I started this thread in the old forum which can be found here http://www.400greybike.co.uk/oldforum/t ... C_ID=70540

What i want to know is the 0.5mm shims i have, do i add them to the shim thats already on the needle or do i replace it with the new one?

You would add it mate :D

finally got round to fitting the shims, springs and jets today, first i tried just fitting the 110 jets in the back 2 carbs only as sugested by viper.
Bike pulls well but still hesitates every worse now

Then i tried 110 jets all round, Still hesitates but its better. Its worse the longer you ride it hard. It seems to fly through 1st and 2nd and then hit the flat spot.

I dont have any more jets yet so tried fitting a baffle to the can but that made little difference so now the standard jets are back in and the stanard can will have to go back on tommorrow

For the people that know is my next step just to keep going up a jet size all round or just the back 2 first to try and get the fueling right?

It seems strange that a end can can mess the fueling up so bad

Send me a detailed list of everything you have and have done to the bike and i will try and help you out, to be honest you will need to get it on a af meter. I have done tons of these bikes and there is no magic figure for set up, all bikes burn that little bit different. The original set up described in the manual is a best comprimise which that is all it is a compromise that helps in all areas any alterations upset this.

Thanks chris, im not after a perfect setup i just want to get the bike rideable as the mrs refuses to ride it unless i put the can on.

The bike is pretty much standard engine wise apart from the scorpion can and the airbox scoop has had the foam removed. i do have a hrc air tray to be fitted tho. And at present the standard 108 jets are back in and so is the standard can. I assuming the bike will be running fine in standard trim but as i didnt get it back together till late last night i havent had time to test it. i will this afternoon tho.

oh and ive just fitted the hrc slide springs and a 0.5mm washer under the needles which has made a huge difference to the midrange pickup.

Hope you can help

start with a correct air filter and fit the air scoop back with all surrounding part of the tray in tact your exhaust isnt your fault removing the scoop is the best thing to make your bike run like crap plus i have seen filters with the element cut away and foam stuck to them, the outcome of that was smaller jets still to get them up to speed proving that the foam element was more restrictive. I take it all bellmouths are stock lengths? Fit either 110 dj or similair main jet or 112 kehin jet all round (front cylinder will be a little richer at that but it helps comprimise on flat spots) fit 1 0.5 shim under each standard needle, providing slides havnt been tampered with and are drilled to original size the hrc springs you have will work fine, at engine temperatures below 60degrees thes bikes have flat spots make sure your up to temp before trying out.

ok quick update, i just took the bike out and it still hesitates, its just less noticable with the standard can on, it seems ok when not using full throtle and the hesitation is worse at higher revs. In fact yesterday when i had the 110 jets fitted and scorpion can the bike actually pulled much harder than it does now in standard trim, thats when it wasnt hesitating!!

Spose i should also mention when i brought the bike last year it was in restricted form by means of the washers in the carbs, these have been removed and i understand that was the only way the bike was restricted.

I did have the bike stripped down over the winter but didnt touch the carbs although i can accept that the problem probably lies within the carbs.

The air filter is brand new OEM honda
The air box is totally standard apart from the foam in the snorkle has been romoved by myself due to a recomendation on the old site somewhere.
I have already fitted the extra 0.5mm shim on the needles as well as the HRC springs. Viper said i would not need to drill the slides as its an RVF and that the shims and springs do the same job.
Im assuming the slides are standard as the bike didnt look like it had been messed with before although im unsure how to check if they are standard.

Are there any other common problems that cause hesitation? maybe electrical? reg/rec?

It will likely be lean.


Try bigger main jets (112+).

One thing i thought i might add after reading another post, i have removed the rubber flap that sits in front of the carbs in the V piece of the frame, i removed it to fit a HRC tray but the tray needed trimming to fit properly so i decided to fit it at a later date and didnt bother refitting the rubber flap.

Ive read that removing this flap disturbs the air flow and will upset fueling, can anyone confirm this as this will explain why after fitting the shims,needles,springs and 110 jets the bike pulled really well but had a pretty bad hesitation the faster i went.

Well ive just got in from the garage after returning everything to standard, needles,shims,springs and jets, ive lost count of the times ive had them carbs apart over the last couple of days to get this right and now im thinking its all down to this rubber flap i removed when i first started messing with it.

Yeah you need the rubber flap in there, check the other current post about hesitation issues.

Generally when the bike runs fine in lower gears, worse in higher gears it will be a fuelling issue (either too much air or too little fuel).


Yours will probably be a combination of main jets that are too small and missing flap.