Heat Seize Issue...

[Hughieboy]

First job. Remeasure TDC (Top dead centre) and remark with a good visible cut into the mag housing. Now set the timing as already recommended (strongly ).
I'm afraid you are going to have to rev it to 6000rpm and beyond to check the timing at that engine speed. No good assuming that it's working; you need absolute clarity and peace of mind.
Do the timing first.

I will Chris.... I used a TDC tool with a sliding measure before and just marked the mag housing when the piston felt like it was at the top of it's travel. From what I've read since I think it would be more accurate to do it by the positive stop method, am I right?

[CHRIS in MARGATE]

I use a positive stop and take the piston backwards and forwards but to be sure I adjust the stop and redo. TDC midway between points. Surprising how far out the timing can be just a couple of mms off the correct mark.
I use an Agusto and I like to watch the strobe rotate to my safe point as I rev it. I have watched mine round to nearly 9K rpm to be confident but was really interested in the cruising speed of between 5000 and 6000 rpm.

[Hughieboy]

Another quick update.... I just rechecked the timing and I'd got tdc out, slightly retarded (a bit like me!)

Currently the static timing is roughly 26 and its retarding down to about 19 under high revs so it's out.... I haven't had the time to take the flywheel off today but will get on to it and let you know how I get on.

Cheers

[Hughieboy]

Righto......

Just wanted to say thanks to all who helped with this and let you know where I'm at....

I have now got the timing set (I think!) correctly, about 19 degrees at fast tick over and it retards down to 15 or 16 under high revs.... The carb was definitely under jetted (the main was 100!)', I have started at 120 which ran ok but was oily, went down to 118 (still a bit oily) and had a good 30 mile blast, it ran well but due to not achieving the 'biscuit brown' colour on the plug I have now switched to a 115. Had a quick 5 mile ride, steady at first and then gave it some for the last couple of miles and it is now a good colour. The other jets etc which came with the carb are 53 pilot, 45 slide and x4 needle. I think this is probably as good as I'll get it myself but want to get it on a Dyno, only thing is I don't think there's anyone around here who has one so I may have to travel....

Starts, runs and goes really well but I'm not sure if I should have stuck with the 118 main? Didn't get the colour I was looking for on the plug but it ran well and wonder if it's better to keep it a bit rich?

All good I think unless anyone thinks I should change anything?

Cheers!

[Hughieboy]

Oh, and the Koso temperature gauge I have fitted was registering 102 degrees centigrade, is this too hot....?

[bike grim]

In my opinion if it ran ok on the 118 I'd put it back in. Always better to run a bit on the rich side.

On the temperature, I have only used a CHT this year for the first time and use it to monitor changes rather than trying to achieve a given temp. Use the scooter and get to know what is normal, then you can recognise abnormal changes. For what it's worth my Ali kit runs normally at between 85-90 Celcius and if I clog it it goes up to about 105. This is sensor under Ht cap rather under plug.

[Raveydavey]

Update....

Thanks again for all your input fellas....

I have a spare main jet kit, I was told that the 'ball park' settings I was supplied the carb with would suit a Mugello 186 or similar, or so I thought. However, the main jet was only a 100 which I assume is too small.

I've changed it to a 120 as suggested however I don't have other spare jets, pilot etc but can get some. Just done a 7 or 8 mile circuit and no binding up (hurrah!) although it's not revving out particularly and I think further adjustment is needed. I have a 122 I could try? I don't really understand the correlation between the main and needle/slide/pilot though..... Currently it now has;

70 pilot
120 main
45 slide
X4 needle second clip position

I will whip the footboard off agin and recheck the timing. So if it's retarding at present to 19 at about half throttle is it recommended to retard it a bit more? Didn't try doing it while wringing the knackers off it because of the neighbours!

That the cam lam carb kit set up. Had the same myself. The x4 slide and 100 main made me realise it wasn't ball park at all. X4 will be why you g t the lean flat spot plus super lean main when you open it up. X13 or x7. 120 main would be ballpark

[Hughieboy]

Update....

Thanks again for all your input fellas....

I have a spare main jet kit, I was told that the 'ball park' settings I was supplied the carb with would suit a Mugello 186 or similar, or so I thought. However, the main jet was only a 100 which I assume is too small.

I've changed it to a 120 as suggested however I don't have other spare jets, pilot etc but can get some. Just done a 7 or 8 mile circuit and no binding up (hurrah!) although it's not revving out particularly and I think further adjustment is needed. I have a 122 I could try? I don't really understand the correlation between the main and needle/slide/pilot though..... Currently it now has;

70 pilot
120 main
45 slide
X4 needle second clip position

I will whip the footboard off agin and recheck the timing. So if it's retarding at present to 19 at about half throttle is it recommended to retard it a bit more? Didn't try doing it while wringing the knackers off it because of the neighbours!

That the cam lam carb kit set up. Had the same myself. The x4 slide and 100 main made me realise it wasn't ball park at all. X4 will be why you g t the lean flat spot plus super lean main when you open it up. X13 or x7. 120 main would be ballpark

Do you mean I should change the needle and revert back to a 120 main? X7 or X13, which would be best? I have to admit, although the plug colour is better with the 115 it did seem to run better with a larger jet albeit the plug was wet....