Hi all,

I have a fuel filter in my MC21 (between tank and carbs) and am about to switch to pre-mix. Are these filters okay to use with pre-mix or will they "suck up" some oil before the fuel gets to the carbs?

Thanks,

Jae

why are you goin to pre mix?
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Honda nc23 CBR400 AERO 1986, 1990 honda NC23 Tri-Arm, 1987VFR400 NC24 Rothmans Rep, NSR250 MC16 1987, CL250s 1983. Moto guzzi zigolo 110cc 1958. Fantic 50cc 1972. Suzuki Cobra Race bike 500cc 2t 1975 , GP125 1975. Triumph T110 1954. BSA Thunderbird 1955. Ariel VB 600 1952, 1990 MuZ 125 etz.

I have run fuel filters on premix NSR's without trouble. However, I would buy clear ones. I like to know whats going on.
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If I have to take the carbs off once more...

Good call Steve. And use the biggest filter you can get away with, and don't be a cheap skate. Buy the best you can.

I got fed up with trying to adjust my injectors and I probably won't try to register this bike for the street so...
I spent the first part of my track day with too much oil from the injectors, fouled my plugs and when I adjusted it to the recommended "mark" on the injector rotor, there was too much slack in the cable so I got worried about not enough oil at lower throttle settings. I think I have an aftermarket 1/4 turn throttle and maybe that's not allowing me to have the "optimum" setting for the injector cable.

I already yanked the pump and plugged it with the products from Tyga and all I have left is to find a nice/easy way to get the reservoir out of the frame today.

I do have a new "big and clear" fuel filter so I'll try that for now.


Hey Matt, once I plug the oil injector pump hole with the little alluminum cap, is it next to impossible to remove?

Jae

Jae, the alloy cap that you use to plug oil pump hole is held in place with a 2 bolt bracket that you should have purchased as well (it sits above the cap) I'm sure you can permanently fit the cap with silicone or ? Well, the experts should be by soon.
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FILOLI - Fight, Love, Live

I got both the plug and braket from Matt @ Tyga. But the bracket I have is just a little tab with one hole in it. I was wondering about the hole (without threads) that is still unplugged that leads into the crankcase. Do I just tape it up?

Mine came with 2 holes, it's blue alloy type bracket that fits perfectly over alloy cap/plug and bolts up in the 2 holes in the case. I am sure 1 bolt would (properly torqued) would be sufficient enough.
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FILOLI - Fight, Love, Live

There's basically two types of oil injection. The old type which was used up and into '91 has one hole in the cases for the oil pump drive, and the oil is fed into the intake side of the carbs.

Later model NSRs (most MC21 and all MC28) have an extra oil feel direct to the RH main bearing, and use a different oil pump.

On early models (single hole) you only need to plug this one hole, but on the later models you need to plug the main drice hole and the extra feed hole.

The 2T plug (TYLY-0012) is just held in the main drive hole with some RTV sealant to stop leaks. Plug holder (TYLY-0015) can then be fitted to hold it in. Never had one come loose. The plate with two holes is supplied by another manufacturer.

The extra feed hole can be blocked in a number of ways. HRC supply a little alloy plug that you ram down the feed hole, and is pretty much impossible to remove. I like to use epoxy, and have never had a problem. Even removing the epoxy to return the cases back to oil pump use is not too difficult. I've also seen it done with various silicone sealants etc. The feed hole does need to be blocked as it's a direct link to the crankcase.

Removing the 2T plug can be done by drilling and tapping into the centre of the plug and using a slide hammer or something to break the sealant.

Maybe on the next batch I'll redesign it, and the holder, to keep the standard o ring, so removal is easy. It's just that when I build a race engine it usually stays a race engine, so I like to make sure everything's sealed and tight.

How many people out there actually revert back to oil pump after doing the pre-mix conversion?

Thanks Matt! I'll go ahead and use epoxy for the crankcase feed. I wasn't really planning on going back to injectors after this but thought it'd be nice to know if I could.

...my mc28 is premix.....i only ever ran my rg500 and rd500 like that to get a better mix,a well known tuner once told me the oil pump was to blame for many of the failures
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Ducati 916 SP
Honda NSR250R MC28 SP
Ferrari 348tb
Mercedes E55 kompressor AMG

I've never personally seen an NSR oil pump fail, but it is a mechanical part, and any mechanical item is liable to failure somewhere along the line.

The (well documented) benefit of premix is that you are directly responsible for the consistency of the 2-stoke mixture. The downside is if you hit reserve or run the tank dry whilst flat out in top, NOTHING is pumped into the bottom-end (and consequently the top-end too). The oil pump continually pumps while the motor is spinning and there is oil in the reservoir.

For the road I will choose the oil pump (on an NSR) whenever possible - for convenience if nothing else!
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Andy.
NSR-WORLD.COM

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...andy,yes the biggest flaw is running out of petrol....oh and forgetting the bike is premix when you fuel up...lol
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Ducati 916 SP
Honda NSR250R MC28 SP
Ferrari 348tb
Mercedes E55 kompressor AMG

Im up to my ears in premixing.. 72 gallons at a time for the boat = no fun.
Clear filters and no problems