In removing the TB's and injectors the first thing that was apparent, aside from the er.....intricately hand-painted finish on the injectors was the fact that the clips to secure the them to the fuel rail were missing. As the fuel rail clamps them to their inlets I'm not sure if this is a huge problem, although I will replace the missing clips.



Onto the injectors themselves, despite their appearance they seemed to work okay but aside from renewing the seals what is the extent of their serviceability?

As I'm upgrading to the 35mm TB's and although I read that retaining the standard 8V injectors suits this mod, I've also read some info on later type injectors (16v ones??) having 4 point fuel squirt (improved atomisation?) rather than the single squirt that the standard injectors supply. However I then drowned in ohm and fuel poundage data and became confusingly embroiled in Ford, Denso and Bosch cross reference numbers but which, when correlated against the data in this table, http://users.erols.com/srweiss/tableifc.htm clearly have different characteristics and I'm not sure what would make a better/cheaper alternative.

I guess I am looking to replace the tatty examples as shown and spending the budget wisely to maybe achieve a little performance gain in line with the bigger TB's without degrading the original driveability of the bike.

Can anyone offer suitable advice??

Thanks

Fent

I'm sure someone on this forum (US or Canadian based) cleans and then tests them on a flow bench for very little cost.

Try a search.

RobinW wrote:I'm sure someone on this forum (US or Canadian based) cleans and then tests them on a flow bench for very little cost.

Try a search.

Search "Rjtrucker".

The first link is probably the best for the OP as he is in the UK. Why order from the US or Canada when the postage will add a huge amount to the cost?

Cos that's 50 bucks for a new one or 16 bucks for a refurb. Times four. How much is post?

Thanks all for jumping in.

It was actually advice on which injector to use I was really after. I started cleaning mine up but the bodies are incredibly corroded although I suspect it won't affect the functionality Im still going to change them. So  a new/refurb/decent second-hand set are the order of the day.

Duck thanks for the link to UK Mr Injector. Do you know if those are the 4 point fuel squirters (0280150715) I talked about in my original post?? If so they flow slightly more fuel than my standard injector but also require 43psi to operate against the standard 36 provided by the K100 Fuel pressure regulator (according to the data table linked in my first post). I don't know enough about the different injectors to make an informed decision as to suitability. So unless I can get a definitive response I'll stick with the original injector spec.

Robin W its not always the post charges you have to consider there's also UK import VAT (tax) at 20% if the value of the item exceed $30. On that basis the Mr Injector prices are quite reasonable.

Cheers

fent

http://www.osidetiger.com/Pages/default.aspx

K-rider

at a guess ...you might increase the flow by 4 or 5 % with the throttle bodies change over
the stock afm will compensate for that quite well , still using the standard injectors

does someone have the bosch part numbers for the 1100 injectors

like you I am still looking for multi point ones ...although blakey and a few others have found a supply here in aussie of the 4 point types ...haven't read the flow ratings of those ones yet ..(need a part number) apparently out of a v8 gm motor ?? (but im still suspicious that the delivery will be too high for our machines )

but worth investigating

keep us up to date fent

Fentible wrote:
Robin W its not always the post charges you have to consider there's also UK import VAT (tax) at 20% if the value of the item exceed $30.

Strike that's pretty mean, $30. It must cost them more to collect it than they make from it. It's $1000 here.

I believe all Bosch injectors are measured @ 43.5 psi.

I have the L-Jetronic system on my '83 280ZX Turbo and the injectors are rated  @ 43.5 psi, but the FPR is set @ 36psi.

I believe all L-Jetronics FI systems have this as the idle PSI for fuel.

Of course since mine is a turbo there is a different fuel pressure regulator that references boost.

To make a long story short, I don' think you have anything to worry about if the injectors are somewhere  around 14.8 lb/hr.

Cheers for that Brad-man. You are right regarding the 43.5 psi. I hadn't realised that all the injectors are tested at that pressure for comparative purposes. You can use the calculator on the Stan Weiss homepage to calculate the flow rate at 36psi of any particular injector

I came across this video which compares the single and 4 hole injectors

https://www.youtube.com/watch?v=bHf-6ohkgbA

I've also just emailed  a UK injector specialist www.injectortune.co.uk for their advice so I'll report back when I get a reply.

I run reconditioned 715 injectors in a K75 and two of my K1100s with a decent amount of miles on them now and they work fine.  Yes, they have four hole pintle caps.

I have not noticed any significant mileage improvement nor do they register on the ole butt dyno when riding.

This seems to be a popular mod among the Jeep crowd.  However, despite lots of Googling I was never able to find any apple to apple dyno results to prove if there's a performance improvement or not.

In THEORY, a "mistier" fuel/air combo should burn better but I have yet to see any hard data to back that up.

A link to a heap of bosch injectors, not by any means all but as I get info I add to it.
https://www.dropbox.com/s/bstcio2l0g2xi0c/injectors.pdf

It takes a bit of searching to find an injector that is a bit leaner or richer and you will notice that many are quoted in 2 and 2.5 bar pressures but from what I can gather any new injectors are quoted at 3 bar/46psi and cc/min

On an 8V K100 at or near sea level the 150cc/pm K1100 injectors leave a bit of extra black smudge at the exhaust tip as compared to the 133cc/pm K100 versions, using 35mm K11 TBs over the stock 8V's 33mm TBs. Mileage went down ever so slightly (negligible), and that might be explained by less judicious use of the right wrist due to the meatier midrange and upper RPM urge the larger TBs provided. Never was there a question of 'too lean' using the stock injectors, but I had to try it. I will go back to the stockers at some stage; there's no need for more fuel as plenty is provided for by them even with the 2mm larger diametre bore K11 TBs. If the exhaust and airbox were 'opened up' and a port job done, then this might necessitate the larger flow injector for an 8V with K11 TBs.*



*Factory air filter, stock K100 8V FPR and Motad exhaust.

Duck, Rick G, TWB - thanks for those replies especially the real world experiences.

I got the following response from James at Injectortune.co.uk


"Hello George, thank you for your email.
We don't have any K75/100 injectors in stock but can supply a replacement.
The 715 injector has a single hole pintle and identical spray pattern.
We can supply 4 x 4 hole injectors which are a direct physical replacement for your own injectors for £120 including postage and reconditioning.
These injectors spray a fine, conical mist (not a v pattern) and are a considerable upgrade to the OEM K100 injectors."

 
James seems to suggest that the 715's have single hole pintles. Im going to ring on Monday to clarify but I will likely go with their 4 hole injectors depending on the cc/pm. I tend to agree with TWB that the flow rate of the 8V K100 injectors is sufficient for the 35mm TB's using K100 standard heads and airbox.

Will keep you posted.

I think the 715s are single pintle.  My bad.

Ask the FI guy about 0280150415.

Hmmm... here's something else Bosch I stumbled across.  It's a single pintle cap but has a disc with four holes in it.

Hi Duck

From my understanding that disc is what distinguishes the '4 hole' injectors. The 4 hole disc creates a conical mist rather than a V jet of fuel leading to better atomisation and hence improved detonation of the air/fuel mix.

Fent

I am going to weigh in here on something I know nothing about (but that never stopped me).
As our injectors do not inject straight into the cylinder, does the reduced atomisation of the fuel make that much difference?
My understanding is that as all injectors fire at once, the 'closed' cylinders fuel will sit for a milli second before it is sucked into the cylinder.
My guess would be that sucking would disturd the fuel enough along with the added heat as it sat unburnt would be the same or close to having it sprayed as 4 small jets and then going through the same process anyway.

Claro?

Feel free to discuss.

(Yo hablo Espanol.)
or is that Italliano?

You might have a point Rossko, short answer is I don't know either and it may well be that this upgrade (?) would only be useful to someone looking to extract the last ounce of power in line with a host of other performance enhancing (expensive) modifications.

I guess for me, as I need to renew my current injectors anyway then replacing the standard ones with these won't, I hope, be detrimental, may give a slight boost and give me a head start on any future changes I may want to make. 

All the very best for 2014 to all forum readers and contributors

Cheers

Fent

good point rossco .....

but just consider that that jet of fuel is directed at the opposite side of the inlet port ..and to my way of thinking and as you say just sits there til an open event happens ..I recon in some cases this jet is more a stream of raw fuel that saturates the inlet port rather than atomising properly ...thus lowering the efficiency of the draw and finally the compression and burning of that mixture


I recon that we could well see an improvement ....not saying that there is anything wrong with what happens currently ...just recon there has to be a better way with what has happened over the last 30 years and the new devices that are available nowadays

I don't think there is any proof that there is a great difference ...yet

but not many of these have been retrofitted to older designed systems like ours ...possibly they just don't appear on the radar of performance folks ????

Scheffers was looking into the 4 hole injectors, but he stopped posting before he said how well they went.

From the burnouts he does, one may suspect they do quite well.

Could also be from the reduced weight from his many mods or it could be he has tyres to burn and is more willing to try to destroy them than the rest of us are.

If I could get mutli point injectors I would still give them a go.

I came across someone on one of the Kawasaki sites I visit and the writer said that he fitted six new 4 hole injectors to his Z1300 and it did feel better to ride but he did expand on that saying was it just because there was an improvement that he would have got if he had just cleaned his old ones or was it an improvement over the OEM.
he promised to keep us informed so if I hear any more I will pass it on.
See I have more than one passion in my life. I have been tossing ideas around over there about making a 6 brace of injectors from 2 sets of 38mm K1200 and use a Megasquirt system.