Messages

1

Tech Talk / Re: PVL Timing

« on: April 18, 2025, 08:08:30 pm »

Sounds like your test method was fine

The options are

Poor installation method.
Old stock shrunk seal
Worn case/shaft

The more i read of the history the more i would be looking at the case. Spun bearings can do that.

2

Tech Talk / Re: PVL Timing

« on: April 17, 2025, 02:36:19 pm »

What pressure did you use to test? I ask as over pressuring can damage a new seal. You can get lucky and reposition the seal lips if not ton on assembly. I recall your previous issue with the seal not fitting thus not sealing.

3

Tech Talk / Re: Wiseco Ring End Gap

« on: April 10, 2025, 05:31:46 pm »

 Wasp is correct  and the gap should be fine.  My calcs are not too far off your actuals and bearing in mind a higher compression means more heat thus more expansion.
 

4

General Discussion / Re: New Members

« on: March 19, 2025, 09:47:11 pm »

What i and many guys i know still use the knowledge base that is the core of the website, OZVMX was one of the premier places for spot on knowledge world wide  and still is according to google. As for the day to day humdrum stuff Buy Swap Sell wanted Bookface handles that as it has a wider audience even if its not only on the OZVMX bookface page. Specialist groups cater for the odd and sometimes a few pearls of wisdom from people who helped make the history chime in. You can almost hear the youngsters chins drop.

Im glad this website is still up as my memory isnt as good as it use to be but just like looking for a tool or a part in my
shed, I know where I seen it last. Likely the reason new to the game prefer just to ask on facebook and decide for themselves who is full of crap or ask an AI robot than do a bit of research on reputable websites. Takes a while to learn where not to ask for advice and thats Bookface or Scambook whatever you call it.

Many of my mates I met via this place are on Bookface and we chat from time to time  though only a few contribute to the bike pages. When Bookface gets taken over by AI or the scammers or has a meltdown, the a few who know about this Website will come back and just maybe all the contained experience will be again used. Unless MA find away to tax that too.

5

Tech Talk / Re: PVL Timing

« on: March 13, 2025, 09:27:46 pm »

Spare nozzles are pretty handy. Cut the nozzle on a 45 degree angle or whats comfortable for you to hold while working on the engine. Then on the tall side nip a small Vee out of it so its about 2mm wide. Thats how wide your sealant will be, the height will squish down giving you a full cover of the case surface. Wider surface needs a wider Vee. Squeeze too hard you get more sealant travel too fast and you get less. Do a few practice lines so you get the feel and squish it so you can see how wide the bead ends up.

6

KTM / Re: Dark clouds hanging over Mattighofen

« on: March 09, 2025, 07:27:40 pm »

 A KTM as a military vehicle? naa.

History has shown a more utiltarian choice rather than a high strung bike, I can think of WLA harley Indians. Enfields  and BSA, Australia liked the BSA B40 Suzuki GS400 and the Kawasaki W1. All the models i can think of have been solid medium range road bikes with the KLR650 being the most sporting although even that was given an agricultural Diesel engine  for some markets.

 Offroad ability has never been a consideration rather ease and length of maintenance periods, reliability and i guess pricing. With advanced signaling and communications i doubt bikes would feature much in any conflict as they were mostly used as dispatch or for Military police. Orange isnt the best shade for camouflage so thats an additional cost im sure neither party would be willing to cover when so may other choices  are out there.

7

KTM / Re: Dark clouds hanging over Mattighofen

« on: March 01, 2025, 11:09:46 pm »

So KTM have filed for bankruptcy with over 2 BILLION Euro debt and a stockpile of 300 thousand unsold bikes.

This doesn't fare well for the groups other brands like Gasgas and Husqvarna.

2 companies are in "talks' with KTM namely the Indian Bajaj and Chinese CFMoto.
CFMoto has had a business partnership with KTM for some years building small bore KTM badged bikes for the Chinese market and holds shares in KTM. The latest much upgraded products from CFMoto to hit the world stage are KTM so it would seem a foregone conclusion CFMoto would take full control if it chooses. February was the cut off for KTM to keep self managed so now we wait.

8

Tech Talk / Re: PVL Timing

« on: March 01, 2025, 10:08:02 am »

Walking is a reference to seals or bearings moving along the shaft if not secured. An alternative to a shim is epoxy.

9

Tech Talk / Re: PVL Timing

« on: February 28, 2025, 10:24:15 pm »

0.6mm "should" be okay if you use a sealant to stop the seal from walking and they do and can give erroneous readings. When testing remember no more that 8 PSI, any more and your causing problems as your over charging.

The working differential pressure tween the case and the created low pressure in the combustion chamber that rises the charge to the combustion chamber is much less like 4-6PSI unless its hyper charged like snowmobiles with superchargers or turbos. The expansion chamber reflection wave scavenging sucks a lot higher PSI though its effect is reduces the further its length. Once you get the bottom end solid you can think about the top end carburation exhaust and squish but it all starts with the bottom end being rock solid and without that your confusing errors. 

I work mostly with small bores and a wipe with Hylomar on all sealing surfaces is my go to if it needs it or not and has never caused me to double think and i rarely test bottom ends though you shouldnt be able to just push a seal in raw with your fingers and expect it to hold up at RPM.

Fairly obvious your sucking air and gearbox lube which points directly to the RH seal (or centre gasket/sealant) and you mentioned a rough surface on the seal journal which i cant comment on how it  occurred but I have suggested a possible go around with a sealant. Unsure how that happened as the japs are pretty good with machining though a shim loctited in the journal could be the answer if you feel the journal is beyond spec with its imperfections. One for you and you machine shop.

10

Tech Talk / Re: PVL Timing

« on: February 27, 2025, 08:11:37 pm »

Looks like you found the smoking gun. Grab the verniers and measure to ensure the seal is actually to spec and the cases.  Same as fork seals , if you soak them for an hour in oil they will soften and swell a bit but a better idea is a sealant. I use Hylomar though Yamabond should work okay or you could go via one of the Loctite  products like 648 retaining compound. You local bearing shop should have what you need so have a chat with them.

11

Tech Talk / Re: PVL Timing

« on: February 23, 2025, 02:16:48 pm »

Fingers crossed you get to the heart of the issue. One other place that air cooled big bores have leak issues is the base gasket Im sure i read on this site where a CR500 was literally eating them. I dont recall the fix for it  but it is an area to also look at.

12

Tech Talk / Re: PVL Timing

« on: February 19, 2025, 04:14:06 pm »

I take it you havnt cleaned up that head and its showing quite a lot of burnt oil on the EX side and that's all.  You also mention the heat and you mention you HAD Det issues before changing the squish. Difficulty in jetting ….. All those points lead to a bad seal even though you have mentioned a leak down test. The gearbox issue also mentioned  adds to the air leak argument being the root cause despite the leak down test. Nothing else will cause all those issues apart from an air leak. Changing to a lower octane fuel can have results but that's only done after the jetting is correct and its not plus it could mask other symptoms. Swapping out the ignition  wont do much unless its faulty. If it was my engine Id have the engine pulled down on the bench and reseal the centre gasket and throw a new pair of good quality seals in so I knew it was good  before trying anything more in the top end or electrical. best of luck with it.

13

Tech Talk / Re: PVL Timing

« on: February 17, 2025, 04:48:21 pm »

id leave the ignition alone. Heat issues are mainly fuel issues and you've said you have fuel issues. Fuel cools the crown so at a very rough guess your a bit lean on the main. Fix the carb issues first so you dont confuse the issue and i wager your heat issues will be no more. As for reading heat try it on the pipe as its far more accurate.

14

Tech Talk / Re: Spluttering When Rich - What's Actually Happening in There?

« on: January 11, 2025, 09:51:02 pm »

If you ever suspect a centre gasket or RH main seal you will get a smokey exhaust as gearbox oil will also seep into the crankcase ,The gearbox oil will be contaminated and look a bit milky and stink a bit.

15

Tech Talk / Re: Spluttering When Rich - What's Actually Happening in There?

« on: January 10, 2025, 08:41:33 pm »

Pressure isnt actually an issue in the bottom end of a 2T engine as the charge isnt pushed its sucked, either by the pressure differential created in the combustion chamber or pipe scavenging. Maybe a whole 7PSI in the bottom end at most so if it holds a 10PSI (never any more or you will blow a gasket or seal) in a test for 10 mins its good to go. As for the gearbox leak my thoughts would be over full or a blocked breather.

Sounds like that engine needs a lot of love whatever it is so back to basics. Pull the clutch cover and clean the old gasket and crap off it and pull the locating pins then hone it flat with a sheet of fine wet and dry on a sheet of window glass so you know its flat. Then a new gasket or yamalube as per the specific factory requirements.

Sorry dont mean to be rude and basic but I gotta ask so please forgive me and remember we dont know what you have as you havnt said (WHAT bike do you have) and we dont know your experience or the bike history so again please forgive if i have over simplified and stated the obvious. The only way a bottom end can build pressure to blow a gearbox seal is if it is or close to hydrolocking. Bad float needles and bad fuel taps drip fuel while the bike is sitting and "SH#T" all runs down hill and you end up with an oily premix filling your bottom end halving the area. It will still run sort of after coaxing but be a Biatch to tune and smoke more on start up than a 13 year old with a hard on with his skills trying to impress a new girlfriend untill it starts to clear a bit and still run like shyte.