So the OD 99s would be the way to go? The OS plug seemed to work well, it would idle all day, but the tuning window was very small.

thanks again for tips.

It depends on temps the 99's are hot and the 97's are cold right now i have a 99 in and will be switching to a 97 later this month since the tempertures will go down

I have the same question? I want to know will they current GRP piston/sleeve/rod fit the Ninja Bo1a?

So whats the story with GRP engines? I read a rumor that the GRP factory burned down and that they were discontinuing their line of engines. Is that true:confused:

Its true, suc_ks cause the grp motors were great after I learned how to tune properly. Factory burned about 3 months ago and a month later they announced they would be making only tires. There was a rumor going around that the motors were going to be released under a BOSS name but that has since bean squashed. Loved my grp's (had 5 at one time-but sold them) bought a ninja and its god. So far first race 20 minute A pitted at 10 min temped 225
Parts are kind of hard tocome by now-you could make a small fortune if you could come up with some grp rods

I know it has been asked bfore, I used the search tool but didn't come up with any results. Is there a rod that can be used in the grp engines besides the stock rod?

I too,would like to know the answer to the two statements above.

From what I understand the grp engines and the old ninjas (not the os based jx series) the parts are interchangeable as the the older ninjas were made by grp. The older ninjas are MR ninja with the MR. Meaning Mario Rossi tuned. Just like the new grps
Hope this helps, as far as I know there is not another rod that fits the grp besides the nontuned version rod (they are also hard to find))

Who needs a rod? I have two that im not going to use actually. I bought the untuned and was planning on putting the tuned rod in and decided to just keep the untuned in there.

i have one that is new. The other one has about half a quart on it. i was going to break in my grp .28 but decided to just give up on it.

Thanks beta bob for your help. I'll give the OD plugs a shot this weekend.

F/S GRP .21 Tuned
 

my lhs has a ton of those GRP Ninjas with a weird colored head( white looking) they are pricey, in the mid $400's...There are a lot of great motors out there for under $400

those are the On-road version's if im not mistaken.

Sounds like a magnesium head to me, some of the offroad version came with this. If I remember correctly they were $500+ motors
One of our local guys has an old mr ninja with mag head and it flat out screams way faster than any orange head grp

You are mistaken. All of the Mario Rossi Tuned versions have the "white" magnesium head, both on-road and off-road.

A little birdie told me horizion is going to distribute parts for the grp engines, like rods and pistions and all parts. I'll keep my eyes open.