get nothing but if I use a flattened file as a selector it changes ok.

see photos

Any advice would be great cheers Graham

February 18, 2022

February 18, 2022

Hi Neo

all sorted now had to adjust spring length but all working good now. Cheers Graham

February 17, 2022

Lesson learnt, this is my second refurb

And I think I got a bit cocky as my first was a Honda and honda seem to have twice as many parts to them as other bikes.

hopefully will sort it in morning. Will let you know cheers

February 17, 2022

Nice one, you’ve got keen eyesight,

I will have another try in morning.

at least I now know I’ve got the right linkage.

when I dismantled this bike I was too cocky thinking it would be easy to suss everything out but I was wrong.

cheers Graham

As for the spring I’ve got a collection of them but will look for the original in my drawer

February 17, 2022

Is that not the spring?

February 17, 2022

Thanks Neo

I think I will get a new one but still don’t know how the linkage works. Might have to improvise a little to attach spring to brake pedal. I have posted on Facebook forum for someone to post any more photos, hopefully someone will send photos without too much abuse
thanks again for your help cheers Graham

February 17, 2022

Hi NEO
Thanks for your reply, yeah mine is different. The brake switch is the back side of frame and the pedal has no hole for spring to attach.

I have attached some photos but no matter which way I position the linkage it doesn’t work. It actually pushes the spring in when you push the brake on.

where I have put the red arrow. I wonder if that bracket will help in some way?

further investigation is needed.

thanks again NEO

February 16, 2022

Hi everyone

I am trying to connect the rear brake light switch and the linkage from the brake light switch to the rear brake pedal has got me scratching my head a little.

it is the linkage from the spring that returns the brake light switch plunger to normal after the rear brake has been released,

there is a fixing that fits on the rear of the pedal with a connecting rod on it to connect the spring, no matter which way i position it the movement is the wrong way.

it has been a year or more since i dismantled it and i am not sure this is even the right bit as I cant find the linkage on cmsnl.

a photo of someones linkage would be appreciated.

or a photo of where the springs attaches to.

I hope this makes sense

cheers Graham

January 10, 2021

January 10, 2021

Hi Neo

would both sides need to be removed?

January 10, 2021

I’m pretty sure that’s my problem. It makes sense now, I assumed the oil found its way through oil passageways. Will drain and check it out tomorrow. Thanks again for your help as the photos.

i remember when I joined this club, you were helpful then. Cheers Graham

January 10, 2021

1 hour ago, NE0 said:

Hi Graham

There may be nothing wrong. the Simplest reason might be that although you have it on the engine stand , it may not be replicating the angle when on the bike. If its front end is elevated then the dipstick will be in the oil prematurely as its pools in the corner so to speak.

Having said that, there are a couple of things to consider, bear in mind the engine is merely two boxes, in one box is the gears in the other box is the clutch. The same oil sits in both boxes. The oil will fill both sides via the open bearings.

How much oil did you drain out? Is the dipstick the right one length wise? When you replaced the bearings, were they identical replacements,? i.e open type not sealed bearings. Did you remove the side casing of any new bearing to make them open? (just thinking what might stop the oil getting from one side to the other). Was it all cleaned thoroughly? (sludge oil stopping the new oil from crossing over). Did you soak the new clutch in oil? I appreciate new cork plates won't absorb the missing half litre, but has the level now dropped as the clutch soaks up.

I'm not for one minute suggesting you haven't done any of the above, but you said any ideas on what might be wrong.

Hope this is of some help. Keep us informed.

Thanks for that Neo.

i think you’ve hit the nail on the head with the closed bearings. It’s my first engine rebuild and obviously didn’t think it through,

I will check the bearings and open them up if necessary.

Thank you for your tactful answer and not insulting my lack of knowledge.

will let you know

January 10, 2021

No it’s still on engine stand waiting for top end to be finished. Added oil early to see if any leaks so if I needed to strip it would be easier. I have levelled engine to replicate it in the frame and put in gear and rotated crank .so far not made any difference.

4 hours ago, finnerz89 said:

Have you tried turning it over a few times and re-checked the

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Posts posted by G Digger