RB20 fitment issues.

[10 inch Terror]

Blimey it feels like I've just been told off by the headmaster for wearing the wrong uniform.
The reason I used the MB studs on this build is because they were fitted to two engines previously built for me by a tuner with a very very good reputation. I thought if they are good enough for him who am I the question them. I have refitted the original studs to the casing and although the barrel went on slightly easier it is still a rather snug fit. I'll order some new standard SIL ones from scooter restorations and save the MB ones for another day. Thanks for all your input chaps Pete.

[Timbo]

......and don't do it again......

[Adam_Winstone]

^... sorry, that wasn't my intention in the slightest! That must have come across as my stern voice that I keep special for role play with the wife!

The only reason why it may have sounded slightly harsh could be a tone of frustration, not with you but simply because this is an issue that has come up a number of times before and the more that 'fat' studs get used as seemingly sensible replacements for old rusty originals, the more and more common this issue becomes. The last couple of times I have had to try to get the point across that fitting 'fat' studs often introduces the problem and that it is IMO wrong to defend their use by blaming the kit. Like I said, these can even give issue with certain unfortunate matching of standard factory parts... and surely it has to be wrong to introduce these studs and then try to blame Innocenti and Serveta for not making their parts correctly (?).

What is a result is that by addressing the issue you are far less likely to apply the side loadings that can cause the spigot to crack/fracture in use and cause you expensive, and unnecessary, problems in the long run.

Sorry if the tone came across wrongly, I meant to sound more positive

Adam

[10 inch Terror]

Ha ha I meant it in a jovial way and no offence was taken. Your replies are very well written and you obviously spend a lot of time on them and for that I'm very grateful. Please keep up the good work and thanks again Pete.

[camel]

what a brilliant summary Adam.
ive just embarked on a new engine build with a self converted 150/200 case and had the same problem,i intially thought id maybe machined the stud holes slightly wrong but through a process of elimination i found the barrel to be binding on the extra diameter of the "fat" studs,ive skimmed the studs down a tad and partially drilled an oversize hole down the barrel studs too...
strangely im glad someone else has had this problem...i thought i was going mad..

[Adam_Winstone]

"strangely im glad someone else has had this problem", this reflects the fact that the more popuar these studs become, the more people are running into this problem . Hopefully, others will read this too and avoid making other unecessary modifications and/or damaging their expensive kits/casings.

Adam

[tonydevon]

roll threading is also possibly a stronger thread anyway, so it makes sense to use them if they also avoid clearance and sideloading issues

[ducksta]

the frustration is another product comming to market not fully researched, and left to the scooter fraternity (adam and co, well done)to put right.

[Ian Hepworth]

the frustration is another product comming to market not fully researched, and left to the scooter fraternity (adam and co, well done)to put right.

Sorry but I can't let that go. The MB studs are a direct copy of P200 studs apart from being a little longer and the lengths of the threaded ends are different lengths.
They are not rolled. P200 studs aren't rolled in the proper sense of the word (as in the shank of the stud is smaller than the threaded part). The small block px125 etc ones are.

If you look back along this thread you will see people saying things like used the standard studs but it was still tight.
Even adam admits there are two kits from two different manufacturers that he often has problems with.

MB sell 100s if not 1000s of cylinder studs. They are one of our best selling items. It would follow then that we get loads and loads of complaints about based on the above - sorry but we don't. There have been literally a handful and when you ask what kit is being fitted it's always the same replies.

If people are damaging spigots then they are being heavy handed during builds - building an engine is engineering - the solution isn't to get the hammers out.

[MB group]

Adam once again your are clouding peoples minds to cylinder studs, how wrong you are. Ok in certain aplications (not Lambrettas) a real designed stud maybe thinner along its length in certain applications. Certain Lambretta cylinders are machined incorrectly on the stud holes and in the angles they are machined, so are engine casings, don't blame a designed stud and ramble on and on when your not qualified to do so. Our studs maybe straight, they are certainly stronger than any rolled studs supplied into the market, they can be used with shortened cylinders, extended cylinders and cylinders using a packing plate or head gasket. When fitted they sit in the casing correctly with no threads exposed to lock onto a cylinder or gasket. Cylinders machined correctly for example like the RT, TS1, SIL, Innocenti cylinders fit perfect, very easy and slide straight down, (there will be others). Some cylinder may fit one casing correctly try the next casing and it doesn't fit. If you had been in the profession as long as we have you would know these simple facts. I think it's time you gave up with our one horse crusade to get people back onto inferior standard studs which caused us grief for many years, they snap, they stretch and are not long enough to be as versatile as our studs. What do Vespas fit? Straight shanked studs which help to locate the cylinder nicely, with the amount of TS1/RB/Rapido and other cylinders where casings are ported to suit the cylinder? but if people want to go back to the dark ages and fit standard Indian studs becasue one person think they are the best, please feel free!

Mark