5 replies to this topic

[Dave_Askham]

I have been fortunate enough to get lumbered with servicing my mates bike, it has a few issues, mainly around being choked up and overheating like a good un !!!

It resembles a steam engine more than a trials bike, but I currently have it in a million pieces and have a few questions that I am struggling to find the answers to, I thought that the power of the internet may come to my rescue once again and that I would ask the questions on here for assistance from people power.

I have stripped the bike to allow me to de-coke the exhaust system, and whilst doing so I noticed that the inlet manifold on the bike has a spacer between the reed block and the crank casings, I wondered if this was a standard item, or an aftermarket spacer presumably to soften the power??
If anyone has a bike of the same type, can they take a peek and see if they have the same??

Also, I am not sure how much engine oil is used in the bike, I have looked up and find conflicting advice between 650 and 750ml, can anyone clarify?? Also, where do you pour the oil in??? do you remove the oil level window / bolt??? Forgive me if I am being stupid, only I can’t find a filler cap anywhere !!!!

With regard to the overheating, the fan works when up to temp, but the bike has just blown it’s load and p*ss*d water / steam out of the overflow on the rad, the water pipes were all OK but it clearly was not happy, It was stopped immediately, and left to cool, the compression appears to be OK and the oil has not emulsified. has anyone got any advice on what to look for on this model??

Thanks in advance for any help / advice you can give, if you need any more info, please ask.

[JSE]

"I have stripped the bike to allow me to de-coke the exhaust system, and whilst doing so I noticed that the inlet manifold on the bike has a spacer between the reed block and the crank casings, I wondered if this was a standard item, or an aftermarket spacer presumably to soften the power??
If anyone has a bike of the same type, can they take a peek and see if they have the same??"

The spacer is standard, it: spaces the carb bowl off the engine cases, makes the intake tract slightly longer for smoother bottom end power (and various other things that are barely noticeable).

"Also, I am not sure how much engine oil is used in the bike, I have looked up and find conflicting advice between 650 and 750ml, can anyone clarify?? Also, where do you pour the oil in??? do you remove the oil level window / bolt??? Forgive me if I am being stupid, only I can’t find a filler cap anywhere !!!!"

Between 650 and 750 is good. Factory recc.'s are for 750, we usually ran 650 for a little better clutch action. Either will work. There should be an aluminum plug by the kickstart shaft on the sidecase but a lot of riders lay the bike on it's side, take off the clutch cover off and pour the oil over the clutch pressure case.

"With regard to the overheating, the fan works when up to temp, but the bike has just blown it’s load and p*ss*d water / steam out of the overflow on the rad, the water pipes were all OK but it clearly was not happy, It was stopped immediately, and left to cool, the compression appears to be OK and the oil has not emulsified. has anyone got any advice on what to look for on this model??"

First guess is that the inner head o-ring is leaking which will still give good compression under kickstarting but much higher exhaust pressure will pass by it into the coolant and give the symptoms you describe.

Jon

[Dave_Askham]

Hi Jon,

Thanks for your speedy reply, I didn't notice that the carb bowl would catch the casings if I removed the spacer, but it makes sense now you say it, my mate is just getting back into trials after a long lay off, so he's not in need of ultra sharp throttle respose and wicked torque etc, I'll be leaving the spacer firmly in place !!!

With regard to the head o-ring, I will pull the head off tonight and take a peek, I assume I should see some evidence of the leak?? even though the bike has hardly run since this occured I assume it will have left some tell tale signes that it's gone...

As for the oil filler, I thought If I could not find the filler cap, I would lean it over and pour it right in the clutch directly, would you recommend any particular oil?? the oil in it is PINK !!!! I have ridden for years and never seen pink oil... I was thinking of popping some Putolene light gear oil in it like I used to put in my Mont 315R, it never did it any harm.....

also seeing as you appear to know your stuff, do you know the fork oil weight and capacity for this bike as standard, I was going to go with 5wt as it feels a bit unresponsive at the front to me but I am not sure of the capacity.....

Thanks again for your help.

Edited by Dave_Askham, 14 June 2010 - 02:59 PM.

[totalshell]

all you ever dreamed of..

http://www.trialspar...a.com/tech.html

[JSE]

Dave_Askham, on Jun 14 2010, 09:59 AM, said:

Hi Jon,
Thanks for your speedy reply, I didn't notice that the carb bowl would catch the casings if I removed the spacer, but it makes sense now you say it, my mate is just getting back into trials after a long lay off, so he's not in need of ultra sharp throttle respose and wicked torque etc, I'll be leaving the spacer firmly in place !!!
With regard to the head o-ring, I will pull the head off tonight and take a peek, I assume I should see some evidence of the leak?? even though the bike has hardly run since this occured I assume it will have left some tell tale signes that it's gone...
As for the oil filler, I thought If I could not find the filler cap, I would lean it over and pour it right in the clutch directly, would you recommend any particular oil?? the oil in it is PINK !!!! I have ridden for years and never seen pink oil... I was thinking of popping some Putolene light gear oil in it like I used to put in my Mont 315R, it never did it any harm.....
also seeing as you appear to know your stuff, do you know the fork oil weight and capacity for this bike as standard, I was going to go with 5wt as it feels a bit unresponsive at the front to me but I am not sure of the capacity.....
Thanks again for your help.

In a 12 year old bike, heat cycling will slightly compress the copper washers under the head capscrews unless they are re-torqued now and then (which lessens clamping force), which is why the o-ring is my first guess considering the symptoms you describe. You will probably see indications of exhaust gas leakage but not always. Be sure to grease the o-ring before installation. Pink oil indicates a worn water pump seal (Dexron and coolant=pink). If the seal is worn, on this bike, I'd also replace the water pump shaft also, based on the bike's age, it probably has a groove in it from the seal lips and replacing the shaft and seal as a unit will extend the repair greatly.

Another possibility for the pink trans oil is if the overflow tube coming off the radiator cap is squashed or plugged (or the pop-off valve in the cap reacts at a too high temp/pressure), the excess pressure in the cooling system will force coolant past an otherwise good seal. You might want to fix the o-ring first (assuming that's the problem), change the trans oil and check for pink oil again to be sure the seal is another problem to be dealt with.

A lot of riders run Dexron ATF in the trans with very good results, change it often and the engine will benefit over time. You'll want a light gear oil in a Trials transmission.

300cc's of 5 weight fork oil in each fully drained leg. If you need a little more damping use Dexron ATF, which is about 7.5 weight and has all the necessary additives and properties (anti-foaming agents, good lubricity etc.) that work as fork oil.

Jon

[Dave_Askham]

Hi Guys,

Just a quick one to day thanks for your help and advice regarding my difficulties with the Gasser, I spend a few evenings sorting the problems and we were out yesterday and the bike ran as sweet as a nut !!!

after some fun and games de-coking the exhaust and repacking, it's now like a new bike, we just need to teach the rider a thing or two now and all will be well.

So thanks once again for taking the time to assist, your help is Mucho appreciated.

Dave