re-bore

[norman]

Hi All,
Finally got my engine back from the garage after 9 months! It`s been re-bored and had new crankshaft oil seals fitted. Any tips on starting it for the first time and running it in???

[norman]

Thanks

[fortypence]

May 21, 2011 22:13:22 GMT 1 butchers said:

here you go fella

rdlccrazy.proboards.com/index.cgi?board=info&action=display&thread=7091

Excellent piece of advice there, thanks

[norman]

Okay, Still having big problems with the bike!!!
Any thoughts are welcome.
I have managed to get the engine running after it`s re-bore but it`s pretty much the same as before.
I`m running it in as advised by not going above 4000 rpm. This equates to 30 mph and there doesn`t feel as if there is anything more on tap.
I have fitted new jets and needles to both carbs, fitted new reed valves, fitted a new air filter and de-coked the exhausts. The cylinder head was de-coked when the engine was apart and the garage fitted new crankshaft oil seals and small end bearings. I have also fitted a new wiring loom, plugs and checked the ignition timing.
There is a little clutch slip when I reach the magic 30 mph, could this mean a clutch overhaul?
Any help and advice welcome.
Cheers,
Norman

[btlc]

Have you checked the adjustment on clutch and what type of oil is in the gearbox.

[norman]

I`ve fixed the clutch slip but I`m still having problems. The bike still won`t go above 30mph.

I had checked the ignition timing with a timing light but I`ve just managed to borrow a dial gauge and check it properly and it`s off.

Using the adjustment slots, I can adjust the timing as per the haynes manual but the closest that I can get the F mark to the timing mark is 11mm (22mm at the other extreme).

Is there any way to get further adjustment?
Or could something have been fitted wrong when it was re-built?

After it`s been out for a run, the plugs are wet but not really oily wet if that makes sense, I`m thinking un-burnt fuel. I have tested the ignition coil and it seems ok and compression is 130 psi.

Again, any help or advise will be gatefully accepted.

[cb250g5]

What sort of a bike is it? If its geared to do 30 MPH at 4,000 revs, that's 75 at 10,000 - seems unlikely to me.

[davey]

start from the ground up mate sounds like if the problem is the same as b4 then i would doubt that its the rebuild ,, not to say it isnt offcourse
I would start with carburation especially jetting and make sue all the specs for the carbs are correct , do you have standard pipes and when you dsay wet plugs what color is the centre electrode on the plug as if its running so rich as to me it sounds then jets and needle heights might need to be checked b4 going to deep ,,, what im trying to say is its a proccess of ilimination . good luck m8 im sure all will come good

[norman]

Hi All,
I should have said the bike is a 1981 RD 250 lc and it`s fitted with standard pipes.

Davey,
thanks, I`ve been trying different things out with the carbs. I bought new jets and needles which included 190 main jets and Y0231 needles and it would tick over but you couldn`t release the clutch (in gear) without it stalling. I tried Y118 and Y184 needles with no effect. I eventually put the 170 main jets and needles that I had taken out back in and it will move off now but 30 mph is max.

butchers
thanks for the link. Before I borrowed the dial gauge I was doing something similar envolving marking a bike spoke down the plug hole at top dead centre and then measuring another mark 2mm higher and setting the F mark and the timing mark that way. I thought that I had it correct and I checked it with the timing lamp and it seemed fine. Probably my readings from the dial gauge that are wrong.

I think I`ll need to tinker with the carbs a bit more.

[norman]

Spark plug electrodes are black and the insulator is a light brown and both are wet.

I looked at the dial gauge again and I`ve been trying to set the timing to 0.2 mm BTDC!! It`s usually human error!! Anyway, the timing is still not near. When I have the F mark lined up with the timing mark, the piston is reading 5.3 mm BTDC and I can only adjust it further away.

[chippy28]

Norman,it would help to know your rough location aswell because you may have someone who could maybe help you out if needed just around the corner.