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hi, currently running a jap conversion 110 rod in my ts 225 & just wanted to know if I've got the correct base packer fitted, set up is - bgm clubman exhaust,30mm dellorto carb, 4th gear ratio is 4.99 & 2.5mm packer,pulls fairly well with this set up but seems to hit a bit of a "wall" in 4th, would there be any benefit to say, the top end performance if I reduced/increased the thickness of the packer ? not really clued up on port timings etc hence my question, thanks for any info

Cant really answer this question in isolation

There are a huge number of factors to consider... Why do you think its the packer...?

Where is the piston relative to the bottom lip of the exhaust port at BDC, what squish do you have at the top end?

hi, not sure what the squish setting is I'm afraid , it states on MB's site "for mid to high power " use a 3mm packer & 0.5 mm head gasket, as I said I'm not very clued up on all of this. thanks

Any engine that has modifications for any reason requiring changes to the basic geometry should have the resultant squish measured as a matter of course.

It is a fundamental check to ensure that the optimum is achieved to enable the maximum heat transfer from the piston to the head whilst remaining certain that they do not clash.

If you built the engine yourself, you really should have measured the squish to be sure it didn't blow up on first start.

Sticky's excellent book gives details & is a damn good read, but a little research about two strokes will reveal a lot. Personally, I have found that Two Stroke Performance Tuning by A Graham Bell has been of benefit over the years & is not too complex to follow....

thanks for the info guys, plenty to think about ! also it seems that one of the baffle plates seems to have come loose inside the box, apart from the obvious noise increase would this affect the performance in any way? thanks again

I doubt that any loose baffle plate would help, but IMHO that exhaust would be restrictive to your set up in any case.

If the exhaust has some 'warranty' (Ha!) then it should be replaced, but, failing that, if it were mine, I'd replace the whole tailpipe for one about an inch bore to give the engine a chance to rev & not work so hard against pumping losses. You may lose a little torque @ the bottom end, but doubt it would even be noticeable TBH. The engine will run cooler too.....

Over the last winter I built a TS1 from scratch on a 'new' Indian case... this was my first ever engine build but I had and excellent teacher to help me do this and learnt that their are many factors you need to consider when considering packers, squish etc.

I used a 60/110 crank and ended up with a base packer 2mm and head packer of 2.5mm. The 2mm base packer was determined by checking the port timings, the head packer by the squish (1.4mm). But then you need to check compression, there is a good piece by Darryl Taylor on how to do this (in Scootring I think) which involves a large syringe and a lot of patience! I recommend you do this as the 9.5:1 head I had produced a compression 11.0:1 once I'd done the check. I had to use a re-profiled head to get the compression down to 9.2:1. Ultimately the engine is set up with for mid-range power with 4.7 gearing.

al pushpak wrote:thanks for the info guys, plenty to think about ! also it seems that one of the baffle plates seems to have come loose inside the box, apart from the obvious noise increase would this affect the performance in any way? thanks again

I'd get that repaired or replaced. I had a loose baffle in my bgm clubman and it would suddenly cut out as if the ignition had failed. I changed almost everything in my vain attempts to find the problem. Turned out to be a loose baffle.