forks

[bondy]

hi all how mutch oil do i need to put in my sherpa 350 forks ive got castrol 10w fork oil allso whats the best gearing ive got 11 tooth front sproket what should i get for the back? ive been tojd 39 is the standerd would this be ok for geting up hills? im onley just starting to trials so i wont be going up any great big mad hills not till i get use ive just rebuilt my sherpa 199A just wating to get my wheels cant wait to try it got it runing needs tinkering with but cant do mutch till i get the wheeels think the cluts will need setting im praying it wont need a new one but if it dose ill cross that when i get it running by the way is it easey to put new clutch plates on im thinking of getting the barnet ones if i need them would i have to get a clutch holing tool? Edited December 18, 2010 by bondy

[pschrauber]

Standard for the betor forks is 180 ccm of sae 30! each side of course.

Sprockets, front with 11 teeth is OK = standard, back, yes standard is 39 teeth.

You can get parts for clutch de- and reassambling thru Bultaco UK for example.

[bondy]

Standard for the betor forks is 180 ccm of sae 30! each side of course.

Sprockets, front with 11 teeth is OK = standard, back, yes standard is 39 teeth.

You can get parts for clutch de- and reassambling thru Bultaco UK for example.

hi the oil ive got is sae 10 says in the manual 106ccm in each leg will this be ok? allso how would i wire a second condeser under the tank and whats the best way to clean the points i got a littel igniton file its not dead rough will that be ok? thanks bondy

[woody]

106cc is not enough, did you mean 160?

The Bultaco forks take a bit less than other bikes with Betor forks so between 160 and 180cc is a benchmark for starting with. SAE depends on personal preference. Bulto forks aren't exactly the best in the world and even with 180cc (and more...) of SAE30 they can still top out. As you've got SAE10 already, use that and try 160cc to start with and add 10cc at a time if you think they need it. Once you get towards 200cc though they will start locking through too much oil

[triple_x]

Hi

I use 5 weight in the winter and 15 in the summer.

That's what Sammy Miller told me and it seems to work!

Regards tha amount, well I put in the amount speced in the manual and just kept adding a touch more until they softened out at full compression without bottoming.

Just trial and error but beware too much will blow the seals.

I can't ride for toffee but the front end certainly improved as last season progressed.

Regards

Martin

[bondy]

106cc is not enough, did you mean 160?

The Bultaco forks take a bit less than other bikes with Betor forks so between 160 and 180cc is a benchmark for starting with. SAE depends on personal preference. Bulto forks aren't exactly the best in the world and even with 180cc (and more...) of SAE30 they can still top out. As you've got SAE10 already, use that and try 160cc to start with and add 10cc at a time if you think they need it. Once you get towards 200cc though they will start locking through too much oil

hi yes i ment 106cc in each leg thats with the sae 10 thats what it says in the work shop manual i got from bultaco uk. is sae a higher spec fork oil is that why i need less im just gessing

[bondy]

106cc is not enough, did you mean 160?

The Bultaco forks take a bit less than other bikes with Betor forks so between 160 and 180cc is a benchmark for starting with. SAE depends on personal preference. Bulto forks aren't exactly the best in the world and even with 180cc (and more...) of SAE30 they can still top out. As you've got SAE10 already, use that and try 160cc to start with and add 10cc at a time if you think they need it. Once you get towards 200cc though they will start locking through too much oil

hi yes i ment 106cc in each leg thats with the sae 10 thats what it says in the work shop manual i got from bultaco uk. is sae a higher spec fork oil is that why i need less im just gessing

[woody]

SAE refers to the grade / thickness of the oil so SAE5 is thinner than SAE30. The thinner the oil the faster the damping piston will move through it, like trying to move your hand through a bath full of water as opposed to treacle. The forks will compress and rebound quicker with SAE5 than with a higher SAE.

The SAE has no direct bearing on the quantity of oil used, or not that you need to worry about. The recommended quantity for the Bultaco is 160cc. They have a shorter fork leg than most other bikes. However, it's only a recommendation and there is tolerance to use more than that. Use your SAE10, start with 160cc, take it from there and add 10cc at a time if required, but 200cc is the absolute maximum

[evo boy]

Hello all, I'm just about to change the oil in my sherpa forks as I'm not sure if they have ever been done. My weight is around 14 stone what oil would you recommend? I was going to try 180cc in each leg.

[bullylover]

I use 180/ 190cc in all of mine, I have a M159, M199 and a M199B that has I think M151 forks on it. The B also has Italjet Betor damper rods in it. That was to stop them topping out like crazy. I`m in Australia so I find 15 weight suits me and the conditions over here but we don`t have the cold that you do in England. I saw somewhere on here that Sammy Miller used to recommend 5 weight in winter and 15 weight in Summer which sound about right to me. Graham.

[evo boy]

So when you say 15w that's proper fork oil as I've Hurd people putting atf and even engine oil in them.

[sherpa325]

Back in the 70's when these bikes came out it was impossible here in Australia anyway to buy different weight/viscosity fork oils, so everyone that I knew used ATF - 180cc. If the fork topped out [clunked when doing a wheelie] just add another 10cc until it stopped. I have tried the newer fork oils in my Bultacos and I feel they are too light for forks built in that period, so I just continue to use 180cc ATF with no problems. I am very fussy about the setup of my bikes and for example I use 2.5 weight in my 300 Gas Gas as the current forks are sensitive to the modern fork oils.

Cheers Greg

[2stroke4stroke]

There's also the factor that a modern fork action is not what the original specification was intended to produce so experimentation may be necessary to suit individual requirements.  

[evo boy]

2 hours ago, sherpa325 said:

Back in the 70's when these bikes came out it was impossible here in Australia anyway to buy different weight/viscosity fork oils, so everyone that I knew used ATF - 180cc. If the fork topped out [clunked when doing a wheelie] just add another 10cc until it stopped. I have tried the newer fork oils in my Bultacos and I feel they are too light for forks built in that period, so I just continue to use 180cc ATF with no problems. I am very fussy about the setup of my bikes and for example I use 2.5 weight in my 300 Gas Gas as the current forks are sensitive to the modern fork oils.

Cheers Greg

Thanks Greg I'll try 180cc of ATF in each leg and give that a go.