LCGB Forums

Evenin' all. I'm finally (!) getting on to the Poland popped drive side oil seal, self imposed deadline, RT 225 rebuild. So here's some questions, any thoughts would be gratefully received...

(1) - I've replaced the blown drive side oil seal with a Casa double lipped Viton item. The oil seal was a git to fit & stood proud of the bearing retaining plate face. Fully pulling the crank in resulted in a locked crank, something I've NEVER! seen in decades of engine building, the only new bits in the mix being the oil seal & gasket.... So I rotated the retaining plate/oil seal in a vice which pulled the oil seal in a bit further, it is still proud of the retaining plate face. At this point I walked away without refitting the crank, so this may be a tad premature, as things may be actually be sussed, but has any one out there experienced anything similar...?

(2) - I'm swapping out the GP kickstart ramped endplate for a sidecasing ramped LI etc ramped unit & need to transfer the layshaft bearing race. I've forgotten how to do this, is it just a case of whacking it out with a suitably sized socket & ditto for the refit?

(3) - Something I've NEVER considered doing... In case time runs out on me, but why not? Is it really a NO! NO! NO! on reusing good nick ali/metal head & base gaskets that were well within squish tolerance...?

(4) - Now the real 'how long is a bit of string?' question...

I've got a close5 AF gearbox that I'm so up for fitting while the engine is as naked as it ever could be. The destructions related talk of 'relieving', 'filing', 'angle grinding' etc have got me traumatised before I've even started... I won't let this stop me, but if anyone out there has any hints/ideas/prayers or 'hacks' (I SO dislike the modern world!) that might help?

With many thanks!

I only use the double lipped viton seal on the mag inner side, single lip rolf seal for the rest.
Remove circlip on endplate and as you said whack it out with suitable drift and if fine reuse.
If thin gasket then I’d replace but anything over 1.5 then I’d reuse.
Good luck on af 5 speed,some fit nice, others are a right ball ache with so many variables involved

Ta Shane. (1) sorted, the vice job worked now for the rest....

4/ no problems in filing a chamfer on the wishbone to get more clearance in 5th gear selection, also in the casing where the wishbone could touch, dont have to remove alot if chamfering the wishbone really.
peeps have being doin this since the cyclone installs

hullygully wrote:4/ no problems in filing a chamfer on the wishbone to get more clearance in 5th gear selection, also in the casing where the wishbone could touch, dont have to remove alot if chamfering the wishbone really.
peeps have being doin this since the cyclone installs

Nice !! I've been reading & rereading the included destructions & probably been confusing myself unnecessarily...

(2) Sorted! The angle grinder option...

(3) Metal base packing/gaskets are re-useable time & again. They are so useful as the template for port matching as well.

Conventional face sealing metal head gaskets should never be used in the first place. They always fail, even if that appears to be 'only' a tiny weep. There is always a way to get around their use, usually by increasing base packing/gasket thickness to obtain the optimum squish, which in turn offers the best piston cooling subject to CR.

Warkton Tornado No.1 wrote:(3) Metal base packing/gaskets are re-useable time & again. They are so useful as the template for port matching as well.

Conventional face sealing metal head gaskets should never be used in the first place. They always fail, even if that appears to be 'only' a tiny weep. There is always a way to get around their use, usually by increasing base packing/gasket thickness to obtain the optimum squish, which in turn offers the best piston cooling subject to CR.

Many thanks, thought that might be the case... A question however WT1, I understand that increasing the base plate gasket size messes with the port timings (summat I'm still trying to fully get my head round, any suggestions for an accessible/understandable 2-stroke tuning guide that explains this? - or might it be that Sticky's forthcoming book covers this...?) so the the question is why does the RT kit have a selection of dedicated head gaskets on the market? Apologies if I'm being stupid...

I am however on plan-B, rebuilding the DJ 185 engine as the the RT host 200 block, even though the end plate fixing/mounting points were repaired a while back are not up to what I would consider usable, & as I'm quite gung ho in what I'll give a go that's saying summat... Thankfully there's nothing going on locally on Sat, so I can take my time...

probs has the range of head gaskets to cater for Italian/Spanish/Indian casings, dif stroke cranks, diff height pistons........

As far as fitting the Clo5e gearbox is concerned, have a look at YouTube. There is often useful stuff on there. Having said that, Ben's instruction leaflet is very thorough.

Interestingly, Ben gave feedback to Uni about their new 200 cases an there are now dimples in the back of the casing to allow for the ends of the wishbone.

Double post deleted

Andy B.L.C. wrote:
Many thanks, thought that might be the case... A question however WT1, I understand that increasing the base plate gasket size messes with the port timings (summat I'm still trying to fully get my head round, any suggestions for an accessible/understandable 2-stroke tuning guide that explains this? - or might it be that Sticky's forthcoming book covers this...?) so the the question is why does the RT kit have a selection of dedicated head gaskets on the market? Apologies if I'm being stupid...

The book that I refer to has always been:

Two Stroke Performance Tunin by A Graham Bell

Although it is old, IMO it is understandable & still very valid.

As far as base gaskets/packing, thicker material will obviously advance transfer & exhaust duration, but the good trade off is a decrease in inlet timing. Often, 'tuned' piston ported barrels such as the Rapido will benefit from that IMO. Even better is the incorporation of a longer stroke crankshaft, & these days with the greater availability of 60+ mm strokes, there appears little reason to go with the standard 58 mm. In fact, I cannot remember when I last bought a 58 mm stroke crankshaft or webs. There were 61 mm crankshafts available some time ago & I liked them.

The whole geometry of an engine is something that should be considered from the outset. As far as head/piston/barrel interface is concerned, to achieve good squish, head volume & good sealing is worth all the head scratching IMO. Fortunately, I now have a small lathe for which I made a head fixture & form tools to suit piston profiles. Therefore, in recent times, a spigot sealing method for head to barrel can be incorporated, although it is a struggle to spigot reed valve cylinders as they have a greater 'swing'

A spigotted head to barrel will not only seal well, but could accommodate spigot profile packing if necessary, as well as offering built in centring of the whole assembly.

There are many, many factors that affect how our engines will run, but I have my fundamental principles. They include ensuring adequate exhaust tailpipe size, increasing crankcase volume, optimising squish & incorporating increased stroke & conrod length. I have found that if those principle are applied, then static ignition timing need not be so drastically retarded, which makes for a more responsive engine. Full retard suits WOT best, but that's impossible to maintain through the whole of a journey.

For the record, one of the best ignitions I have used on the track, is a Motoplat that rapidly advanced from zero then retarded. The drive out of tight hairpins was awesome. A reasonably priced programmable ignition system with power generation that is 'bullet-proof' reliable is long overdue IMO. Unless I have somehow missed the fact that such is available....

Thank you!

Andy B.L.C. wrote: ......so the the question is why does the RT kit have a selection of dedicated head gaskets on the market?

The RT head sits inside the barrel, it's 5mm deep, so the head gaskets don't have the side pressure applied to them as they do on a conventional head & barrel set up.

RT 225 squish question Cologne homeboy Phillip said a 0.3 base gasket would sort it, but added no gasket wouldn't be an issue with a standard stroke crank as proved by recent 'tourist' @ mine Shane, 1.2 will do me (thanks Shane!)

Anytime dear fellow