GT Kit Jetting

[Rich_T]

I quite agree with Diablo, the temp gauge is showing something that most people do not get to see. I understand Soul Surfers concern and to be fair we have been in contact and are systematically working through the options. Once these are exhausted there is not alternative but to ride through it.

On the subject of cylinder heads again...you can get your 40 or 50% squish band, but this is always at the expense of combustion chamber volume, plug position and plug protrusion. The picture of the machined head J1MS put up has a wide squish band but in creating this you have lost head volume which needs to be recovered (in an off centre head this means a lot of manual work and that costs, it is no production solution with an economic cost). From a production point of view, off centre heads are a pain unless cast in, central heads are way better and easier to manufacture and that is the way I always go with a semi spherical head for highest volume with lowest surface area.

For those of you who have an interest in this I posted all the drawings and files to construct a really solid lathe fixture for cylinder head profiling http://www.granturismo.pwp.blueyonder.co.uk/Tooling.htm everything is there that you need. Additionally, a couple of people have asked me about conversion of RM250 Wiseco and TS250er pistons to take 16mm pins so I've also posted the drawings for this conversion bush too.

Over time, I'll probably add other bits an pieces to this collection. If you use it and like it, let me know and, if you post, tell 'em where you found it.

[Matty]

I quite agree with Diablo, the temp gauge is showing something that most people do not get to see. I understand Soul Surfers concern and to be fair we have been in contact and are systematically working through the options. Once these are exhausted there is not alternative but to ride through it.

On the subject of cylinder heads again...you can get your 40 or 50% squish band, but this is always at the expense of combustion chamber volume, plug position and plug protrusion. The picture of the machined head J1MS put up has a wide squish band but in creating this you have lost head volume which needs to be recovered (in an off centre head this means a lot of manual work and that costs, it is no production solution with an economic cost). From a production point of view, off centre heads are a pain unless cast in, central heads are way better and easier to manufacture and that is the way I always go with a semi spherical head for highest volume with lowest surface area.

For those of you who have an interest in this I posted all the drawings and files to construct a really solid lathe fixture for cylinder head profiling http://www.granturismo.pwp.blueyonder.co.uk/Tooling.htm everything is there that you need. Additionally, a couple of people have asked me about conversion of RM250 Wiseco and TS250er pistons to take 16mm pins so I've also posted the drawings for this conversion bush too.

Over time, I'll probably add other bits an pieces to this collection. If you use it and like it, let me know and, if you post, tell 'em where you found it.

Hi Richard, so in a nutshell if an EGT wasn't used then Soulsurfer wouldn't have been any the wiser? Therefore he could have had 1000's of miles of trouble free riding ? I'm beginning to think the EGT has now become a paranoia meter for Lambretta riders.

[soulsurfer]

Hi Richard, so in a nutshell if an EGT wasn't used then Soulsurfer wouldn't have been any the wiser? Therefore he could have had 1000's of miles of trouble free riding ? I'm beginning to think the EGT has now become a paranoia meter for Lambretta riders.

No 'cos it runs like s**t!!

Yesterday I was out on my TS1 when I noticed temps rising, so I adjusted trottle positions to get home. When I investigated the problem the head was leaking. Had it not been for egt I would be none the wiser and probably facing an expensive repair bill.

There is a problem with the GT as it's not jetting correctly and the egt is confirming this!! So give it a rest Matty or are you one of those people that'll keep on until you get the answer you want regardless of what's being said? (Maltby Media Co.???)

[Matty]

Hi Richard, so in a nutshell if an EGT wasn't used then Soulsurfer wouldn't have been any the wiser? Therefore he could have had 1000's of miles of trouble free riding ? I'm beginning to think the EGT has now become a paranoia meter for Lambretta riders.

No 'cos it runs like s**t!!

Yesterday I was out on my TS1 when I noticed temps rising, so I adjusted trottle positions to get home. When I investigated the problem the head was leaking. Had it not been for egt I would be none the wiser and probably facing an expensive repair bill.

There is a problem with the GT as it's not jetting correctly and the egt is confirming this!! So give it a rest Matty or are you one of those people that'll keep on until you get the answer you want regardless of what's being said? (Maltby Media Co.???)

That's strange, I seem to remember asking Richard the question. As you've replied I'll say that no, I'm not like Maltby Media Co. I just like to know the outcomes of problems like yours so that I don't make the same mistake in the future. I won't give it a rest and who are you to tell me to anyway?

[soulsurfer]

You used my name, I think I have a right to reply.

If you "just like to know the outcomes of problems like yours so that I don't make the same mistake in the future" then what is your point regarding EGT as it's not helping anyone? Actually.... don't bother

Anyway, back to the topic.......

[J1MS]

The scooter has symptoms that we the forum users, use our experiences and knowledge to try and reason why, offering our sugestions
for a possible cause. This is what the forum is for, my comments are only my guestimates as to what my be a factor... This didn't mean my thoughts are correct and there are people on this forum better placed to offer reasonings than myself.. But it would be good to know the outcome. But at the moment we are speculating as to what could be the cause...

The GT Kit is normally a trouble free kit and a kit that when I rode one impressed me... So as I said it would be good to know the outcome!

[Rich_T]

It is not a Paranoia meter, they are usually fixed to small areo engines to identify the same problems. I'm interested because I haven't seen this information before and it is an opportunity to get some interesting information.

The million dollar question is how usefull or predictive the information is going to be. If it just transpires that Lambretta engines just have hot spots at certain revs and nothing can be done about it then the EGT will help identify the trouble spots and you keep away from them. The ideal is to be able to resolve and fully comprehend why an engine exhibits some of these features and publish data accordingly.

Gentlemen, some of your panties are up in a bunch. The purpose here is to learn and move forward, sniping is a total waste of time and effort. Consider this, you might just learn something really critical about the use of these gauges (they are quite new in our arena) which means you might not spend half your day sitting in the rain on the side of an A road waiting for the RAC. Maybe then you'd think, pherhps I should have taken some of that info on board.

[cryogenic]

I totally aggree with Rich_T here and have said this a number of times on this forum about EGT`s even for the great unwashed, If you know nothing about engines this bit of kit which i think is one of the best bits of kit to adorn our machines (like the Foxhat) since heat seizures started gives the first indication of a problem. Like so many of us have done when you here a noise, rattle, flutter we dont always react quickly enough or choose to ride on until the motor goes pop. If it shows the critical melt down temp like Al said it could just be the weak phase in the engine which could be anywhere on your motor. It could also be the rider backing off and going lean whilst still under power which might not manifest itself in a lack of power or speed, then surley this real time info is invaluable. in the training world where i`m from its only a problem if we don`t know about it and when we do we can react accordingly to it. My EGT has saved my motor at least three times on very long distances and i swear by mine. Nuff said :baddevil: