Poor Running

[Doss1961]

Hello
I'm restoring a 250R and have finally got it running after a complete engine rebuild but the left cylinder seems to ticking over OK and the exhaust is very oily at the end but the right cylinder is making a put put sound and the end of the exhaust is very dry.

If I put my hand over the end of the right hand exhaust when it is running there does not seem a lot of pressure a friend of mine wondered if I had put the crank oil seal in the wrong way round (I'm talking about the one that sits in the casing) I've also swapped the plugs around to see if it was a faulty plug but it made no difference.

I'm at a bit of a loss what it could be.

Would any members have any ideas what I could maybe try.

Thanks in Advance
Paul

[Vintageman]

Which way did you put the seal? My guess it should still seal (at least for a while) but may restrict oil flow to that bearing? I assume you are talking the out seal.

Does that cylinder spark nicely?

Is plug showing wet like it is getting fuel?

A better quick way to see if it is seals is to put you hand over the carb s and see how well the suck air in and you can compare as well since one runs OK. If you take both plugs out you get a good feel at carb bell mouths, just by kicking over. To me seal has to leak bad not to run at least somewhat steady.

[Doss1961]

Hello
I have put a 21 sec video of the bike running under the title Suzuki T250r 1971 on U Tube I'm not much of a techno head so I'm not sure how to put a link from this message (where's my teenage so when I need him)

Thanks
Paul

[Doss1961]

Hello
Yes I'm referring to the outer seals I had the crank rebuilt with new bearings and inner seals by a specialist company called Grampian motors.

Paul

[Zunspec4]

Hi Paul,

Grampian Motors have a sound reputation so it's unlikely that they installed a seal backwards. Stranger things have happened though. Just a thought, but have you synchronised the carbs. Watching your video the left is running strongly and the right intermittently. Try raising the tick-over screw on the right side to up the air flow on that side. Also make sure the pilot air screws are set equally as they control the fuel flow at low revs.

Cheers Geoff

[GTandcbr]

+1 on Grampian motors they are normally very reliable. Here is your video link https://youtu.be/oCBUo6AXY_g" onclick="window.open(this.href);return false;

[Doss1961]

Hello
Thanks for the advice and putting the video clip on the message board I will try the mixture screw and idling screw today, is it one and a half turns out for the carbs that what is for my RD?
Thanks
Paul

[GTandcbr]

Yep 1 1/2 turns out. Look here
http://www.3cyl.com/specs/suzi2tuneup.jpg" onclick="window.open(this.href);return false;
But remember that is the stock setting each bike and the way its ridden can be different so it's a starting point

[Doss1961]

Hello
I swapped the wires for the coils around and the plug leads to see if it was a faulty coil but it made no difference and when it was running at about 2000rpm I lifted the throttle cable on the left carb to see if it was a fueling problem but it made no difference the r/h exhaust is getting hot whilst the L/H one is cold.

So at the moment I'm abit lost what to try next.
Paul.

[tz375]

Do you have a spark on the right side? If not check wiring, points, etc.

[GTandcbr]

If your left hand exhaust downpipe is cold when the engine is running that cylinder is not firing properly if at all. So you need to check it sparks at the right time and that fuel is getting through.

[Doss1961]

Hello
I am getting a spark on both plugs.

[GTandcbr]

So you need to check the timing so you know the spark is arriving at the right time. You also need to check fuel is getting through.

[dollydog]

take the left plug out and see if it's wet. if you have a spark there it should at least run, even if your timing is a bit out. but with no fuel getting through, the plug will be dry as a bone you could of course have filled the left crankcase with mixture, which is why it's not firing. if you're lucky, you'll have an engine with drain plugs for below the crank - they'll be either 14mm or 17mm across the flats. otherwise it's turn the petrol off, open the throttle wide [plug still out] and kick like buggery til it's empty, then start again
cheers, dd.
ps, my t250 engines have got the drain plugs. look at spark plug first, then take the left CRANK drain plug out - and don't have a lit fag in your mouth while you're doing it don't forget to replace it - TIGHT.

[Alan H]

Make sure that both carbs are open the same amount at tickover. If one is open less, it'll get less fuel and not fire as well as the other side.