Kawi2strokes.com Forum

the biggest problem with trying to repair oilpumps is they all have the same problem, the tangs missing off the pulley or the top centre hole is stripped - what gives

hey i aint no fiend more why the top centre hole more than others?

This evening I checked my oil pump banjo bolts and found one barely better than finger tight. When I tried to tighten it, it stripped. After making some measurements and doing some probing, I found about six more threads than the bolt could reach, before starting to block the internal passage. So I welded an extension on the banjo bolt, making it about 6mm longer, drilled the center, cleaned up the threads with a die, and re-assembled. It's plenty tight now, using the six threads farther in than the stripped ones.

Now I'd like to find a source of 6x1mm banjo bolts with a 6mm longer threaded part than the stock ones. It would make it very difficult to strip the others in the future.

I thought about it, and haven't discarded it, but tapping for a Helicoil or a similar thread repair insert requires getting every little chip out, so I probably need to remove the pump, at least. Also buy the kit, etc. When it stripped the other night, I just wanted to get it fixed quickly, without all the ordering, paying, tapping, cleaning, etc. Then when I saw all the good threads left, I thought that using longer bolts in the first place would probably prevent any others from stripping in the future.

OK, here's the whole story. I removed all four stock banjo bolts from my pump, measured each hole depth and thread depth, made new bolts with safety wire holes in the heads, installed rubber seal type washers, and reassembled everything and wired it all in place. The safety wire gives me some confidence to just snug them up, but not worry that they will vibrate loose.

Outlet bolt hole closest to cylinders (R cyl): 8mm deep, fully threaded
Outlet bolt hole toward rear (L, cyl): 14mm deep, 9-10 threads to cross passage (1mm per thread)
Outlet bolt hole toward front (C, cyl): 14mm deep, 9-10 threads to cross passage
Inlet bolt hole: very deep hole, but threaded only about 2 threads more than stock bolt

So for the R outlet, I was able to get about 2 more threads engaged than the stock bolt. I had to use care not to make the bolt too long, as it would hit the pump's valve sleeve if it were.

For the L outlet and the C outlet, I was able to make bolts that engage at least 5 threads more than the stock ones did. The L outlet was the repair that I started this thread with.

For the inlet, I found my threads essentially stripped before I started. The bolt was not very tight, and when I turned it, it would not tighten. I took off the pump cover, which had its little tab broken off, but still in place (!) so I could see inside, and saw plenty of room for threads, but only two unstripped ones. I used a greased tap, and tapped it all the way through and cleaned all the chips out that the grease didn't catch (vacuum, rinse with WD-40, repeat a few times), made a bolt 5 threads longer than stock (full length of my blank bolts) and put it in. Then I TIG welded the tab back on the cover, which was quite a micro-welding job.

So (on my pump) to use a long bolt on the inlet to fix stripped threads required tapping deeper, which means you might as well install a Helicoil. The R outlet doesn't have enough depth to fix stripped threads with a longer bolt, but might be worth using one that's 2mm longer than stock to prevent trouble, although great care has to be used not to make it too long. The L and C outlets can take bolts 5mm longer than stock for a repair or strip prevention.

Since there is probably variation between pumps, and since this isn't a clear cut procedure, I don't want to get into making longer bolts for others. They might end up causing more trouble than they fix. But if anyone wants to do it himself, I'll be glad to send blank bolts, since I still have about 96 of my original 100 in the bag.