Help! Problem refitting injectors

[MartDude]

Hi, I could do with some advice, please.

I'm replacing - or trying to replace - the injector o-rings on my '89 K100RT. And I'm having trouble in getting the injectors back in to their housings on the fuel rail - it takes an unexpected level of force to get them in, and I'm finding it difficult to get them in straight; I've already damaged 2 o-rings. Is there a special technique for this operation? I'd lubricated the rings with fresh engine oil.

If it's this hard on the bench, how will I get the injectors properly seated in their housings in the head?

The new o-rings came from a reputable supplier - MotoBins - so I'm sure they're the correct item.

When I removed the injectors, instead of the injectors & fuel rail coming off together, the fuel rail pulled off, leaving the injectors behind. The injectors themselves where a real pig to get out - required a lot more force than I expected - resorted to levering them out with a pair of cranked long-reach pliers.

Thanks in advance.

[frankenduck]

Did you put a thin coat of engine oil or other lubricant on the O-rings prior to trying to install them?  That's what I do.

[MartDude]

Did you put a thin coat of engine oil or other lubricant on the O-rings prior to trying to install them?  That's what I do.

Yes, I did; fresh engine oil.

[frankenduck]

Hmmm...  got me.

When installing them back into the engine block I use a block of wood and a hammer on the fuel rail to GENTLY tap them back into place.

[MartDude]

Hmmm...  got me.

When installing them back into the engine block I use a block of wood and a hammer on the fuel rail to GENTLY tap them back into place.

(Tried to reply earlier, but there seemed to be server problems)

Aha! I'd just been contemplating this technique.

I'm perturbed/puzzled by what seems to me to be the excessive force required to get the injectors in to their housings; the Haynes & Clymer manuals suggest they just push back in easily, while the threads here & on other forums barely hint at the problems I'm encountering.

[frankenduck]

While they may be "new" from the seller, they may have sat on the shelf for a while and hardened.  Try something like ArmorAll on them. That might re-soften them and it also can make rubber very slippery.

[ljjohns]

I didn't check the parts numbers, but we found, for our K11LTs, that this was a cheap and easily obtainable substitute: the 0-rings for the fuel injectors on a 1990 Mustang 302 c.i. engine gauge out the same as the new ones Mr. Injector had installed. And they were available for $2.89 for four at a local auto parts store.

Larry Johnson

[jetpoweredmonkey]

I just did this job on my K100RS using the o-rings below.  They were easy to fit and pushed in without much force after lubricating them.  If you have a caliper handy, you might compare the new vs. old just in case they gave you oversized ones.

FWIW, the "blue" are supposed to go to the fuel rail, the "brown" go to the head.

http://www.euromotoelectrics.com/Fuel-Injector-O-ring-13-64-1-437-474-p/boinj-oring474x8.htm