Factory 3.0 kit - spring query

[Zanderk]

Hi guys,

Firstly, I have read through lots of posts concerning the Factory 3.0 kit and I have looked at the carb jetting database (v useful) so I’m not asking because I’m lazy.

Do you have to stretch the carb springs to get the best out of the fitment or have some people fitted the kit without stretching them ?

You see I like to make mods that are reversible i.e I can just swop back to the original part if I put the bike back to standard. The carb springs are listed as ‘no longer available’ by stockists I’ve checked with, CSNL have 1 left. So I’m pondering about whether I stretch and bake them or just leave as is.

Thanks in anticipation.

[JackalHack]

I did the stretch and bake to the 8" recommended length - as far as wanting to have changes be reversible, I started out thinking that way also but have subsequently abandoned that thinking. I found myself asking why I would want to go back to stock if I am working on making improvements... After what I have changed, I can't see me ever going back to stock/street configuration.

[bk94si]

I went for years without stretching the springs. I finally did do the stretch and bake though. Truthfully, I couldn't really tell any difference myself but I am a pretty non-aggressive rider.

[ParcNHawk]

If you're not an engineer, you follow the engineer's directions.

[Zanderk]

[QUOTE=ParcNHawk;n972039]If you're not an engineer, you follow the engineer's directions.

I hear you. Not an engineer, but I am an scientist (meteorology, plant physiology) and that’s taught me to consider, question and observe scenarios. So I’ll wait till I can source a spare set and I’ll do a back to back

[Tripleman]

I went for years without stretching the springs. I finally did do the stretch and bake though. Truthfully, I couldn't really tell any difference myself but I am a pretty non-aggressive rider.

Agree with that,I have one set in stretched and another set in spares. Didn’t notice any difference,but then I’m no speed freak,more old fart.

[Zanderk]

Agree with that,I have one set in stretched and another set in spares. Didn’t notice any difference,but then I’m no speed freak,more old fart.

Yep, that’s my thoughts on this one. Getting parts is tricky sometimes but then that’s the rub of owning a 30 year old bike ! I thought I had it covered with some 650 Bros carbs but when I pulled them apart yesterday, they were very different (smaller diameter spring, different length, etc), leading me to the assumption that they may not be 650 carbs at all (maybe 400 ones). You live and learn.

[rpcraft]

I will probably get some ulgy stares for saying this, but I just stretch them now days and do not bother with baking to "lock them in". Once a year or so I take the carbs apart and I just haven't noticed them getting shorter from lack of annealing so I figure somene was using precaution and good advice to include that information but if I am going to fire up the oven it better have cookies coming out of it aftewards.

I digress, I am not an engineer, just a guy who has done it on multiple carbs on multiple bikes and the stretch and no bake method has always been fine for my purposes.

400 carbs seem they would be mostly the same from what I have read but being state side I have never had a set on my bench to compare. It would not suprise me to know the springs are different, as well as the jetting I am sure. Beyond that i am not sure the needles would need to be and I would be interested to know if they still use the 42 slow/idle jet.

[Talon]

400 carbs seem they would be mostly the same from what I have read but being state side I have never had a set on my bench to compare. It would not suprise me to know the springs are different, as well as the jetting I am sure. Beyond that i am not sure the needles would need to be and I would be interested to know if they still use the 42 slow/idle jet.

35 or 38 depending on the year.
88 & 89 use 35.
90 uses a 38.

[yorkshire]

I have 400 carbs, the difference I have noticed is the choke slide is flat at the end and does not have a needle, which 650s do

[Zanderk]

Today I was particularly nervous to take ‘a bit’ off the needle retainer when fitting the factory 3.0 kit so I approached it a bit like this….

https://youtu.be/69MpLiYhsXw

[Zanderk]

I have 400 carbs, the difference I have noticed is the choke slide is flat at the end and does not have a needle, which 650s do

Thanks for the info, appreciated